Integrated NFC power source for zero on-board power in fluorescent paper-based lateral flow immunoassays

Abstract

A lab-on-chip vehicle was explored combining RF near field communication (NFC) harvested power and light sources for paper-based lateral flow immunoassay systems (LFIA) with quantum dots (QD) as fluorophores. Such a vehicle has potential applications in point-of-care systems requiring high sensitivity while also being low-cost, disposable and easy to use. Micro-LEDs which provided the excitation source for the test line of a QD-LFIA were surface mounted on plastic substrates using a printed hybrid electronics approach for the fabrication of power harvesting NFC antenna, chip assembly and electronics integration with the LFIA strip. The LFIA is a rotavirus assay kit with Au nanoparticles into which QDs emitting at 655 nm were also incorporated. A digital camera was used for detecting the fluorescence from QDs and the reflected signal from Au NPs. The signals were compared using grayscale analysis. The NFC-powered LED light source integrated with the QD-LFIA demonstrated ~9× higher sensitivity compared to conventional Au-NP based assays. Such an integrated system can be potentially mass manufactured using roll-to-roll processing making the device cost effective, as well as having high sensitivity.