Fabrication of Micro Optical Ring Electrodes for Scanning Photoelectrochemical Microscopy Applications

Abstract

Micro-Optical-Ring electrodes (MOREs) have shown their usefulness in nonbiological applications in the past, but their application to biological samples for diagnostic purposes has yet to be explored. Herein, a simple and cost effective fabrication method of MOREs with a defined geometry is presented. These microelectrodes were characterized by electrochemistry, numerical modeling and Scanning Electron Microscopy (SEM). The integration of MOREs into scanning probe techniques, such as Scanning Electrochemical/Photoelectrochemical Microscopy (SECM/SPECM) enables the sensitive detection and quantification of cell metabolites at the micro- and nanoscopic level. The applicability of the fabricated MOREs was tested by monitoring oxygen production in the biological model systems of Chlorella kessleri and Eremosphaera viridis. A variation in oxygen production levels by the algae was observed in the presence and absence of light, emitted through the MORE-integrated optical fiber. This proof-of-concept study demonstrates the applicability of MOREs to biological systems.