Nano-Bio-Electronic Films as Functional Materials for Analytical Micro-Systems

Hadar Ben-Yoav, Biomedical Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel

Electrochemical Lab-on-a-Chip (LOC) biosensing devices are translational and mobile analytical micro-systems that provide numerous advantages in clinical diagnostics, bringing bench top methods to the point-of-care. However, these micro-systems suffer from limited biosensing performance due to miniaturization challenges such as low signal-to-noise ratio that is mainly governed by the small surface area of the sensing micro-electrode. Designing new electronic surfaces that selectively amplify the electrochemical currents generated by analytes, and can be easily integrated with conventional micro- and nano-fabrication techniques will improve the sensitivity and limit-of-detection of these devices. In this work, we will discuss the use of a stimuli-responsive biopolymer chitosan for a controlled biofabrication scheme with a high spatiotemporal resolution that enables functional and sensitive nanobioelectronic surfaces in microfabricated LOC devices. For example, we will demonstrate the utilization of nanometers-size films of chitosan modified with redox-active catechol moieties resulting in a redox-cycling system for electrochemical signal amplification. The redox-cycling system is used to amplify the electrochemical signal of a redox-active medication clozapine (CLZ) through a continuous cycle of CLZ oxidation followed by catechol reduction of CLZ. We will also present the use of chitosan to encapsulate carbon nanotubes and the ability of the resulted electrocatalytic bio-composite to amplify the electrochemical signal generated by CLZ. Biofabrication of nanometers-size films with unique electronic characteristics for seamless integration in biosensing micro-systems will enable rapid and low sample volume analysis of markers in biofluids (such as blood) and will hopefully improve personalized health monitoring.