Polymer structures on sensor surfaces are known to have reproducibility and reusability issues caused by hydrodynamic shifts, minor changes in surface coverage, charging of the surface, and steric restructuring of the polymer surfaces. Within our laboratory, we primarily use elastin-like polymers and hydrophobic-self-assembled-monolayer:cyclodextrin complexes as functional polymers on sensor surfaces. Often, with these polymers, the same methodology does not lead to the same surface modification due to small minor surface changes including physiosorbed surface content or steric hinderances. Therefore, attention and strategy are needed to ensure a reproducible sensor surface. Further, we use electrochemical impedance spectroscopy, a highly sensitive but difficult to reproduce strategy in biosensors because small surface changes can result in large changes in the recorded signal. We will discuss our methodological approaches to achieve reproducible and reusable sensor using polymer surfaces with electrochemical impedance spectroscopy. Our group cares about reusability as a long-term sensor strategy towards measuring bioanalyte content ex vivo
in biofluid samples. We will discuss both positive and negative approaches to generate the same results over multiple sensors, and the ability to regenerate a sensor for reuse. Further, we will talk about voltage dependency of the surface and ability to reproducibly detect nanomolar chemical changes.
The author would like to acknowledge the support from NSF EAGER (CBET 1638896) and NIH CIBBR (P20GM113131). This contribution would not be possible without the endless support of the undergraduate students, graduate students, post doctorates, and collaborators of the Surface Enhanced Electrochemical Diagnostic Sensors Laboratory.