Electro-responsive Molecularly Imprinted Polymers (E-MIPs) for Rapid Detection of Progesterone in Human Serum Samples

Rapid and reagent-free detection of progesterone (P4) is crucial in point-of-care (POC) measurement due to its important role in the human endocrine and central nervous system. Currently available technologies for P4 detection are often not rapid or require reagents, limiting their use in POC settings. In this work, a self-signaling electrochemical sensing platform for rapid detection of P4 is developed by using electroactive molecularly imprinted polymers (E-MIPs). E-MIPs possess the ability to transduce the molecular recognition event into a measurable electrochemical signal. The E-MIPs are prepared by bulk copolymerization of acrylic acid (AA) and ferrocenylmethyl methacrylate (FcMA) in the presence of P4 followed by its removal from the polymer matrix. By incorporation of ferrocene moieties, the MIP gains intrinsic electroactivity, enabling label-free and direct electrochemical detection of P4 levels. Electrochemical techniques, including cyclic voltammetry and electrochemical impedance spectroscopy, were employed to elucidate the electron transport reaction responsible for the MIP's intrinsic electroactivity. Additionally, the predetermined complementary binding sites confined to the small working area of the screen-printed carbon electrode (SPCE) within the E-MIP matrix facilitate rapid P4 binding, achieving completion within 120 s. The developed E-MIP sensing platform was used for the rapid detection of P4 levels in human serum samples. The short incubation times reported for the E-MIP sensing platform would be beneficial in minimizing the nonspecific binding in the real-world samples. We believe that the proposed E-MIP sensing platform can be applied to clinical samples for detecting fluctuations in P4 levels.