(2md) Conjugated polymers based bioelectronic sensors for living-nonliving interfaces

Organic electrochemical transistors (OECTs) are electronic interfacing devices well known for miniaturized, fast, amplified, wearable, biocompatible, stretchable and robust devices for several applications such as bio-sensing, healthcare monitoring, amplifiers, logic gates, neural interfaces, human stimulating tools, neuromorphic computing and many more. Although numerous applications it has, is still has lot of room for further development. For the same, I have developed (a) OECTs based microbial sensors for wastewater chemical sensing at Rice university, wearable skin mountable fully soft robust OECTs for (b) electrophysiological signal acquisition and (c) neuromorphic computing at UNIST, South Korea. Electroactive microbes such as Shewanella Oneidensis are capable of producing electrical current using a process called extracellular electron transfer (EET). It is also possible to synthetically engineer the EET pathway to achieve EET in microorganisms that are not naturally exoelectrogenic (e.g., Escherichia coli) and to couple the EET pathway to the presence of specific chemical or molecular targets. This provides an opportunity to develop living microbial sensors that produce electronic signals in response to environmental cues. However, we lack a miniaturized, portable architecture capable of interfacing with electro-active microbes and reporting on EET. Here, we report the integration of electro-active microbes with OECTs as a miniaturized, sensitive, and fast sensors. This project is funded by Army research office MURI program, US gov. Fully soft, skin mountable OECTs on-skin electronics. The key part of this research is to develop skin mountable, stretchable electronic interface with all soft components of the device. The electrodes were fabricated by embedding silver nanowires in a polymer for instance PDMS, SEBS, SBS. The channel is fabricated using stretchable conjugated polymer PEDOT: PSS with a plasticizer PEG and crosslinker DVS. The device shows enhanced electric as well as mechanical properties than reported devices earlier in this field. The OECT along with a variable resistor as amplifier has been demonstrated to monitor the amplified physiological signals.

Keywords: Chemical Engineering, Polymers, Conducting polymers, Conjugated polymers, Bioelectronics, wearable devices

Teaching interests:

I have experience of teaching to chemical engineering undergraduate students. During my faculty position at National Institute of Technology AndhraPradesh, India, I have taught ‘Elements of transport phenomena’ and ‘Renewable energy sources’ courses to third year undergraduate courses. During the semester, for both the courses were taught to all types of learners using active learning strategies. While teaching transport phenomena, the objective of the course was introduced with actual examples of chemical industry outline such as combined fluid, mass and heat flow in non-isothermal reactions in tubular reactors. During interactive sessions, students were motivated to find such examples in day today life and model set of equations. However, while teaching other course on renewable energy sources, students were encouraged to prepare presentations on their own possible undergraduate projects for energy conversion. During my Ph.D. at Indian Institute of Technology Madras India, I have experience of teaching as well as research assistance in the institute. I have assisted to the course on ‘Introduction to research’, which is an institute level introductory course for graduate research-based masters as well as doctoral courses. I have also assisted to my advisor Prof. Susy Varughese for the course titled, ‘Polymers for devices’, in which I have assisted students with course projects on electronically conducting polymers. I have also assisted professors with laboratories courses viz. heat and mass transfer laboratory, thermodynamics laboratory. Prior to my Ph.D., I was working as assistant professor in an undergraduate engineering institute for more than two years, where I have taught in department of chemical engineering. I have taught Fuel cell technology for consecutive three semesters, Process dynamics and control and membrane separation technology.

Selected Publications:

1. Haechan Park, Sehyun kim, Juyeong Lee, Inwoo Lee, Sujitkumar Bontapalle, Younghoon Na, Kyoseung Sim; Recyclable organic flexible electronics with an eco-friendly and economical approach to sustainable wearable technologies, Accepted at Nature Electronics.

2. 2. Sujitkumar Bontapalle, Myeonghyeon Na, Haechan Park, Kyoseung Sim; Fully soft organic electrochemical transistor enabling direct skin mountable electrophysiological signal amplification, Chemical Communication, 58 (9), 1298, 2022 (Artwork is Front cover of volume 58, Issue 9, Jan 2022 ).

3. Andreas Opitz, Dominique Lungwitz, Raphael Schlesinger, Sujitkumar Bontapalle, Susy Varughese, Keli Fabiana Seidel, Thomas Krüger, Jan Behrends, Seth R. Marder, and Norbert Koch; Polyethylenimine cathode interlayer; influence of solvent on functionality and single-step formation from polymer blend solution, Proc. SPIE 11809, Organic, Hybrid, and Perovskite Photovoltaics XXII, 118090Q, 2021.

4. Sujitkumar Bontapalle, Andreas Opitz, Raphael Schlesinger, Seth Marder, Susy Varughese, Norbert Koch; Electrode work function reduction by polyethylenimine interlayers: Choice of solvent and residual solvent removal for superior functionality, Advanced Materials Interfaces, 7 (11), art. No. 2000291, 2020.

5. Sujitkumar Bontapalle, Susy Varughese; Understanding the mechanism of ageing and a method to improve the ageing resistance of conducting PEDOT:PSS films, Polymer Degradation and Stability, 171, art no. 109025, 2020.

6. Sujitkumar Bontapalle, Upendra Natarajan; Thermodynamic free energy behavior of diblock copolymer chains confined between planar surfaces having end-tethered flexible polymer molecules, Journal of Macromolecular Science: B (Physics Ed.), Vol. 51, Issue 7, Pg. no. 1282-1302, 2012.

7. Sujitkumar Bontapalle, Upendra Natarajan; Molecular thermodynamics of polymer chains confined between planar surfaces bearing end-tethered flexible molecules, Journal of Macromolecular Science: B (Physics Ed.), Vol. 51, Issue 1, Pg no. 163-184, 2012.