Surface-localized thermoresponsive molecularly imprinted polymer for gentamicin recognition and aqueous regeneration

Gentamicin is a widely used aminoglycoside antibiotic whose selective extraction from aqueous matrices remains challenging because of its high polarity and the presence of structurally diverse coexisting compounds. Molecularly imprinted polymers (MIPs) offer selective recognition of target molecules; however, conventional bulk-imprinted materials may suffer from limited accessibility of recognition sites and relatively long mass-transfer pathways. In this study, a thermoresponsive core-shell MIP was developed for the selective extraction and temperature-controlled regeneration of gentamicin. A PVC-based core was functionalized with a surface-associated molecularly imprinted polymer phase containing poly(N-isopropylacrylamide), providing temperature-responsive behavior that enables aqueous regeneration of the sorbent. The performance of the core-shell MIP was compared with that of the corresponding non-imprinted material and evaluated in static sorption and solid-phase extraction experiments. The MIP exhibited a higher gentamicin sorption capacity than the non-imprinted material, reaching 3.90 mg g^-1 compared with 2.80 mg g^-1, corresponding to an imprinting factor of 1.4. Temperature-dependent desorption enabled regeneration of the sorbent using cold water, with regeneration efficiencies of 94-100% during the initial cycles. The material also demonstrated preferential recognition of gentamicin in the presence of other antibiotics. The surface-localized architecture distinguishes the present material from the previously reported bulk-imprinted thermoresponsive gentamicin sorbent. The developed approach demonstrates the potential of combining surface molecular imprinting with thermoresponsive polymer functionality for selective solid-phase extraction and aqueous regeneration of gentamicin.