Co-polymers of oligolactic acid and tetrasubstituted thiacalix[4]arenes as a new material for electrochemical sensor development

Abstract

© 2017New derivatives of oligolactic acid (OLA) have been obtained by cross-esterification with carboxylated thiacalix[4]arene derivatives in cone, paco and 1,3-alternate configurations. The products of the reaction characterized by NMR 1H, FTIR-ATR spectroscopy, MALDI-TOF mass spectroscopy and elemental analysis have been applied for surface modification of glassy carbon electrode (GCE). Electrochemical characterization with redox probes (ferricyanide ion and Methylene blue (MB)) showed predominant influence of electrostatic interactions influencing the flux of the charge carriers over the diffusion control. The role of a macrocycle moiety on the surface morphology and sensitivity toward measurement conditions has been established. The electrodes covered with new materials were applied as transducers in sensing specific DNA interactions and acetylcholinesterase (AChE) based hydrolysis of acetylthiocholine. This made it possible to distinguish factors affecting the DNA structure (MB intercalation, oxidative DNA damage, thermal denaturing) whereas immobilization of the AChE on the silver dendrites deposited in the inner volume of the polymers allowed recording the signal of thiocholine oxidation at extremely low working potential (0 mV vs. Ag/AgCl).