Photo-Enhanced Chemo-Transistor Platform for Ultrasensitive Assay of Small Molecules

Abstract

Compared with traditional assay techniques, fieldeffect transistors (FETs) have advantages such as fast response, high sensitivity, being label-free, and point-of-care detection, while lacking generality to detect a wide range of small molecules since most of them are electrically neutral with a weak doping effect. Here, we demonstrate a photo-enhanced chemo-transistor platform based on a synergistic photo-chemical gating effect in order to overcome the aforementioned limitation. Under light irradiation, accumulated photoelectrons generated from covalent organic frameworks offer a photo-gating modulation, amplifying the response to small molecule adsorption including methylglyoxal, p-nitroaniline, nitrobenzene, aniline, and glyoxal when measuring the photocurrent. We perform testing in buffer, artificial urine, sweat, saliva, and diabetic mouse serum. The limit of detection is down to 10 −19 M methylglyoxal, about 5 orders of magnitude lower than existing assay technologies. This work develops a photoenhanced FET platform to detect small molecules or other neutral species with enhanced sensitivity for applications in fields such as biochemical research, health monitoring, and disease diagnosis.

Chemical Sensors Based on Covalent Organic Frameworks

“…Wang et al utilized a supercritical solvent-thermal method to grow a photoactive pyrene-functionalized COF (COF TP-py ) layer on GFET, which can effectively detect various small molecules (Figure 3b). [69] The pyrene groups on COF TP-py could absorb energy from incident light and generate abundant holeelectron pairs. Under the driving force of the built-in electric field, the photo-generated electrons were captured at the interface energy barrier in COF TP-py , while the photo-generated holes entered the graphene.…”