Electrically Readable Lateral Flow Assay Using Organic Transistors for Diagnostic Applications

Electrolyte-gated organic field-effect transistors (EGOFETs) are emerging as powerful, ultrasensitive label-free biosensors, but their applicability as portable diagnostic tools remains constrained by poor microfluidic miniaturization and complex multi-step ex situ assays. Simultaneously, paper-based lateral flow (LF) immunoassays hold significant relevance for integrated diagnostic applications in the market, but are limited by the low sensitivity of optical detection. To address these challenges, a simple EGOFET integrated with LF paper fluidics are reported to obtain a reusable, highly portable, and cost-effective point-of-care (PoC) test with rapid results (≈20-30 min). The test is validated for Human Immunoglobulin G detection, achieving a wide linear range, high selectivity, reproducibility, and a low limit of detection of 0.1 fm. The portability of the system is demonstrated in a designed prototype with a miniaturized electronic reader, operating via an adapted USB-connected smart device. This work fulfills the requirements of low-cost PoC tests and offers a foundation for the next generation of digital LF assays.