Quantitative Detection in Lateral Flow Immunoassay Using Integrated Organic Optoelectronics

A low cost, disposable point-of-care (POC) diagnostic device with integrated organic optoelectronic devices has been investigated for quantitative detection. The diagnostic component consists of a lateral flow immunoassay (LFIA) paper-based biosensor that uses capillary action for transportation of fluids. The absence of external fluid pumps and the low cost of materials utilized make LFIA a simple, inexpensive POC diagnostic device. For detection, the LFIA was integrated with organic optoelectronics devices on thin plastic sheets as a step toward a fully integrated lab-on-chip device. Organic semiconductor devices are suited for this purpose as they can be formed on many types of substrates and can have relatively large active area. For the light emitting component, phosphorescent green emitting organic light emitting diodes (OLED) have been used owing to their high brightness, while for the light detector an organic photodiode (OPD) that absorbs at green wavelengths has been used. Quantitative measurements were performed using optical transmission mode through the LFIA strip that forms red test and control lines by accumulation of gold nanoparticles (AuNP). In this configuration, the amount of transmitted light decreases as AuNPs accumulate on the test line, which directly correlates with the analyte concentration. This change in optical intensity results in a corresponding change in the measured OPD photocurrent. Initial quantification was obtained for 5 levels of rotavirus analyte. OLEDs and OPDs fabricated on plastic substrates were integrated within the LFIA chip to measure the intensity of line formation over a period of 30 min.