ABSTRACT
The success of controlling emerging infectious diseases relies on the fast development of robust, quantitative assays for point-of-care testing. Here a generalizable strategy is demonstrated for developing inexpensive, simple-to-use, and rapid diagnostics within a few weeks upon the identification of a new viral antigen. Using Ebola virus secreted glycoprotein (sGP) as a target, we design a new assay featuring nanobody-conjugated nanoparticles for rapid, electronic detection (Nano2RED). Nanobodies with the high affinity and specificity were generated by phage display screening of a high-quality combinatorial library (> 109) and site-specifically conjugated to gold nanoparticles (AuNPs) for in-solution colorimetric detection. Our assay can robustly detect the sGP protein from 10 pM to 100 nM in diluted serum and distinguish it from a membrane-anchored isoform, GP1,2, allowing the diagnosis of the viral infection stage. Additionally, a rapid assay protocol was established to decrease the assay time to a few minutes without compromising the accuracy. Lastly, this assay has been integrated with a portable semiconductor device with a digital readout and minimal training requirement for end users. Our method can be widely applied to the point-of-care testing of other infectious diseases.
Competing Interest Statement
The authors have declared no competing interest.
