Fabrication of Nanotips for Microelectrode Array Sensors Using Meniscus Etching

In this paper, a substantially improved method of fabricating glass microelectrode array sensors for in situ measurements is reported. Meniscus etching with HF-based etchant was used to fabricate nanotips in a repeatable and consistent manner. The meniscus etching process was fully characterized for the etching of glass probe arrays, both numerically and experimentally. Overall, this fabrication method provides a simple, repeatable, high yield, low cost approach to fabricating sharp (<200 nm) microelectrodes with tip angles from 4deg to 49deg. To demonstrate superior robustness of the improved microelectrodes, probes were successfully penetrated into agarose biofilm surrogate more than 25 times without any damage or degradation to perform reduction oxidation potential (ORP) measurements.