| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Berndt, Sonja, I, et al.
(författare)
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Distinct germline genetic susceptibility profiles identified for common non-Hodgkin lymphoma subtypes
- 2022
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Ingår i: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 36:12, s. 2835-2844
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Tidskriftsartikel (refereegranskat)abstract
- Lymphoma risk is elevated for relatives with common non-Hodgkin lymphoma (NHL) subtypes, suggesting shared genetic susceptibility across subtypes. To evaluate the extent of mutual heritability among NHL subtypes and discover novel loci shared among subtypes, we analyzed data from eight genome-wide association studies within the InterLymph Consortium, including 10,629 cases and 9505 controls. We utilized Association analysis based on SubSETs (ASSET) to discover loci for subsets of NHL subtypes and evaluated shared heritability across the genome using Genome-wide Complex Trait Analysis (GCTA) and polygenic risk scores. We discovered 17 genome-wide significant loci (P < 5 × 10−8) for subsets of NHL subtypes, including a novel locus at 10q23.33 (HHEX) (P = 3.27 × 10−9). Most subset associations were driven primarily by only one subtype. Genome-wide genetic correlations between pairs of subtypes varied broadly from 0.20 to 0.86, suggesting substantial heterogeneity in the extent of shared heritability among subtypes. Polygenic risk score analyses of established loci for different lymphoid malignancies identified strong associations with some NHL subtypes (P < 5 × 10−8), but weak or null associations with others. Although our analyses suggest partially shared heritability and biological pathways, they reveal substantial heterogeneity among NHL subtypes with each having its own distinct germline genetic architecture.
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| 4. |
- Berndt, Sonja I., et al.
(författare)
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Genome-wide association study identifies multiple risk loci for chronic lymphocytic leukemia
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:8, s. 868-U202
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P = 1.22 x 10(-14)), 18q21.33 (BCL2, P = 7.76 x 10(-11)), 11p15.5 (C11orf21, P = 2.15 x 10(-10)), 4q25 (LEF1, P = 4.24 x 10(-10)), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P = 2.50 x 10(-9)), 9p21.3 (CDKN2B-AS1, P = 1.27 x 10(-8)), 18q21.32 (PMAIP1, P = 2.51 x 10(-8)), 15q15.1 (BMF, P = 2.71 x 10(-10)) and 2p22.2 (QPCT, P = 1.68 x 10(-8)), as well as an independent signal at an established locus (2q13, ACOXL, P = 2.08 x 10(-18)). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P = 5.40 x 10(-8)) and 5p15.33 (TERT, P = 1.92 x 10(-7)). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.
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| 5. |
- Berndt, Sonja I., et al.
(författare)
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Meta-analysis of genome-wide association studies discovers multiple loci for chronic lymphocytic leukemia
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Chronic lymphocytic leukemia (CLL) is a common lymphoid malignancy with strong heritability. To further understand the genetic susceptibility for CLL and identify common loci associated with risk, we conducted a meta-analysis of four genome-wide association studies (GWAS) composed of 3,100 cases and 7,667 controls with follow-up replication in 1,958 cases and 5,530 controls. Here we report three new loci at 3p24.1 (rs9880772, EOMES, P = 2.55 x 10(-11)), 6p25.2 (rs73718779, SERPINB6, P = 1.97 x 10(-8)) and 3q28 (rs9815073, LPP, P = 3.62 x 10(-8)), as well as a new independent SNP at the known 2q13 locus (rs9308731, BCL2L11, P = 1.00 x 10(-11)) in the combined analysis. We find suggestive evidence (P<5 x 10(-7)) for two additional new loci at 4q24 (rs10028805, BANK1, P = 7.19 x 10(-8)) and 3p22.2 (rs1274963, CSRNP1, P = 2.12 x 10(-7)). Pathway analyses of new and known CLL loci consistently show a strong role for apoptosis, providing further evidence for the importance of this biological pathway in CLL susceptibility.
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| 6. |
- Dima, Danai, et al.
(författare)
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Subcortical volumes across the lifespan : Data from 18,605 healthy individuals aged 3-90 years.
- 2022
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Ingår i: Human Brain Mapping. - : Wiley. - 1065-9471 .- 1097-0193. ; 43:1, s. 452-469
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Tidskriftsartikel (refereegranskat)abstract
- Age has a major effect on brain volume. However, the normative studies available are constrained by small sample sizes, restricted age coverage and significant methodological variability. These limitations introduce inconsistencies and may obscure or distort the lifespan trajectories of brain morphometry. In response, we capitalized on the resources of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium to examine age-related trajectories inferred from cross-sectional measures of the ventricles, the basal ganglia (caudate, putamen, pallidum, and nucleus accumbens), the thalamus, hippocampus and amygdala using magnetic resonance imaging data obtained from 18,605 individuals aged 3-90 years. All subcortical structure volumes were at their maximum value early in life. The volume of the basal ganglia showed a monotonic negative association with age thereafter; there was no significant association between age and the volumes of the thalamus, amygdala and the hippocampus (with some degree of decline in thalamus) until the sixth decade of life after which they also showed a steep negative association with age. The lateral ventricles showed continuous enlargement throughout the lifespan. Age was positively associated with inter-individual variability in the hippocampus and amygdala and the lateral ventricles. These results were robust to potential confounders and could be used to examine the functional significance of deviations from typical age-related morphometric patterns.
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| 7. |
- Frangou, Sophia, et al.
(författare)
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Cortical thickness across the lifespan : Data from 17,075 healthy individuals aged 3-90 years
- 2022
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Ingår i: Human Brain Mapping. - : John Wiley & Sons. - 1065-9471 .- 1097-0193. ; 43:1, s. 431-451
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Tidskriftsartikel (refereegranskat)abstract
- Delineating the association of age and cortical thickness in healthy individuals is critical given the association of cortical thickness with cognition and behavior. Previous research has shown that robust estimates of the association between age and brain morphometry require large-scale studies. In response, we used cross-sectional data from 17,075 individuals aged 3-90 years from the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium to infer age-related changes in cortical thickness. We used fractional polynomial (FP) regression to quantify the association between age and cortical thickness, and we computed normalized growth centiles using the parametric Lambda, Mu, and Sigma method. Interindividual variability was estimated using meta-analysis and one-way analysis of variance. For most regions, their highest cortical thickness value was observed in childhood. Age and cortical thickness showed a negative association; the slope was steeper up to the third decade of life and more gradual thereafter; notable exceptions to this general pattern were entorhinal, temporopolar, and anterior cingulate cortices. Interindividual variability was largest in temporal and frontal regions across the lifespan. Age and its FP combinations explained up to 59% variance in cortical thickness. These results may form the basis of further investigation on normative deviation in cortical thickness and its significance for behavioral and cognitive outcomes.
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| 8. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 9. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 10. |
- Cerhan, James R., et al.
(författare)
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Genome-wide association study identifies multiple susceptibility loci for diffuse large B cell lymphoma
- 2014
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 46:11, s. 1233-1238
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Tidskriftsartikel (refereegranskat)abstract
- Diffuse large B cell lymphoma (DLBCL) is the most common lymphoma subtype and is clinically aggressive. To identify genetic susceptibility loci for DLBCL, we conducted a meta-analysis of 3 new genome-wide association studies (GWAS) and 1 previous scan, totaling 3,857 cases and 7,666 controls of European ancestry, with additional genotyping of 9 promising SNPs in 1,359 cases and 4,557 controls. In our multi-stage analysis, five independent SNPs in four loci achieved genome-wide significance marked by rs116446171 at 6p25.3 (EXOC2; P = 2.33 x 10(-21)), rs2523607 at 6p21.33 (HLA-B; P = 2.40 x 10(-10)), rs79480871 at 2p23.3 (NCOA1; P = 4.23 x 10(-8)) and two independent SNPs, rs13255292 and rs4733601, at 8q24.21 (PVT1; P = 9.98 x 10(-13) and 3.63 x 10(-11), respectively). These data provide substantial new evidence for genetic susceptibility to this B cell malignancy and point to pathways involved in immune recognition and immune function in the pathogenesis of DLBCL.
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| 11. |
- Loo, Jacky F. C., et al.
(författare)
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Integrated Printed Microfluidic Biosensors
- 2019
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Ingår i: Trends in Biotechnology. - : ELSEVIER SCIENCE LONDON. - 0167-7799 .- 1879-3096. ; 37:10, s. 1104-1120
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Forskningsöversikt (refereegranskat)abstract
- Integrated printed microfluidic biosensors are one of the most recent point-of-care (POC) sensor developments. Fast turnaround time for production and ease of customization, enabled by the integration of recognition elements and transducers, are key for on-site biosensing for both healthcare and industry and for speeding up translation to real-life applications. Here, we provide an overview of recent progress in printed microfluidics, from the 2D to the 4D level, accompanied by novel sensing element integration. We also explore the latest trends in integrated printed microfluidics for healthcare, especially POC diagnostics, and food safety applications.
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| 12. |
- Machiela, Mitchell J., et al.
(författare)
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Genetically predicted longer telomere length is associated with increased risk of B-cell lymphoma subtypes
- 2016
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 25:8, s. 1663-1676
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Tidskriftsartikel (refereegranskat)abstract
- Evidence from a small number of studies suggests that longer telomere length measured in peripheral leukocytes is associated with an increased risk of non-Hodgkin lymphoma (NHL). However, these studies may be biased by reverse causation, confounded by unmeasured environmental exposures and might miss time points for which prospective telomere measurement would best reveal a relationship between telomere length and NHL risk. We performed an analysis of genetically inferred telomere length and NHL risk in a study of 10 102 NHL cases of the four most common B-cell histologic types and 9562 controls using a genetic risk score (GRS) comprising nine telomere length-associated single-nucleotide polymorphisms. This approach uses existing genotype data and estimates telomere length by weighing the number of telomere length-associated variant alleles an individual carries with the published change in kb of telomere length. The analysis of the telomere length GRS resulted in an association between longer telomere length and increased NHL risk [four B-cell histologic types combined; odds ratio (OR) = 1.49, 95% CI 1.22-1.82, P-value = 8.5 x 10(-5)]. Subtype-specific analyses indicated that chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) was the principal NHL subtype contributing to this association (OR = 2.60, 95% CI 1.93-3.51, P-value = 4.0 x 10(-10)). Significant interactions were observed across strata of sex for CLL/SLL and marginal zone lymphoma subtypes as well as age for the follicular lymphoma subtype. Our results indicate that a genetic background that favors longer telomere length may increase NHL risk, particularly risk of CLL/SLL, and are consistent with earlier studies relating longer telomere length with increased NHL risk.
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| 13. |
- Skibola, Christine F, et al.
(författare)
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Genome-wide Association Study Identifies Five Susceptibility Loci for Follicular Lymphoma outside the HLA Region.
- 2014
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 95:4, s. 462-471
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWASs) of follicular lymphoma (FL) have previously identified human leukocyte antigen (HLA) gene variants. To identify additional FL susceptibility loci, we conducted a large-scale two-stage GWAS in 4,523 case subjects and 13,344 control subjects of European ancestry. Five non-HLA loci were associated with FL risk: 11q23.3 (rs4938573, p = 5.79 × 10(-20)) near CXCR5; 11q24.3 (rs4937362, p = 6.76 × 10(-11)) near ETS1; 3q28 (rs6444305, p = 1.10 × 10(-10)) in LPP; 18q21.33 (rs17749561, p = 8.28 × 10(-10)) near BCL2; and 8q24.21 (rs13254990, p = 1.06 × 10(-8)) near PVT1. In an analysis of the HLA region, we identified four linked HLA-DRβ1 multiallelic amino acids at positions 11, 13, 28, and 30 that were associated with FL risk (pomnibus = 4.20 × 10(-67) to 2.67 × 10(-70)). Additional independent signals included rs17203612 in HLA class II (odds ratio [ORper-allele] = 1.44; p = 4.59 × 10(-16)) and rs3130437 in HLA class I (ORper-allele = 1.23; p = 8.23 × 10(-9)). Our findings further expand the number of loci associated with FL and provide evidence that multiple common variants outside the HLA region make a significant contribution to FL risk.
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| 14. |
- Vijai, Joseph, et al.
(författare)
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A genome-wide association study of marginal zone lymphoma shows association to the HLA region
- 2015
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Marginal zone lymphoma (MZL) is the third most common subtype of B-cell non-Hodgkin lymphoma. Here we perform a two-stage GWAS of 1,281 MZL cases and 7,127 controls of European ancestry and identify two independent loci near BTNL2 (rs9461741, P - 3.95 x 10(-15)) and HLA-B (rs2922994, P - 2.43 x 10(-9)) in the HLA region significantly associated with MZL risk. This is the first evidence that genetic variation in the major histocompatibility complex influences MZL susceptibility.
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| 15. |
- Axfors, Cathrine, et al.
(författare)
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Mortality outcomes with hydroxychloroquine and chloroquine in COVID-19 from an international collaborative meta-analysis of randomized trials
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Substantial COVID-19 research investment has been allocated to randomized clinical trials (RCTs) on hydroxychloroquine/chloroquine, which currently face recruitment challenges or early discontinuation. We aim to estimate the effects of hydroxychloroquine and chloroquine on survival in COVID-19 from all currently available RCT evidence, published and unpublished. We present a rapid meta-analysis of ongoing, completed, or discontinued RCTs on hydroxychloroquine or chloroquine treatment for any COVID-19 patients (protocol: https://osf.io/QESV4/). We systematically identified unpublished RCTs (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, Cochrane COVID-registry up to June 11, 2020), and published RCTs (PubMed, medRxiv and bioRxiv up to October 16, 2020). All-cause mortality has been extracted (publications/preprints) or requested from investigators and combined in random-effects meta-analyses, calculating odds ratios (ORs) with 95% confidence intervals (CIs), separately for hydroxychloroquine and chloroquine. Prespecified subgroup analyses include patient setting, diagnostic confirmation, control type, and publication status. Sixty-three trials were potentially eligible. We included 14 unpublished trials (1308 patients) and 14 publications/preprints (9011 patients). Results for hydroxychloroquine are dominated by RECOVERY and WHO SOLIDARITY, two highly pragmatic trials, which employed relatively high doses and included 4716 and 1853 patients, respectively (67% of the total sample size). The combined OR on all-cause mortality for hydroxychloroquine is 1.11 (95% CI: 1.02, 1.20; I-2=0%; 26 trials; 10,012 patients) and for chloroquine 1.77 (95%CI: 0.15, 21.13, I-2=0%; 4 trials; 307 patients). We identified no subgroup effects. We found that treatment with hydroxychloroquine is associated with increased mortality in COVID-19 patients, and there is no benefit of chloroquine. Findings have unclear generalizability to outpatients, children, pregnant women, and people with comorbidities. Hydroxychloroquine and chloroquine have been investigated as a potential treatment for Covid-19 in several clinical trials. Here the authors report a meta-analysis of published and unpublished trials, and show that treatment with hydroxychloroquine for patients with Covid-19 was associated with increased mortality, and there was no benefit from chloroquine.
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| 16. |
- Bernatsky, Sasha, et al.
(författare)
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Lupus-related single nucleotide polymorphisms and risk of diffuse large B-cell lymphoma
- 2017
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Ingår i: Lupus Science and Medicine. - : BMJ. - 2053-8790. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Determinants of the increased risk of diffuse large B-cell lymphoma (DLBCL) in SLE are unclear. Using data from a recent lymphoma genome-wide association study (GWAS), we assessed whether certain lupus-related single nucleotide polymorphisms (SNPs) were also associated with DLBCL. Methods: GWAS data on European Caucasians from the International Lymphoma Epidemiology Consortium (InterLymph) provided a total of 3857 DLBCL cases and 7666 general-population controls. Data were pooled in a random-effects meta-analysis. Results: Among the 28 SLE-related SNPs investigated, the two most convincingly associated with risk of DLBCL included the CD40 SLE risk allele rs4810485 on chromosome 20q13 (OR per risk allele=1.09, 95% CI 1.02 to 1.16, p=0.0134), and the HLA SLE risk allele rs1270942 on chromosome 6p21.33 (OR per risk allele=1.17, 95% CI 1.01 to 1.36, p=0.0362). Of additional possible interest were rs2205960 and rs12537284. The rs2205960 SNP, related to a cytokine of the tumour necrosis factor superfamily TNFSF4, was associated with an OR per risk allele of 1.07, 95% CI 1.00 to 1.16, p=0.0549. The OR for the rs12537284 (chromosome 7q32, IRF5 gene) risk allele was 1.08, 95% CI 0.99 to 1.18, p=0.0765. Conclusions: These data suggest several plausible genetic links between DLBCL and SLE.
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| 17. |
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| 18. |
- Newman, Jeffrey D., et al.
(författare)
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Catalytic materials, membranes and fabrication technologies suitable for the construction of amperometric biosensors
- 1995
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 67:24, s. 4594-4599
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A selection of recently available catalytic carbon powders were assessed and compared with the more conventionally used platinized material. Their suitability for incorporation in amperometric biosensors is discussed, In conjunction with this study, methods of applying membranes to the surfaces of these devices were investigated. Advanced fabrication technologies, potentially suitable for scale-up of sensor production, such as screen printing and ink-jet printing, were used for manufacture of the complete sensor structure. Hydrogen peroxide-sensing electrodes and glucose biosensors were produced as model systems, demonstrating the advantages of these approaches. The commercially available rhodinized carbon MCA4 produced a high current density at low potentials over a plateau region (300-400 mV vs SCE). In addition, direct oxidation of glucose (seen with platinized carbon) was not observed at the chosen potential of +350 mV. Further interference studies using fermentation media highlighted its suitability as an electrode material for use in complex samples. Ink-jet printing proved to be a successful method for the deposition of Nafion membranes of defined and reproducible geometry.
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| 19. |
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| 20. |
- Psoma, Sotiria D., et al.
(författare)
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A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors
- 2010
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 26:4, s. 1582-1587
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Tidskriftsartikel (refereegranskat)abstract
- The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzymes activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the films surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.
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| 21. |
- Alcock, S. J., et al.
(författare)
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Advances in the use of in vivo sensors
- 1992
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 7:4, s. 243-254
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The sixth workshop of the European Community Concerted Action on Chemical sensors for in vivo monitoring was held at Snogeholm, Sweden, in October 1991. The meeting reviewed recent in vivo and ex vivo results, and also included a shorter session on ethical and safety problems.
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| 22. |
- Azharuddin, Mohammad, 1986-, et al.
(författare)
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A repertoire of biomedical applications of noble metal nanoparticles
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:49, s. 6964-6996
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Forskningsöversikt (refereegranskat)abstract
- Noble metals comprise any of several metallic chemical elements that are outstandingly resistant to corrosion and oxidation, even at elevated temperatures. This group is not strictly defined, but the tentative list includes ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold, in order of atomic number. The emerging properties of noble metal nanoparticles are attracting huge interest from the translational scientific community and have led to an unprecedented expansion of research and exploration of applications in biotechnology and biomedicine. Noble metal nanomaterials can be synthesised both by top-down and bottom up approaches, as well as via organism-assisted routes, and subsequently modified appropriately for the field of use. Nanoscale analogues of gold, silver, platinum, and palladium in particular, have gained primary importance owing to their excellent intrinsic properties and diversity of applications; they offer unique functional attributes, which are quite unlike the bulk material. Modulation of noble metal nanoparticles in terms of size, shape and surface functionalisation has endowed them with unusual capabilities and manipulation at the chemical level, which can lead to changes in their electrical, chemical, optical, spectral and other intrinsic properties. Such flexibility in multi-functionalisation delivers Ockhams razor to applied biomedical science. In this feature article, we highlight recent advances in the adaptation of noble metal nanomaterials and their biomedical applications in therapeutics, diagnostics and sensing.
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| 23. |
- Berti, Francesca, et al.
(författare)
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One-Dimensional Polyaniline Nanotubes for Enhanced Chemical and Biochemical Sensing
- 2011
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Ingår i: Sensors and Microsystems. - Dordrecht : Springer Netherlands. - 9789400713239 ; , s. 311-315
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this work we explored a simple, cheap and fast route to grow polyaniline (PANI) nanotubes arranged in an ordered structure directly on an electrode surface by electrochemical polymerisation. The deposited nanostructures were electrochemically and morphologically characterised and then used as a functional substrate for biochemical sensing by combining the intrinsic advantages of nanostructures as optimal transducers and the well known benefits of molecularly imprinted polymers (MIPs) as receptors. The hybrid nanostructured-MIP sensor was applied to the molecular recognition of catechol. Moreover, a gas sensing application was also investigated by exploiting resistance variation of the polymer in presence of different gases (CO, NO2, NH3 and ethanol).
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| 24. |
- Berti, Francesca, et al.
(författare)
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Quasi-monodimensional polyaniline nanostructures for enhanced molecularly imprinted polymer-based sensing
- 2010
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 26:2, s. 497-503
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in nanotechnology have allowed significant progress in utilising cutting-edge techniques associated with nanomaterials and nano-fabrication to expand the scope and capability of biosensors to a new level of novelty and functionality. The aim of this work was the development and characterisation of conductive polyaniline (PANI) nanostructures for applications in electrochemical biosensing. We explore a simple, inexpensive and fast route to grow PANI nanotubes, arranged in an ordered structure directly on an electrode surface, by electrochemical polymerisation using alumina nanoporous membranes as a nano-mould. The deposited nanostructures have been characterised electrochemically and morphologically prior to grafting with a molecularly imprinted polymer (MIP) receptor in order to create a model sensor for catechol detection. In this way, PANI nanostructures resulted in a conductive nanowire system which allowed direct electrical connection between the electrode and the synthetic receptor (MIP). To our knowledge, this is the first example of integration between molecularly imprinted polymers and PANI nanostructured electrodes. The advantages of using nanostructures in this particular biosensing application have been evaluated by comparing the analytical performance of the sensor with an analogous non-nanostructured MIP-sensor for catechol detection that was previously developed. A significantly lower limit of detection for catechol has been obtained (29 nM, one order of magnitude), thus demonstrating that the nanostructures are capable of improving the analytical performance of the sensor. (C) 2010 Elsevier B.V. All rights reserved.
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| 25. |
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Biomedical materials and diagnostic devices
- 2012
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- "The functional materials with the most promising outlook have the ability to precisely adjust the biological phenomenon in a controlled mode. Engineering of advanced bio- materials has found striking applications in used for biomedical and diagnostic device applications, such as cell separation, stem-cell, drug delivery, hyperthermia, automated DNA extraction, gene targeting, resonance imaging, biosensors, tissue engineering and organ regeneration"--Provided by publisher.
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| 26. |
- Bonini, Francesca, et al.
(författare)
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Surface imprinted beads for the recognition of human serum albumin
- 2007
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 22:10-sep, s. 2322-2328
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of poly-aminophenylboronic acid (ABPA) imprinted beads for the recognition of the protein human serum albumin (HSA) is reported. In order to create homogeneous recognition sites, covalent immobilisation of the template HSA was exploited. The resulting imprinted beads were selective for HSA. The indirect imprinting factor (IF) calculated from supernatant was 1.6 and the direct IF, evaluated from the protein recovered from the beads, was 1.9. The binding capacity was 1.4 mg/g, which is comparable to commercially available affinity materials. The specificity of the HSA recognition was evaluated with competitive experiments, indicating a molar ratio 4.5/1 of competitor was necessary to displace half of the bound HSA. The recognition and binding of the imprinted beads was also tested with a complex sample, human serum and targeted removal of HSA without a loss of the other protein components was demonstrated. The easy preparation protocol of derivatised beads and a good protein recognition properties make the approach an attractive solution to analytical and bio-analytical problems in the field of biotechnology. (c) 2007 Elsevier B.V. All rights reserved.
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| 27. |
- Bossi, Alessandra, et al.
(författare)
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Patterned gallium surfaces as molecular mirrors
- 2007
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 23:2, s. 290-294
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Tidskriftsartikel (refereegranskat)abstract
- An entirely new means of printing molecular information on a planar film, involving casting nanoscale impressions of the template protein molecules in molten gallium, is presented here for the first time. The metallic imprints not only replicate the shape and size of the proteins used as template. They also show specific binding for the template species. Such a simple approach to the creation of antibody-like properties in metallic mirrors can lead to applications in separations, microfluidic devices, and the development of new optical and electronic sensors, and will be of interest to chemists, materials scientists, analytical specialists, and electronic engineers.
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| 28. |
- Bossi, Alessandra, et al.
(författare)
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Properties of poly-aminophenylboronate coatings in capillary electrophoresis for the selective separation of diastereoisomers and glycoproteins
- 2004
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1023:2, s. 297-303
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Tidskriftsartikel (refereegranskat)abstract
- The polymerisation of 3-aminophenylboronic acid (APBA) in aqueous environment has been used for the open tubular modification of capillary electrophoresis (CE) capillaries. Being poly-APBA endowed with boronic acid, aromatic rings and secondary amines groups, it posses a variety of functional groups affecting selectivity. Diastereoisomers (e.g. ascorbic and isoascorbic acid) and proteins (e.g. haemoglobins) were successfully separated onto poly-APBA column, by means of a combination of electrophoresis and open tubular electrochromatography. The mechanism of selection was investigated: results indicate an interplay between enhancing or silencing the contribution of the protonable functionahties (amino groups, boronic acid). The properties of APBA polymer coating make it attractive for CE separation and for further application in affinity separations and chip technologies.
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| 29. |
- Brito, Paula, et al.
(författare)
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Mediated Biocatalytic Electrodes and Enzyme Stabilisation for Power Generation
- 2010
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Ingår i: Electroanalysis. - : John Wiley andamp;amp; Sons, Ltd. - 1040-0397 .- 1521-4109. ; 22:08-jul, s. 732-743
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Forskningsöversikt (refereegranskat)abstract
- This contribution considers the origins, principles and recent literature published on enzymatic biofuel cells, with a focus on performance and stability. Modified or new biofuel cell components, such as modified electrodes, new enzymes and the use of new mediators to improve power output and stability are reviewed. The development of biofuel cells to date leaves huge potential for further improvement and practical application. Cooperation between different fields of science is essential to realise important potential applications in human health and power generation; future research needs to achieve this are discussed.
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| 30. |
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| 31. |
- Dennison, M. J., et al.
(författare)
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Biosensors for environmental monitoring
- 1995
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Ingår i: Biotechnology Advances. - : Elsevier. - 0734-9750 .- 1873-1899. ; 13:1, s. 1-12
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Forskningsöversikt (refereegranskat)abstract
- Increasing environmental legislation which controls the release and the levels of certain chemicals in the environment has created a need for reliable monitoring of these substances in air, soil and especially water. Conventional analytical techniques, although highly precise, suffer from the disadvantages of high cost, the need for trained personnel and the fact that they are mostly laboratory bound. Biosensors because of their specificity, fast response times, low cost, portability, ease of use and a continuous real time signal, can present distinct advantages in certain cases. Their biological base makes them ideal for toxicological measurements which are suited for health and safety applications. Over the last 3–4 years there has been an increase in the number of publications concerning biosensors for environmental monitoring, especially in the field of pesticide measurements.
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| 32. |
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| 33. |
- Ge, Yi, et al.
(författare)
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Molecularly Imprinted Sorbent Assays : Recent Developments and Applications
- 2009
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Ingår i: Chemistry - A European Journal. - : John Wiley & Sons. - 0947-6539 .- 1521-3765. ; 15:33, s. 8100-8107
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Forskningsöversikt (refereegranskat)abstract
- Molecular imprinting has attracted considerable attention, because it offers the tantalising prospect of specific antibody-mimicking recognition and binding sites, coupled with several distinct advantages such as excellent stability, ease of preparation and low cost. In this Minireview, recent progress in molecularly imprinted sorbent assays is discussed, with a particular emphasis on the most significant developments and applications over the last few years.
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| 34. |
- Ge, Yi, et al.
(författare)
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Too large to fit? Recent developments in macromolecular imprinting
- 2008
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Ingår i: Trends in Biotechnology. - : Elsevier Science B.V., Amsterdam.. - 0167-7799 .- 1879-3096. ; 26:4, s. 218-224
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Forskningsöversikt (refereegranskat)abstract
- Molecular imprinting involves the synthesis of polymers in the presence of a template to produce complementary binding sites with specific recognition ability. The technique has been successfully applied as a measurement and separation technology, producing a uniquely robust and antibody-like polymeric material. Low molecular weight molecules have been extensively exploited as imprint templates, leading to significant achievements in solid-phase extraction, sensing and enzyme-like catalysis. By contrast, macromolecular imprinting remains underdeveloped, principally because of the lack of binding site accessibility. In this review, we focus on the most recent developments in this area, not only covering the widespread use of biological macro-templates but also highlighting the emerging use of synthetic macro-templates, such as dendrimers and hyperbranched polymers.
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| 35. |
- Imani, Roghayeh, et al.
(författare)
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Band edge engineering of TiO2@DNA nanohybrids and implications for capacitive energy storage devices
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 7:23, s. 10438-10448
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Tidskriftsartikel (refereegranskat)abstract
- Novel mesoporous TiO2@DNA nanohybrid electrodes, combining covalently encoded DNA with mesoporous TiO2 microbeads using dopamine as a linker, were prepared and characterised for application in supercapacitors. Detailed information about donor density, charge transfer resistance and chemical capacitance, which have an important role in the performance of an electrochemical device, were studied by electrochemical methods. The results indicated the improvement of electrochemical performance of the TiO2 nanohybrid electrode by DNA surface functionalisation. A supercapacitor was constructed from TiO2@DNA nanohybrids with PBS as the electrolyte. From the supercapacitor experiment, it was found that the addition of DNA played an important role in improving the specific capacitance (C-s) of the TiO2 supercapacitor. The highest Cs value of 8 F g(-1) was observed for TiO2@DNA nanohybrids. The nanohybrid electrodes were shown to be stable over long-term cycling, retaining 95% of their initial specific capacitance after 1500 cycles.
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| 36. |
- Imani, Roghayeh, et al.
(författare)
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Electrochemical detection of DNA damage through visible-light-induced ROS using mesoporous TiO2 microbeads
- 2014
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Ingår i: Electrochemistry communications. - Philadelphia, PA, United States : Elsevier. - 1388-2481 .- 1873-1902. ; 40, s. 84-87
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Tidskriftsartikel (refereegranskat)abstract
- Rapid detection of DNA damage could serve as a basis for genotoxicity studies of new bio-nanoconjugations. A novel TiO2 bio-nanoconjugation, consisting of mesoporous TiO2 microbeads, dopamine (DA) and ss-DNA, was constructed on fluorine-doped tin oxide-coated glass (FTO) and used for the detection of DNA damage in the photocatalytic reaction of TiO2 under visible light. Stable mesoporous TiO2 microbeads films were coated on FTO by the doctor-blade method; dopamine with oxygen containing ligands, was tightly coupled to the titanium surface prepaired under phase coordination. Specific single-strands of DNA were electronically linked to TiO2 by using a dopamine bridge. DNA damage, caused by reactive oxygen species (ROS) that were photogenerated through the photocatalytic reaction, was detected with square wave voltammetry (SWV) by recording the catalytic oxidation current of [Ru(NH3)6]3 +, an intercalated electroactive probe. The ability of antioxidant to protect DNA against damage in the photocatalytic reaction was also tested.
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| 37. |
-
Intelligent Nanomaterials : processes, properties, and applications
- 2012
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- The last three decades have seen extraordinary advances in the generation of new materials based on both fundamental elements and composites, driven by advances in synthetic chemistry and often drawing inspiration from nature. The concept of an intelligent material envisions additional functionality built into the molecular structure, such that a desirable response occurs under defined conditions.Divided into 4 parts: Inorganic Materials; Organic Materials; Composite Materials; and Biomaterials, the 22 chapters cover the latest research and developments in the processing, properties, and applications of intelligent nanomaterials. Included are molecular device materials, biomimetic materials, hybrid-type functionalized polymers-composite materials, information-and energy-transfer materials, as well as environmentally friendly materials.
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| 38. |
- Janko, Matthew, et al.
(författare)
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Contemporary Outcomes After Partial Resection of Infected Aortic Grafts
- 2021
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Ingår i: Annals of Vascular Surgery. - : Elsevier. - 0890-5096 .- 1615-5947. ; 76, s. 202-210
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection.METHODS: A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002 to 2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed.RESULTS: One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%. The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (P = 0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; P = 0.01) as well as aortoenteric fistula (HR 1.9, P = 0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, P = 0.04), as well as those with American Society of Anesthesiologists classification less than 3 (HR 0.35, P = 0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs. 60 years, P = 0.01) and less likely to have patent repairs during follow up (59% vs. 32%, P = 0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs. 29%, P < 0.01)CONCLUSION: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.
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| 39. |
- Janko, Matthew R., et al.
(författare)
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In situ bypass and extra-anatomic bypass procedures result in similar survival in patients with secondary aortoenteric fistulas
- 2021
-
Ingår i: Journal of Vascular Surgery. - : Elsevier. - 0741-5214 .- 1097-6809. ; 73:1, s. 210-221.e1
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The optimal revascularization modality in secondary aortoenteric fistula (SAEF) remains unclear in the literature. The purpose of this investigation was to determine the revascularization approach associated with the lowest morbidity and mortality using real-world data in patients with SAEF. Methods: A retrospective, multi-institutional study of SAEF from 2002 to 2014 was performed using a standardized database. Baseline demographics, comorbidities, and operative and postoperative variables were recorded. The primary outcome was long-term mortality. Descriptive statistics, Kaplan-Meier survival analysis, and univariate and multivariate analyses were performed. Results: During the study period, 182 patients at 34 institutions from 11 countries presented with SAEF (median age, 72 years; 79% male). The initial aortic procedures that resulted in SAEF were 138 surgical grafts (76%) and 42 endografts (23%), with 2 unknown; 102 of the SAEFs (56%) underwent complete excision of infected aortic graft material, followed by in situ (in-line) bypass (ISB), including antibiotic-soaked prosthetic graft (53), autogenous femoral vein (neoaortoiliac surgery; 17), cryopreserved allograft (28), and untreated prosthetic grafts (4). There were 80 patients (44%) who underwent extra-anatomic bypass (EAB) with infected graft excision. Overall median Kaplan-Meier estimated survival was 319 days (interquartile range, 20-2410 days). Stratified by EAB vs ISB, there was no significant difference in Kaplan-Meier estimated survival (P = .82). In comparing EAB vs ISB, EAB patients were older (74 vs 70 years; P = .01), had less operative hemorrhage (1200 mL vs 2000 mL; P = .04), were more likely to initiate dialysis within 30 days postoperatively (15% vs 5%; P = .02), and were less likely to experience aorta-related hemorrhage within 30 days postoperatively (3% aortic stump dehiscence vs 11% anastomotic rupture; P = .03). There were otherwise no significant differences in presentation, comorbidities, and intraoperative or postoperative variables. Multivariable Cox regression showed that the duration of antibiotic use (hazard ratio, 0.92; 95% confidence interval, 0.86-0.98; P = .01) and rifampin use at time of discharge (hazard ratio, 0.20; 95% confidence interval, 0.05-0.86; P = .03) independently decreased mortality. Conclusions: These data suggest that ISB does not offer a survival advantage compared with EAB and does not decrease the risk of postoperative aorta-related hemorrhage. After repair, <50% of SAEF patients survive 10-months. Each week of antibiotic use decreases mortality by 8%. Further study with risk modeling is imperative for this population. (J Vasc Surg 2021;73:210-21.)
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| 40. |
- Karimian, Najmeh, et al.
(författare)
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Electrochemical evaluation of troponin T imprinted polymer receptor
- 2014
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Ingår i: Biosensors & bioelectronics. - USA : Elsevier. - 0956-5663 .- 1873-4235. ; 59, s. 160-165
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Tidskriftsartikel (refereegranskat)abstract
- The selective detection and quantification of macromolecular targets is a fundamental biological mechanism in nature. Molecularly imprinted polymers (MIPs) have been identified as one of the most promising synthetic alternatives to bioreceptors. However, expanding this methodology towards selective recognition of bulky templates such as proteins appears to be extremely challenging due to problems associated with removal of the template from the polymeric network. In this study, polymer imprinted with troponin T (TnT) was assessed using electrochemical methods and the influence of various extraction methods, including conventional immersion extraction, thermal annealing and ultrasonic-assisted extraction, on the binding characteristics of the troponin-to-imprinted polymer receptor was elucidated. Cyclic voltammetric deposition of o-phenylenediamine (o-PD) film in the presence of TnT as a template was performed in acetate buffer (0.5 M, pH 5.2) on a gold substrate. Solvent extraction of the target molecule was optimised and followed by subsequent washing with water. The electrochemistry of a ferro/ferricyanide probe was used to characterise the TnT MIP receptor film. The incubation of the TnT MIP receptor-modified electrode with respect to TnT concentration resulted in a suppression of the ferro/ferricyanide redox current. The dissociation constant (KD) was calculated using a two-site model of template affinity for the TnT MIP receptor. The synthetic TnT MIP receptor had high affinity for TnT with a KD of 2.3×10−13 M.
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| 41. |
- Kashefi-Kheyrabadi, Leila, et al.
(författare)
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Ultrasensitive detection of human liver hepatocellular carcinoma (HepG2) cells using a label-free aptasensor
- 2014
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 86:10, s. 4956-4960
-
Tidskriftsartikel (refereegranskat)abstract
- Liver cancer is one of the most common cancers in the world and has no effective cure, especially in later stages. The development of a tangible protocol for early diagnosis of this disease remains a major challenge. In the present manuscript, an aptamer-based, label-free electrochemical biosensor for the sensitive detection of HepG2, a hepatocellular carcinoma cell line, is described. The target cells are captured in a sandwich architecture using TLS11a aptamer covalently attached to a gold surface and a secondary TLS11a aptamer. The application of TLS11a aptamer as a recognition layer resulted in a sensor with high affinity for HepG2 cancer cells in comparison with control cancer cells of human prostate, breast and colon tumours. The aptasensor delivered a wide linear dynamic range over 1 × 102 – 1 × 106 cell/mL, with a detection limit of 2 cell/mL. This protocol provides a precise method for sensitive detection of liver cancer with significant advantages in terms of simplicity, low cost, and stability.
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| 42. |
- Kyprianou, Dimitris, et al.
(författare)
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New reactive polymer for protein immobilisation on sensor surfaces
- 2009
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Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 24:5, s. 1365-1371
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Tidskriftsartikel (refereegranskat)abstract
- Immobilisation of biorecognition elements on transducer surfaces is a key step in the development of biosensors. The immobilisation needs to be fast, cheap and most importantly should not affect the biorecognition activity of the immobilised receptor. A novel protocol for the covalent immobilisation of biomolecules containing primary amines using an inexpensive and simple polymer is presented. This tridimensional (3D) network leads to a random immobilisation of antibodies on the polymer and ensures the availability of a high percentage of antibody binding sites. The reactivity of the polymer is based on the reaction between primary amines and thioacetal groups included in the polymer network. These functional groups (thioacetal) do not need any further activation in order to react with proteins, making it attractive for sensor fabrication. The novel polymer also contains thiol derivative groups (disulphide groups or thioethers) that promote self-assembling on a metal transducer surface. For demonstration purposes the polymer was immobilised on Au Biacore chips. The resulting polymer layer was characterised using contact angle meter, atomic force microscopy (AFM) and ellipsometry. A general protocol suitable for the immobilisation of bovine serum albumin (BSA), enzymes and antibodies such as polyclonal anti-microcystin-LR antibody and monoclonal anti-prostate specific antigen (anti-PSA) antibody was then optimised. The affinity characteristics of developed immunosensors were investigated in reaction with microcystin-LR, and PSA. The calculated detection limit for analytes depended on the properties of antibodies. The detection limit for microcystin-LR was 10 ng mL(-1) and for PSA 0.01 ng mL(-1). The non-specific binding of analytes to synthesised polymers was very low. The polymer-coated chips were stored for up to 2 months without any noticeable deterioration in their ability to react with proteins. These findings make this new polymer very promising for the development of low-cost, easy to prepare and sensitive biosensors. (C) 2008 Elsevier B.V. All rights reserved.
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| 43. |
- Kyprianou, Dimitris, et al.
(författare)
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The application of polythiol molecules for protein immobilisation on sensor surfaces
- 2010
-
Ingår i: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 25:5, s. 1049-1055
-
Tidskriftsartikel (refereegranskat)abstract
- The immobilisation of bio-receptors on transducer surfaces is a key step in the development of biosensors. The immobilisation needs to be fast, cheap and most importantly should not affect the biorecognition activity of the immobilised receptor. The development of a protocol for biomolecule immobilisation onto a surface plasmon resonance (SPR) sensor surface using inexpensive polythiol compounds is presented here. The method used here is based on the reaction between primary amines and thioacetal groups, formed upon reaction of o-phthaldialdehyde (OPA) and thiol compounds. The self-assembled thiol monolayers were characterised using contact angle and XPS. The possibility to immobilise proteins on monolayers was assessed by employing BSA as a model protein. For the polythiol layers exhibiting the best performance, a general protocol was optimised suitable for the immobilisation of enzymes and antibodies such as anti-prostate specific antigen (anti-PSA) and anti Salmonella typhimurium. The kinetic data was obtained for PSA binding to anti-PSA and for S. typhimurium cells with a detection limit of 5 x 10(6) cells mL(-1) with minimal non-specific binding of other biomolecules. These findings make this technique a very promising alternative for amine coupling compared to peptide bond formation. Additionally, it offers opportunity for immobilising proteins (even those with low isoelectric point) on neutral polythiol layers without any activation step. (C) 2009 Elsevier B.V. All rights reserved.
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| 44. |
- Li, Songjun, et al.
(författare)
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‘On/off’-switchable catalysis by a smart enzyme-like imprinted polymer
- 2011
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Ingår i: Journal of Catalysis. - : Elsevier. - 0021-9517 .- 1090-2694. ; 278:2, s. 173-180
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Tidskriftsartikel (refereegranskat)abstract
- ‘On/off’-switchable catalysis by a smart enzyme-like imprinted polymer is reported. This unique imprinted polymer was composed of poly(N-isopropylacrylamide)-containing p-nitrophenyl phosphate-imprinted networks that exhibited temperature-dependent hydrophilicity/hydrophobicity. At a relatively low temperature (such as 20 °C), this polymer was capable of vigorous catalysis for the hydrolysis of p-nitrophenyl acetate due to its hydrophilic networks, which enabled access to the imprinted framework. On the contrary, at higher temperatures (such as 40 °C), this polymer demonstrated poor catalysis resulting from its dramatically increased hydrophobicity, which inhibited access to the imprinted sites. Unlike previously reported imprinted polymers which lack adjustable networks, this novel imprinted polymer employed thermosensitive poly(N-isopropylacrylamide) networks, thus enabling the switchable catalysis.
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| 45. |
- Meng, Lingyin, 1991-, et al.
(författare)
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Bi-functional sulphonate-coupled reduced graphene oxide as an efficient dopant for a conducting polymer with enhanced electrochemical performance
- 2020
-
Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry. - 2050-7526 .- 2050-7534. ; 8:37, s. 12829-12839
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Tidskriftsartikel (refereegranskat)abstract
- The rapidly emerging field of organic bioelectronics has witnessed the wide use of conducting polymers (CPs) to fabricate advanced chemically modified electrodes (CMEs) for biosensors and biomedical devices. The electrochemical performance of the CPs in such devices is closely related to the quality and physiochemical nature of the dopants. A bi-functional graphene oxide derivative with high reduction degree and negatively-charged sulphonate functionality, i.e. sulphonate-coupled reduced graphene oxide (S-RGO), was developed and used as an efficient dopant for a CP with enhanced electrochemical performance. The S-RGO was synthesised via a facile one-pot hydrothermal reaction using 4-hydrazinobenzosulphonic acid (4-HBS) as reductant and sulphonate precursor simultaneously. The resulting S-RGO possesses high aqueous dispersion stability (more than 6 months), high electrical conductivity (1493.0 S m−1) and sulphonate functionality. Due to these specific properties, S-RGO demonstrated improved electropolymerisation efficiency for poly(3,4-ethylenedioxythiophene) (PEDOT) proving an effective dopant for the preparation of a PEDOT:S-RGO film (5 mC) with faster polymerisation time (37 s) compared to the conventional 2D dopants GO (PEDOT:GO, 129 s) and RGO (PEDOT:RGO, 66 s). The resulting PEDOT:S-RGO appeared as a homogenous film with uniformly distributed S-RGO dopant, low equivalent series resistance and low charge transfer resistance. Moreover, the electrochemical transduction performance of the PEDOT:S-RGO interface was evaluated with 4 different analytes, including ferric/ferrocyanide redox probe, dopamine, nicotinamide adenine dinucleotide and hydrogen peroxide. As a result of the synergistic effect of S-RGO and PEDOT, the PEDOT:S-RGO demonstrated enhanced electrochemical performance with respect to faster electrode kinetics (smaller ΔEp), ∼2 and ∼4 times increased current responses, and lower peak potentials compared to PEDOT:GO and PEDOT:RGO. This bi-functional S-RGO dopant combined the advantages of conventional GO and RGO to deliver sulphonate functionality and high conductivity for the preparation of advanced PEDOT interface with improved electrochemical performance, that could potentially be applied for applications in electrochemical sensors, biosensors and bioelectronic devices.
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| 46. |
- Meng, Lingyin, 1991-, et al.
(författare)
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Soft and flexible material-based affinity sensors
- 2020
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Ingår i: Biotechnology Advances. - : Elsevier BV. - 0734-9750 .- 1873-1899. ; 39
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Forskningsöversikt (refereegranskat)abstract
- Recent advances in biosensors and point-of-care (PoC) devices are poised to change and expand the delivery of diagnostics from conventional lateral-flow assays and test strips that dominate the market currently, to newly emerging wearable and implantable devices that can provide continuous monitoring. Soft and flexible materials are playing a key role in propelling these trends towards real-time and remote health monitoring. Affinity biosensors have the capability to provide for diagnosis and monitoring of cancerous, cardiovascular, infectious and genetic diseases by the detection of biomarkers using affinity interactions. This review tracks the evolution of affinity sensors from conventional lateral-flow test strips to wearable/implantable devices enabled by soft and flexible materials. Initially, we highlight conventional affinity sensors exploiting membrane and paper materials which have been so successfully applied in point-of-care tests, such as lateral-flow immunoassay strips and emerging microfluidic paper-based devices. We then turn our attention to the multifarious polymer designs that provide both the base materials for sensor designs, such as PDMS, and more advanced functionalised materials that are capable of both recognition and transduction, such as conducting and molecularly imprinted polymers. The subsequent content discusses wearable soft and flexible material-based affinity sensors, classified as flexible and skin-mountable, textile materials-based and contact lens-based affinity sensors. In the final sections, we explore the possibilities for implantable/injectable soft and flexible material-based affinity sensors, including hydrogels, microencapsulated sensors and optical fibers. This area is truly a work in progress and we trust that this review will help pull together the many technological streams that are contributing to the field.
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| 47. |
- Newman, Jeffrey D., et al.
(författare)
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Biosensors : principles and practice
- 1992
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Ingår i: Essays in Biochemistry. - : Portland Press. - 0071-1365 .- 1744-1358. ; 27, s. 147-159
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Forskningsöversikt (refereegranskat)
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| 48. |
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| 49. |
- Ozgur, Erdogan, et al.
(författare)
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Lanthanide [Terbium(III)]-Doped Molecularly Imprinted Nanoarchitectures for the Fluorimetric Detection of Melatonin
- 2020
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Ingår i: Industrial & Engineering Chemistry Research. - : AMER CHEMICAL SOC. - 0888-5885 .- 1520-5045. ; 59:36, s. 16068-16076
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Tidskriftsartikel (refereegranskat)abstract
- Polymerizable terbium(III) complex-based fluorescent molecular imprinted smart nanoparticles were synthesized for the quantitative determination of potential metabolic destitution biomarkers. Melatonin has been reported to be one of the key factors in seasonal affective disorder (SAD) and was chosen as a model metabolite to demonstrate a novel molecularly imprinted polymer (MIP) nanoparticle sensor. We exploited lanthanide ion complexes in our biosensing platforms due to their deeper penetration ability, negligible autofluorescence, lack of photobleaching and photoblinking, and their sharp absorption and emission bands, extreme photostability, and long lifetime. Given the high affinity of lanthanide ions for carboxylic acid groups, we used two amino acid-based functional monomers, N-methacryloyl-L-tryptophan and N-methacryloyl-L-aspartic acid, to coordinate terbium-(III) ions and melatonin, respectively. The fluorescent MIP nanoparticles were synthesized using a miniemulsion polymerization technique after forming complexes between terbium(III):MA-Asp and melatonin:MATrp molecules. Due to the polymerizability of lanthanide complexes, they were readily inserted into the polymeric chain, which enabled homogeneous distribution as well as closer orientation to the imprinted cavities for selective melatonin recognition.
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| 50. |
- Palleschi, G., et al.
(författare)
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Amperometric tetrathiafulvalene-mediated lactate electrode using lactate oxidase absorbed on carbon foil
- 1990
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 234:2, s. 459-463
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The features of a new sensor for determining l-lactate are reported. The enzyme lactate oxidase and the mediator, tetrathiafulvalene (TTF), are absorbed on carbon foil disks previously bonded onto the ends of glass tubes. Linear calibration graphs were obtained in the range 10−4−10−3 M with physiological phosphate buffer (pH 7.35) and at 30°C with a response time of a few seconds. Calibration graphs in the range 10−3−10−2 M were also obtained and the difference in response times between these two ranges were investigated. The results are promising for assembling disposable lactate sensors for in vitro or for in or ex vivo measurements.
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