A microfluidic platform for the ultrasensitive detection of human enterovirus 71

Abstract

A microfluidic platform integrated with two generated monoclonal antibodies (mAbs) was innovatively fabricated for ultrasensitive detection of enterovirus 71 (EV71). To date, this is the first report on EV71 detection using a microfluidic chip-based immunoassay. The mAbs 1F4 and 2H2 against the major capsid protein VP1 of EV71 were conjugated with carboxyl-functionalized magnetic beads (MBs) and carboxyl-functionalized quantum dots (QDs), respectively. MB-conjugated mAbs separated VP1 from samples, while QD-conjugated mAbs provided fluorescence detection signals and formed a sandwich structure. The monolayer of MBs and QDs captured the VP1 sandwich structure showed stronger fluorescence signal in the microfluidic channel, which could be directly evaluated by fluorescence intensity in response to 365 nm ultraviolet (UV) excitation. The limit of detection (LOD) of the microfluidic platform for VP1 was 10 pg mL−1, which was a 31-fold increase compared to sandwich enzyme-linked immunosorbent assay (ELISA, 310 pg mL−1) using identical antibodies. The microfluidic platform performed well with clinical samples, especially for fecal samples with complex compositions and impurities. The assay is quick to perform (within 30 min), and apparently requires just one syringe without other complex liquid flow system, making it is easy to operate and more suitable for on-site detection and future commercial application.

Keywords

• EV71
• Microfluidic platform
• Microfluidic immunoassay, Ultrasensitive detection