Analysis of Label-Free Single-Molecule Biosensors based on Gate-Biofunctionalized Organic Transistors

A label-free single-molecule detection platform based on biofunctionalized organic transistors has been recently proposed. In contrast to state-of-art approaches based on nano-transducers, the aforementioned single-molecule transistor (SiMoT) sensing technology is based on millimeter-sized transistors where the gate is bio-functionalized with about a trillion of antibodies. In this work we provide a detailed investigation of SiMoT biosensors by studying and quantifying the device parameters affected by the biorecognition event. The study combines both measurements and theoretical analyses, showing that a single protein detection taking place at nanometer scale affects a millimeter scale area of the biofunctionalized gate electrode. The dimension of the bioprobe domains affected by the binding is calculated as a function of the nominal protein concentration in the analyte solution. These results provide important insight into the SiMoT biosensor technology, which can guide the development of multi-modal SiMoT detection and integrated SiMoT biosensors arrays.