Utilizing organic electrochemical transistors for electrical characterization of conformational changes in charged peptides

Engineered bio-surfaces made of stimuli-responsive materials have the potential to shed new light on how cells respond to their surroundings and regulate various cellular activities in real time. Organic bioelectronics, such as electrically active organic surfaces, have enabled rapid, simple, and spatiotemporal bio-molecular switching, consequently facilitating interactions between bio-functionalized electrodes and biological systems, such as cells or tissues. Here, we attempted to imitate the notch signaling system by using charged peptides with the Notch-ligand sequence that are effectively controlled by electro-responsive surfaces. Although we have shown that optical techniques can be used to view peptide conformational changes, we describe the development of an electrical tool that will allow in-situ monitoring of cell activation and provide input for ongoing research. Organic electrochemical transistors (OECT) are being investigated for various applications, including brain interfaces, chemical and biological sensors, printed circuits, and neuromorphic devices. We take advantage of OECTs because of their mixed ion-to-electron converting properties; these devices can efficiently use ion injection from an electrolyte to alter the electronic conductivity of the channel's organic semiconductor. By applying an electrical potential to a functionalized gate electrode, the dipole moment of the charged peptides will change the polarization of the gate electrode, resulting in a change in the source-drain current. Conformational changes in charged peptides generate a significant signal in these systems, which can be detected using organic electrochemical transistors, as depicted in the figure below. This cell-friendly bioelectronic device can electrically detect the conformational changes of peptides. Finally, we studied various charge peptides and employed additional characterization techniques to confirm the electronic detection platform's findings.