Engineering organic electrochemical transistor (OECT) to be sensitive cell-based biosensor through tuning of channel area

Abstract

The barrier integrity of epithelial tissue is crucial to many physiological functions in multicellular organisms. Hence, several scientific techniques, such as epithelial voltohmmeter (EVOM) and electric cell-substrate impedance sensing (ECIS), were developed to assess barrier function for in vitro assays. Organic electrochemical transistor (OECT), in particular, outperforms many biosensors because of its multiple advantages such as high transconductance, mixed ionic-electronic conductivity and high biocompatibility. Despite its extensive application in cell impedance sensing, little was reported on how its geometrical dimensions would affect the device performance and quality of cell-based measurement. In this work, OECTs in different dimensions were fabricated and characterized. Specifically investigated were their time and frequency responses towards the presence of epithelial cells (i.e. tightly packed colorectal adenocarcinoma cell line caco-2 and a novel leaky nasopharyngeal carcinoma cell line NPC43). Results show that the sensitivity of cell-based measurement is closely related to the impedance of the whole cell-OECT system. The performance of cell-based sensor would be affected by the tightness of target cell and can be tuned by controlling the active area of OECT.