A zinc selective oxytocin based biosensor
E. Mervinetsky, I. Alshanski, K. K. Tadi, M. Hurevich, S. Yitzchaik, A. Dianat, J. Buchwald, R. Gutierrez, G. Cuniberti, M. Hurevich, and S. Yitzchaik
J. Mater. Chem. B 8 1 (2020)
Oxytocin is a peptide hormone with high affinity to both Zn2+ and Cu2+ ions compared to other metal ions. This affinity makes oxytocin an attractive recognition layer for monitoring the levels of these essential ions in biofluids. Native oxytocin cannot differentiate between Cu2+ and Zn2+ ions and hence it is not useful for sensing Zn2+ in the presence of Cu2+. We elucidated the effect of the terminal amine group of oxytocin on the affinity toward Cu2+ using theoretical calculations. We designed a new Zn2+ selective oxytocin-based biosensor that utilizes the terminal amine for surface anchoring, also preventing the response to Cu2+. The biosensor shows exceptional selectivity and very high sensitivity to Zn2+ in impedimetric biosensing. This study shows for the first time an oxytocin derived sensor that can be used directly for sensing Zn2+ in the presence of Cu2+.