Molecularly imprinted nanoparticles (MIP-NPs) are recognition elements obtained upon the polymerization of functional monomers around the target template, that, once removed, reveals selective binding sites in the polymeric matrix enabling the target binding with high specificity. Due to their small size, the binding sites are mostly located at the surface of the polymer, which definitely improves the binding kinetics. Solid-phase synthesis with an excess of the functional monomer NIPAm (N-isopropylacrylamide) confers a thermoresponsive character to the polymers, thus acquiring a solvated gel-like nanometer-sized feature, while the use of a protein epitope avoids the challenging issues related to the whole protein imprinting. Once produced, epitope-imprinted nanogels (MIP-NGs) can be anchored onto the surface of electrochemical transducers, thus leading to the development of selective electrochemical sensors. In this work, MIP-NGs for the cardiac cell damage biomarker cardiac troponin T (cTnT) were anchored onto screen-printed carbon electrodes, enabling a linear impedimetric response in the concentration range 0.01–0.3 ng/mL with a LOD of 0.004 ng/mL. The sensor showed a negligible response towards interfering proteins and a reliable detection of the target protein in undiluted serum. To the best of our knowledge, for the first time an electrochemical sensor based on molecularly imprinted nanogels produced by solid-phase synthesis in aqueous environment with a protein epitope as template was developed for the detection of cTnT. The sensor featured analytical performances comparable to currently available immunoassays, thus showing a striking potential application as alternative tool for myocardial damage biomarker detection. • MIP-NGs for cTnT are synthesized by solid-phase synthesis and epitope imprinting. • A MIP-NGs-based electrochemical sensor is assembled by electrografting. • The sensor enables the rapid detection of the epitope and whole protein. • The selectivity test shows a negligible response towards interfering proteins. • The sensor is successfully applied for protein detection in undiluted serum.
Gagliani et al. (Sun,) studied this question.