rapid-nanoprobe-signal-enhancement-situ-gold-nanoparticle

Rapid Nanoprobe Signal Enhancement by <em>In Situ</em> Gold Nanoparticle Synthesis

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...

KTH Royal Institute of Technology

Highly multiplexed point of care tests could improve diagnostic accuracy and differential diagnostic capacity in for instance emergency medicine and low resource environments. Available technology platforms for POC biomarker detection are typically simplex or low-plexed, whereas common lab-based microarray systems allow for the simultaneous detection of thousands of DNA or protein biomarkers. In this study, we demonstrate a novel suspension particle array platform that utilizes 900 μm bricks for POC amenable colorimetric biomarker detection with an encoding capacity of over two million. Due to the mm-scale size, both the lithographic codes and colorimetric signals of individual particles can be visualized using a consumer grade office flatbed scanner, with a potential for simultaneous imaging of around 19 000 particles per scan. The analytical sensitivity of the assay was determined to be 4 ng mlusing an antibody model system. As a proof of concept, autoantibodies toward anoctamin 2 were detected in order to discriminate between multiple sclerosis plasma samples and healthy controls with p < 0.0001 and an inter-assay % CV of 9.44%.

Towards encoded particles for highly multiplexed colorimetric point of care autoantibody detection.

The introduction of nanomaterials as detection reagents has enabled improved sensitivity and facilitated detection in a variety of bioanalytical assays. However, high nanoprobe densities are typically needed for colorimetric detection and to circumvent this limitation several enhancement protocols have been reported. Nevertheless, there is currently a lack of universal, enzyme-free and versatile methods that can be readily applied to existing as well as new biosensing strategies. The novel method presented here is shown to enhance the signal of gold nanoparticles enabling visual detection of a spot containing <10 nanoparticles. Detection of Protein G on paper arrays was improved by a 100-fold amplification factor in under five minutes of assay time, using IgG-labelled gold, silver, silica and iron oxide nanoprobes. Furthermore, we show that the presented protocol can be applied to a commercial allergen microarray assay, ImmunoCAP ISAC sIgE 112, attaining a good agreement with fluorescent detection when analysing human clinical samples.

Article	Year
Towards encoded particles for highly multiplexed colorimetric point of care autoantibody detection. Lab on a chip\| PubMed ID: 28102419	2017
Rapid signal enhancement method for nanoprobe-based biosensing. Scientific reports\| PubMed ID: 28754966	2017

Gustav Svedberg

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