On/off-switchable electrochemical folic acid sensor based on molecularly imprinted polymer electrode

•Folic acid sensor based on temperature sensitive polymer is reported.•The folic acid-imprinted electrode was obtained by electropolymerisation of functional monomers.•The analytical performance of the sensor was evaluated by electrochemical methods.•A highly specific electrochemical molecular recognition was established on electrode with switching ability.

The combination of smart polymers with molecular imprinting offers a powerful tool to design more effective sensors and medical devices. In this study, a temperature sensitive amine-terminated poly(N-isopropylacrylamide) block with (N,N'-methylenebisacrylamide) cross-linker along with o-phenylenediamine was electropolymerised on a gold electrode in the presence of folic acid (FA) as template to produce an on/off-switchable molecularly imprinted polymer (MIP) affinity sensor for folic acid. Differential pulse voltammetry and cyclic voltammetry were used to characterise the FA-imprinted layer. Incubation of the MIP-modified electrode with FA resulted in a suppression of the ferro/ferricyanide redox process. The highest sensitivity of this temperature gated on/off-switchable folic acid sensor was achieved at 22 °C. Such switchable affinity materials offer considerable potential for the design of highly selective and controllable biosensors and immunoassays.