Immuno-gold silver staining assays on capillary-driven microfluidics for the detection of malaria antigens.
Immuno-gold silver staining assays on capillary-driven microfluidics for the detection of malaria antigens.
Biomed Microdevices. 2019 Feb 27;21(1):24
Authors: Pham NM, Rusch S, Temiz Y, Beck HP, Karlen W, Delamarche E
Abstract
Accurate and affordable rapid diagnostic tests (RDTs) are indispensable but often lacking for many infectious diseases. Specifically, there is a lack of highly sensitive malaria RDTs that can detect low antigen concentration at the onset of infection. Here, we present a strategy to improve the sensitivity of malaria RDTs by using capillary-driven microfluidic chips and combining sandwich immunoassays with electroless silver staining. We used 5 μm fluorescent beads functionalized with capture antibodies (cAbs). These beads are self-assembled by capillary action in recessed "bead lanes", which cross the main flow path of chips microfabricated in Si and SU-8. The binding of analytes to detection antibodies (dAbs) and secondary antibodies (2ndAbs) conjugated to gold nanoparticles (NPs) allows the formation of a silver film on the beads. Such silver film masks the fluorescent core of the bead inversely proportional to the concentration of antigen in a sample. We illustrate this method using the recombinant malaria antigen Plasmodium falciparum histidine-rich-protein 2 (rPfHRP2) spiked in human serum. This antigen was a recombinant HRP2 protein expressed in Escherichia coli, which is also the standard reference mat...
Source: Biomedical Microdevices - Category: Biomedical Engineering Authors: Pham NM, Rusch S, Temiz Y, Beck HP, Karlen W, Delamarche E Tags: Biomed Microdevices Source Type: research
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