Near-Infrared Signal-Based Sensor Platform with Wireless Data Transmission System for Accurate Detection of Infectious Disease Virus

Luminescent nanomaterial-based Lateral flow immunoassay (LFA) is widely used in on-site detection of infectious virus. Foot-and-mouth disease virus (FMDV) is a highly contagious infectious disease virus that can be spread over long distanced in the air. The keys for reducing the risk of infectious disease spread and economic damage are; 1) rapid and sensitive on-site detection, and 2) real-time surveillance and remote monitoring in the field. However, on-site saliva samples from livestock are considerably opaque due to the high levels of contaminants and biological components such as food, feces, soil, and blood. These interfering agents in clinical saliva samples interfere with the detection of colorimetric signals of LFA by the naked eye. Commercial gold nanoparticle-based LFA, whose excitation and emission are located in the visible region, is limited in their low sensitivity affected by the background interference in the opaque sample. Here, we report a high sensitive detection of FMDVs in clinical samples and the wireless monitoring system of FMD's outbreak. We introduced near-infrared (NIR)-to-NIR upconversion nanoparticles (UCNPs) as a nanoprobe of the LFA platform for background-free sensitive detection of FMDV. The NIR-to-NIR UCNPs are effective in minimizing the interference noise of opaque biological samples because the interfering agents in the samples have low autofluorescence, scattering, and absorption within the NIR window. This NIR-to-NIR nanoprobe shows stable emission intensity at 800 nm without being disturbed by interfering agents under 980 nm excitation. The sensitivity of LFA assembled with NIR-to-NIR nanoprobe (denoted as NIR signal LFA) was improved in opaque clinical samples. The NIR signal LFA has 32-fold lower limit of detection (LOD) compared to a commercial gold nanoparticle-based FMDV LFA for assay using live FMDVs for all 7 serotypes. 148 clinical samples including saliva and vesicular fluid samples were used to validate the sensing performance of NIR signal LFA for FMDVs. The NIR signal LFA successfully detected FMDVs in clinical samples with a high sensitivity of 96.9%, and a specificity of 100.0%. In addition, information such as virus-detection results and infection location were successfully stored and transmitted in real-time through an online server. The developed platform is promising for establishing a quarantine linkage system that can effectively prevent and control the spread of FMDV at an early stage.