Paper-based Point-of-Care Detection of L-lactate Shines by Employing a Stronger Emitting Luminol

Monday, March 08, 2021: 3:25 PM - 3:45 PM

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Description

Chemiluminescence (CL) can provide superior assay sensitivity due to its low natural background signals. It lends itself well for point-of-care (POC) applications for low concentration analytes as no excitation or electrochemical reaction is needed for light emission. Since POC tests must work with aqueous solutions, our hypothesis was that a highly water-soluble derivative of the standard CL reagent luminol will improve their limits of detection. m-Carboxy luminol was therefore studied in comparison to luminol for strategies based on the quantification of its oxidant H2O2, or by the luminophore itself. In the latter case, its inherently higher relative quantum yield of almost 5% and higher hydrophilicity lead to extraordinary signal-to-noise ratios of over 60 in comparison to at most 16 for luminol. Since also all catalysts proved the superior performance of m-carboxy luminol, it was used for the development of an L-lactate paper-based POC for sweat analysis. Here, a lower limit of detection and an order of magnitude increased dynamic range in direct comparison to standard luminol was obtained. Furthermore, the broad clinically relevant range for L-lactate of three orders of magnitude is easily covered and a detection platform, equaling standard laboratory test system in accuracy and resolution, is provided. While a standard CCD camera was used for signal recording, POC applications can benefit from the use of a normal smartphone camera. The results obtained here suggest that a paper-based microfluidic CL test system can become the POC platform for the many CL-based standard analytical assays performed in microtiter plates, as microarrays or other more complex detection strategies.

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Additional Info

Keywords: Please select up to 4 keywords ONLY:
Biomedical,Enzyme Assays,Fluorescence and Luminescence