| 1. |
- Abellan-Flos, Marta, et al.
(author)
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QCM sensing of multivalent interactions between lectins and well-defined glycosylated nanoplatforms
- 2019
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In: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 139
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Journal article (peer-reviewed)abstract
- Quartz crystal microbalance (QCM) methodology has been adopted to unravel important factors contributing to the "cluster glycoside effect" observed in carbohydrate-lectin interactions. Well-defined, glycosylated nanostructures of precise sizes, geometries and functionalization patterns were designed and synthesized, and applied to analysis of the interaction kinetics and thermodynamics with immobilized lectins. The nanostructures were based on Borromean rings, dodecaamine cages, and fullerenes, each of which carrying a defined number of carbohydrate ligands at precise locations. The synthesis of the Borromeates and dodecaamine cages was easily adjustable due to the modular assembly of the structures, resulting in variations in presentation mode. The binding properties of the glycosylated nanoplatforms were evaluated using flow-through QCM technology, as well as hemagglutination inhibition assays, and compared with dodecaglycosylated fullerenes and a monovalent reference. With the QCM setup, the association and dissociation rate constants and the associated equilibrium constants of the interactions could be estimated, and the results used to delineate the multivalency effects of the lectin-nanostructure interactions.
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| 2. |
- Ashaduzzaman, M., et al.
(author)
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Studies on an on/off-switchable immunosensor for troponin T
- 2015
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In: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 73
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Journal article (peer-reviewed)abstract
- Regeneration is a key goal in the design of immunosensors. In this study, we report the temperature-regulated interaction of N-isopropylacrylamide (PNIPAAm) functionalised cardiac troponin T (cTnT) with anti-cTnT. Covalently bonded PNIPAAm on an anti-cTnT bioelectrode showed on/off-switchability, regeneration capacity and temperature triggered sensitivity for cTnT. Above the lower critical solution temperature (LCST), PNIPAAm provides a liphophilic microenvironment with specific volume reduction at the bioelectrode surface, making available binding space for cTnT, and facilitating analyte recognition. Computational studies provide details about the structural changes occurring at the electrode above and below the LCST. Furthermore, free energies associated with the binding of cTnT with PNIPAAm at 25 (δGcoil=-6.0Kcal/mole) and 37°C (δGglobular=-41.0kcal/mole) were calculated to elucidate the interaction and stability of the antigen-antibody complex. The responsiveness of such assemblies opens the way for miniaturised, smart immuno-technologies with 'built-in' programmable interactions of antigen-antibody upon receiving stimuli.
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| 3. |
- Azzouzi, Sawsen, et al.
(author)
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An integrated dual functional recognition/amplification bio-label for the one-step impedimetric detection of Micro-RNA-21
- 2017
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In: Biosensors & bioelectronics. - : ELSEVIER ADVANCED TECHNOLOGY. - 0956-5663 .- 1873-4235. ; 92, s. 154-161
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Journal article (peer-reviewed)abstract
- Alteration in expression of miRNAs has been correlated with different cancer types, tumour stage and response to treatments. In this context, a structurally responsive oligonucleotide-based electrochemical impedimetric biosensor has been developed for the simple and sensitive detection of miRNA-21. A highly specific biotinylated DNA/LNA molecular beacon (MB) probe was conjugated with gold nanoparticles (AuNPs) to create an integrated, dual function bio-label (biotin-MB-AuNPs) for both biorecognition and signal generation. In the presence of target miRNA-21, hybridisation takes place resulting in the "activation" of the biotin-MB; this event makes the biotin group, which was previously "protected" by the steric hindrance of the MB stem-loop structure, accessible. The activated biotin-MB-AuNPs/miRNA complexes become available for capture, via supramolecular interaction, onto a nentravidin-modified electrode for electrochemical transduction. The binding event results in a decrease of the charge transfer resistance at the working electrode/electrolyte interface. The biosensor responded linearly in the range 1-1000 pM of miRNA-21, with a limit of detection of 0.3 pM, good reproducibility (Relative Standard deviation (RSD) =3.3%) and high selectivity over other miRNAs (i.e. miRNA221 and miRNA-205) sequences. Detection of miRNA-21 in spiked serum samples at clinically relevant levels (low pM range) was also demonstrated, thus illustrating the potential of the biosensor for point-of-care clinical applications. The proposed biosensor design, based on the combination of a neutravidin transducing surface and the dual-function biotin-MB-AuNPs bio-label, provides a simple and robust approach for detection of short-length nucleic acid targets, such as miRNAs.
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| 4. |
- Bagheryan, Z., et al.
(author)
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Diazonium-based impedimetric aptasensor for the rapid label-free detection of Salmonella typhimurium in food sample
- 2016
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In: Biosensors & bioelectronics. - : Elsevier Ltd. - 0956-5663 .- 1873-4235. ; 80, s. 566-573
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Journal article (peer-reviewed)abstract
- Fast and accurate detection of microorganisms is of key importance in clinical analysis and in food and water quality monitoring. Salmonella typhimurium is responsible for about a third of all cases of foodborne diseases and consequently, its fast detection is of great importance for ensuring the safety of foodstuffs.We report the development of a label-free impedimetric aptamer-based biosensor for S. typhimurium detection. The aptamer biosensor was fabricated by grafting a diazonium-supporting layer onto screen-printed carbon electrodes (SPEs), via electrochemical or chemical approaches, followed by chemical immobilisation of aminated-aptamer. FTIR-ATR, contact angle and electrochemical measurements were used to monitor the fabrication process. Results showed that electrochemical immobilisation of the diazonium-grafting layer allowed the formation of a denser aptamer layer, which resulted in higher sensitivity. The developed aptamer-biosensor responded linearly, on a logarithm scale, over the concentration range 1×101 to 1×108 CFU mL-1, with a limit of quantification (LOQ) of 1×101 CFU mL-1 and a limit of detection (LOD) of 6 CFU mL-1. Selectivity studies showed that the aptamer biosensor could discriminate S. typhimurium from 6 other model bacteria strains. Finally, recovery studies demonstrated its suitability for the detection of S. typhimurium in spiked (1×102, 1×104 and 1×106 CFU mL-1) apple juice samples.
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| 5. |
- Bobrowski, Tim, et al.
(author)
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Rechargeable, flexible and mediator-free biosupercapacitor based on transparent ITO nanoparticle modified electrodes acting in mu M glucose containing buffers
- 2018
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In: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 101, s. 84-89
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Journal article (peer-reviewed)abstract
- We present a transparent and flexible self-charging biosupercapacitor based on an optimised mediator- and membrane-free enzymatic glucose/oxygen biofuel cell. Indium tin oxide (ITO) nanoparticles were spray-coated on transparent conducting ITO supports resulting in a flocculent, porous and nanostructured electrode surface. By this, high capacitive currents caused by an increased electrochemical double layer as well as enhanced catalytic currents due to a higher number of immobilised enzyme molecules were obtained. After a chemical pretreatment with a silane derivative, bilirubin oxidase from Myrothecium verrucaria was immobilized onto the ITO nanostructured electrode surface under formation of a biocathode, while bioanodes were obtained by either immobilisation of cellobiose dehydrogenase from Corynascus thermophilus or soluble PQQ-dependent glucose dehydrogenase from Acinetobacter calcoaceticus. The latter showed a lower apparent K-M value for glucose conversion and higher catalytic currents at mu M glucose concentrations. Applying the optimised device as a biosupercapacitor in a discontinuous charge/discharge mode led to a generated power output of 0.030 mW/cm(2) at 50 mu M glucose, simulating the glucose concentration in human tears. This represents an enhancement by a factor of 350 compared to the power density obtained from the continuously operating biofuel cell with a maximum power output of 0.086 mu W/cm(2) under the same conditions. After 17 h of charging/discharging cycles a remarkable current enhancement was still measured. The entire device was transferred to flexible materials and applied for powering a flexible display showing its potential applicability as an intermittent power source in smart contact lenses.
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| 6. |
- Borsa, Baris A, et al.
(author)
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Staphylococcus aureus detection in blood samples by silica nanoparticle-oligonucleotides conjugates.
- 2016
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In: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 86, s. 27-32
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Journal article (peer-reviewed)abstract
- A fast, specific and sensitive homogeneous assay for Staphylococcus aureus detection was developed by measuring the activity of secreted nuclease from the bacteria via a modified DNA oligonucleotide. As biosensor format, an effective system, Nanokeepers as previously reported, were used for triggered release of confined fluorophores, and hence specific detection of S. aureus on nuclease activity was obtained. The interference from blood components for fluorescent quantification was eliminated by a pre-purification by aptamer-functionalized silica magnetic nanoparticles. The reported assay system was exclusively formed by nucleic acid oligos and magnetic or mesoporous silica nanoparticles, that can be used on blood samples in a stepwise manner. The assay was successfully used as a sensing platform for the specific detection of S. aureus cells as low as 682 CFU in whole blood.
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| 7. |
- Cánovas, Rocio, et al.
(author)
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Modern creatinine (Bio)sensing : Challenges of point-of-care platforms
- 2019
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In: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 130, s. 110-124
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Research review (peer-reviewed)abstract
- The importance of knowing creatinine levels in the human body is related to the possible association with renal, muscular and thyroid dysfunction. Thus, the accurate detection of creatinine may indirectly provide information surrounding those functional processes, therefore contributing to the management of the health status of the individual and early diagnosis of acute diseases. The questions at this point are: to what extent is creatinine information clinically relevant?; and do modern creatinine (bio)sensing strategies fulfil the real needs of healthcare applications? The present review addresses these questions by means of a deep analysis of the creatinine sensors reported in the literature over the last five years. There is a wide range of techniques for detecting creatinine, most of them based on optical readouts (20 of the 33 papers collected in this review). However, the use of electrochemical techniques (13 of the 33 papers) is recently emerging in alignment with the search for a definitive and trustworthy creatinine detection at the point-of-care level. In this sense, biosensors (7 of the 33 papers) are being established as the most promising alternative over the years. While creatinine levels in the blood seem to provide better information about patient status, none of the reported sensors display adequate selectivity in such a complex matrix. In contrast, the analysis of other types of biological samples (e.g., saliva and urine) seems to be more viable in terms of simplicity, cross-selectivity and (bio)fouling, besides the fact that its extraction does not disturb individual's well-being. Consequently, simple tests may likely be used for the initial check of the individual in routine analysis, and then, more accurate blood detection of creatinine could be necessary to provide a more genuine diagnosis and/or support the corresponding decision-making by the physician. Herein, we provide a critical discussion of the advantages of current methods of (bio)sensing of creatinine, as well as an overview of the drawbacks that impede their definitive point-of-care establishment.
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| 8. |
- Carinelli, S., et al.
(author)
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Yoctomole electrochemical genosensing of Ebola virus cDNA by rolling circle and circle to circle amplification
- 2017
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In: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 93, s. 65-71
-
Journal article (peer-reviewed)abstract
- This work addresses the design of an Ebola diagnostic test involving a simple, rapid, specific and highly sensitive procedure based on isothermal amplification on magnetic particles with electrochemical readout. Ebola padlock probes were designed to detect a specific L-gene sequence present in the five most common Ebola species. Ebola cDNA was amplified by rolling circle amplification (RCA) on magnetic particles. Further re-amplification was performed by circle-to-circle amplification (C2CA) and the products were detected in a double-tagging approach using a biotinylated capture probe for immobilization on magnetic particles and a readout probe for electrochemical detection by square-wave voltammetry on commercial screen-printed electrodes. The electrochemical genosensor was able to detect as low as 200 ymol, corresponding to 120 cDNA molecules of L-gene Ebola virus with a limit of detection of 33 cDNA molecules. The isothermal double-amplification procedure by C2CA combined with the electrochemical readout and the magnetic actuation enables the high sensitivity, resulting in a rapid, inexpensive, robust and user-friendly sensing strategy that offers a promising approach for the primary care in low resource settings, especially in less developed countries.
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| 9. |
- Chen, Qun, et al.
(author)
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A biosensing strategy for the rapid detection and classification of antibiotic resistance.
- 2015
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In: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 73, s. 251-255
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Journal article (peer-reviewed)abstract
- Antibiotic resistance (AR) poses an ever growing threat to global public health. Methods are urgently needed that simplify and accelerate the clinical detection and classification of AR. Here we describe a function-based antibiotic resistance assay (FARA) biosensing strategy. The scheme comprises three key components: i) FARA directly measures the thermal signal generated from the catalytic break-down of antibiotics by AR enzymes, ii) a sample specific AR profile is created by analyzing a panel of antibiotics which enhances informational content and iii) meta-analysis of the AR profile database to correlate profiles with diagnosis, treatments and outcomes. In order to test the ability of the scheme to identify and classify AR, two well-studied antibiotic resistance enzymes, penicillinase and metallo-beta-lactamase (MBL), were profiled using a panel of 5 antibiotics: penicillin G, penicillin V, ampicillin, oxacillin and imipenem. The results show that the profiles of the two enzymes could easily detect AR and differentially classified these enzymes. More importantly, both enzymes showed a significant and distinct secondary catalytic profile, which dramatically increases informational content. FARA profiles can be generated and analyzed in 1h. FARA is a fast, simple, cost effective alternative for detecting and classifying AR. FARA will speed up AR detection and classification will allow more accurate individualized treatment. This will reduce the spread of resistance and personalized treatments will improve patient outcomes. Other potential applications of FARA technology are discussed, including the possibility of developing an in vitro blood model for studying AR.
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| 10. |
- Cipri, Andrea, et al.
(author)
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A novel bio-electronic tongue using different cellobiose dehydrogenases to resolve mixtures of various sugars and interfering analytes.
- 2015
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In: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 79, s. 515-521
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Journal article (peer-reviewed)abstract
- A novel application of cellobiose dehydrogenase (CDH) as sensing element for a Bioelectronic Tongue (BioET) system has been tested. In this work CDHs from various fungi, which exhibit different substrate specificities, were used to discriminate between lactose and glucose in presence of the interfering matrix compound Ca(2+) in various mixtures. This work exploits the advantage of an electronic tongue system with practically zero pre-treatment of samples and operation at low voltages in a direct electron transfer mode. The Artificial Neural Network (ANN) used in the BioET system to interpret the voltammetric data was able to provide a correct prediction of the concentrations of the analytes considered. Correlation coefficients in the comparison of obtained vs. expected concentrations were highly significant, especially for lactose (R(2)=0.975) and Ca(2+) (R(2)=0.945). This BioET application has a high potential especially for the food and dairy industry and also, if further miniaturised in screen printed format, for its in-situ use.
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