A serological point-of-care test for Zika virus detection and infection surveillance using an enzyme-free vial immunosensor with a smartphone

Zika virus (ZIKV) is a mosquito-borne flavivirus (FLAV) that emerged in Brazil in 2015 and has rapidly spread to more than 50 countries worldwide. However, early, accurate, and specific point-of-care (POC) diagnosis of ZIKV is very difficult because most infected patients are asymptomatic or display nonspecific symptoms similar to those of other viral infections, and most of the analysis also requires instruments. Herein, an instrument-free ZIKV POC test using a drop of blood comprising a vial immunosensor, artificial nanozyme platinum/gold core-shell nanoparticles (Pt@Au NPs) as a signal probe, and a smartphone was developed to specifically detect ZIKV without cross-reaction with other FLAVs. A high sensitivity of 1 pg/mL ZIKV, desirable specificity, data storage, and geographic location surveillance were simultaneously achieved for the proposed POC test. Our POC test suitably met the urgent needs of ports of entry, airports, and endemic regions with stressed resources, as well as strict clinical requirements for ZIKV detection.