Single-Particle Enzyme Activity Assay with Spectral-Resolved Dark-Field Optical Microscopy.

08:00 EDT 12th April 2019 | BioPortfolio

Summary of "Single-Particle Enzyme Activity Assay with Spectral-Resolved Dark-Field Optical Microscopy."

In clinical assay, enzymes are essential biomarkers for human disease diagnosis. In this work, a spectral-resolved single-particle detection (SPD) method is introduced to quantify alkaline phosphatase (ALP) activity in human serum with supraparticles (SPs) based on MnO2 modified gold nanoparticle (denoted as GNP@MnO2 SPs) as the probe. In the presence of ALP, 2-phospho-L-ascorbic acid trisodium salt (AA2P) can be hydrolyzed into L-ascorbic acid (AA), which serves as a good reduction agent to trigger the decomposition of MnO2 shell on GNPs surface. Given that trace amount of ALP exists, noticeable scattering color change can be detected at single-particle level due to the sensitive localized surface plasmon resonance (LSPR) effect from GNPs. With spectral-resolved dark-field optical microscopy (DFM), a linear dynamic range of 0.06-2.48 mU/mL (R2 = 0.99) and a very low limit of detection (LOD) 5.8 µU/mL for ALP assay is readily achieved, which is more sensitive over the methods based on ensemble sample measurement. As a consequence, this strategy opens a new avenue for the design of ultra-sensitive detection method for disease-correlated biomarker diagnosis in the future.


Journal Details

This article was published in the following journal.

Name: Analytical chemistry
ISSN: 1520-6882


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