Biosensors based on organic transistors for intraoral biomarker detection

Intraoral biomarkers are important indicators for the diagnosis and prediction of oral and systemic diseases. Among various intraoral biomarkers, the biomarkers in saliva have been the main focus of research, due to their abundance, non-invasiveness, and correlation with health status. Nonetheless, detecting low-abundance intraoral biomarkers poses significant challenges, and the conventional assays are unsuitable for swift large-scale analysis due to their complex procedures. Hence, an immediate demand arises for innovative methods to supplant traditional assay techniques. Organic transistor-based biosensors have emerged as promising devices for the detection of these intraoral biomarkers, especially in point-of-care (POC) settings. These biosensors offer advantages such as high sensitivity, selectivity, ease of integration, and biocompatibility. This review provides an overview of the evolution and utilization of biosensors that rely on functional organic transistors, with a focus on electrolyte-gated organic field-effect transistors (EGOFETs) and organic electrochemical transistors (OECTs). First, the working principles and sensing mechanisms of various organic transistors are summarized. Then, recent progress and challenges in developing organic transistor-based biosensing platforms for detecting intraoral biomarkers are summarized, along with examples from representative studies. Last, prospects and opportunities for the advancement of organic transistor-based biosensors for oral health monitoring are discussed.