Multiple stimuli-switchable electrocatalysis and logic gates of L-cysteine based on P(DEA-co-VPBA) hydrogel films

In this work, poly(N',N-diethylacrylamide-co-4-vinylphenylboronic acid) (P(DEA-co-VPBA)) hydrogel films were successfully assembled on the pyrolytic graphite (PG) electrode by a simple radical polymerization. Reversible thermal, glucose and pH-triggered electrochemical reactions were obtained in the presence of 1,1'-ferrocene dicarboxylic acid (FDA) with electro-redox properties. The thermal response performances of the thin-film electrode were attributed to the PDEA component, the sensitive behaviors of glucose were ascribed to the VPBA component, and the sensitive behaviors of pH were affected by PDEA and VPBA. The electrocatalytic oxidation of L-cysteine by FDA on the hydrogel film electrodes significantly enhanced the difference between the on and off states of the multi-response cyclic voltammetry (CV) signals. This smart polymer hydrogel film electrode with amplified signals could be further used to realize a 4-input/9-output binary logic circuit, which was constructed with temperature, glucose, pH, and cysteine as inputs and different levels of Ipa and Ipc responses as outputs. Furthermore, a 2-to-4 decoder, a 4-to-2 encoder, and a 4-input keypad lock were built on the same platform. This polymer electrocatalysis system provides a novel idea for constructing complex biological computing systems.

Automated summary

Poly(N',N-diethylacrylamide-co-4-vinylphenylboronic acid) (P(DEA-co-VPBA)) hydrogel films were successfully assembled on pyrolytic graphite (PG) electrode by radical polymerization, exhibiting reversible thermal, glucose and pH-triggered electrochemical reactions. The thermal response was attributed to PDEA, glucose sensitivity to VPBA, and pH sensitivity to both PDEA and VPBA. The hydrogel film electrodes showed enhanced multi-response cyclic voltammetry (CV) signals through the electrocatalytic oxidation of L-cysteine by FDA, enabling the construction of a 4-input/9-output binary logic circuit and other complex biological computing systems.