| 1. |
- Chinnasamy, Thiruppathiraja, et al.
(författare)
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A lateral flow paper microarray for rapid allergy point of care diagnostics
- 2014
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 139:10, s. 2348-2354
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing need for multiplexed specific IgE tests that can accurately evaluate patient sensitization profiles. However, currently available commercial tests are either single/low-plexed or require sophisticated instrumentation at considerable cost per assay. Here, we present a novel convenient lateral flow microarray-based device that employs a novel dual labelled gold nanoparticle-strategy for rapid and sensitive detection of a panel of 15 specific IgE responses in 35 clinical serum samples. Each gold nanoparticle was conjugated to an optimized ratio of HRP and anti-IgE, allowing significant enzymatic amplification to improve the sensitivity of the assay as compared to commercially available detection reagents. The mean inter-assay variability of the developed LFM assay was 12% CV, and analysis of a cohort of clinical samples (n = 35) revealed good general agreement with ImmunoCAP, yet with a varying performance among allergens (AUC = [0.54-0.88], threshold 1 kU). Due to the rapid and simple procedure, inexpensive materials and read-out by means of a consumer flatbed scanner, the presented assay may provide an interesting low-cost alternative to existing multiplexed methods when thresholds > 1 kU are acceptable.
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| 2. |
- Chinnasamy, Thiruppathiraja, et al.
(författare)
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Point-of-Care Vertical Flow Allergen Microarray Assay : Proof of Concept
- 2014
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 60:9, s. 1209-1216
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Sophisticated equipment, lengthy protocols, and skilled operators are required to perform protein microarray-based affinity assays. Consequently, novel tools are needed to bring biomarkers and biomarker panels into clinical use in different settings. Here, we describe a novel paper-based vertical flow microarray (VFM) system with a multiplexing capacity of at least 1480 microspot binding sites, colorimetric readout, high sensitivity, and assay time of < 10 min before imaging and data analysis. METHOD: Affinity binders were deposited on nitrocellulose membranes by conventional microarray printing. Buffers and reagents were applied vertically by use of a flow controlled syringe pump. As a clinical model system, we analyzed 31 precharacterized human serum samples using the array system with 10 allergen components to detect specific IgE reactivities. We detected bound analytes using gold nanoparticle conjugates with assay time of <= 10 min. Microarray images were captured by a consumer-grade flatbed scanner. RESULTS: A sensitivity of 1 ng/mL was demonstrated with the VFM assay with colorimetric readout. The reproducibility (CV) of the system was < 14%. The observed concordance with a clinical assay, Immuno-CAP, was R-2 = 0.89 (n = 31). CONCLUSIONS: In this proof-of-concept study, we demonstrated that the VFM assay, which combines features from protein microarrays and paper-based colorimetric systems, could offer an interesting alternative for future highly multiplexed affinity point-of-care testing.
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| 3. |
- Chinnasamy, Thiruppathiraja, et al.
(författare)
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Towards paper-based point of care affinity proteomics
- 2014
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Ingår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014. - : Chemical and Biological Microsystems Society. - 9780979806476 ; , s. 64-66
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Konferensbidrag (refereegranskat)abstract
- Affinity-based methods such as protein microarrays have come to complement conventional mass/charge-based techniques for proteomic characterization of biological samples. Simultaneous measurement of hundreds or even thousands of serum biomarkers such as antibodies, antigens and other proteins may greatly improve the diagnostic accuracy in a variety of conditions such as autoimmune disorders, infections and several cancers. However, today's technologies for affinity proteomics are cumbersome, require expensive equipment and skilled operators. Here, we present two novel paper-based techniques developed in our lab that aim to bridge the gap between highly multiplexed affinity proteomics and point of care testing.
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| 4. |
- Krishnan, Srinivasan, et al.
(författare)
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Dual labeled Ag@SiO2 core-shell nanoparticle based optical immunosensor for sensitive detection of E. coli
- 2014
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Ingår i: Materials science & engineering. C, biomimetic materials, sensors and systems. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 45, s. 337-342
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Tidskriftsartikel (refereegranskat)abstract
- An optical nanobiosensor is presented using a fluorescent dye and anti-E. coli McAb anchored Ag@Silica core shell nanoparticles, for rapid and sensitive Escherichia coli detection in environmental samples. The synthesized dual labeled core shell (DLCS) nanoparticle shows intense fluorescence at 620 nm in solution, having a narrow emission with full width at half maxima (FWHM) of 10 nm, as a prerequisite to develop a sensitive detection platform for various biosensing applications. The specific E. coli was captured using an anti-E. coli antibody functionalized quartz glass, followed by a treatment with DLCS, where the photoluminescence spectroscopy was used to detect the target pathogen. The fabrication of the quartz glass based optical-immunosensor was monitored, and the results show changes in the photoluminescent patterns, which substantiate that varied species were immobilized on the surface of the antibody modified quartz glass. Consequently, the optical immunosensor demonstrated specificity and improved sensitivity, as compared to the customary methods, and was able to detect as low as 5 CFU/mL. The developed DLCS based optical immunosensor was evaluated with environmental water samples, which showed acceptable precision, reproducibility and stability, and could be readily applied to the routine monitoring of pathogenic microorganisms in the environmental samples, and most importantly, demonstrate the potential of a prototype development of a simple and inexpensive diagnostic technique.
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| 5. |
- Srinivasan, K., et al.
(författare)
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Sensitive detection of C. parvum using near infrared emitting Ag2S@silica core-shell nanospheres
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:107, s. 62399-62403
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Tidskriftsartikel (refereegranskat)abstract
- An optical immunosensor was developed using anti-oocysts McAb immobilized near-infrared (NIR) emitting Ag2S@silica core-shell nanospheres for the detection of C. parvum in water. The formation of the core Ag2S and the SiO2 shell over the core was confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The optical properties of the nanostructures were determined by UV-Vis spectroscopy and photoluminescence (PL) studies. The core-shell Ag2S@silica nanospheres exhibited an intense emission peak at 896 nm which falls in the biological window. TEM images confirm the presence of a uniform core-shell structure, with a Ag2S core with an average size of 80 nm, and a silica shell with a thickness of 40-50 nm. The C. parvum antibody anti-oocysts McAb immobilized Ag2S@silica nanoparticles were used as detector probes and these biosensors exhibited excellent analytical performance toward the detection of C. parvum, with detection limits of 10 oocysts per mL with a minimal assay period.
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