Molecularly imprinted CaCO3/polydopamine hybrid composite for selective protein recognition

Molecular imprinting has shown significant advances in the recognition and separation of small molecules. This technology has been proposed for different applications, including solid-phase extraction, stationary phases in HPLC, chemical sensing, drug-delivery systems, passive sampling, among others. However, imprinting of biological macromolecules with increased structural complexity is still challenging. In this work, CaCO 3 microparticles were synthesized using a precipitation method and employed as a novel support for the preparation of molecularly imprinted polymers (MIPs) towards a model protein (bovine serum albumin, BSA), through the polymerization of dopamine. Microparticles exhibited a rhombohedral morphology and a narrow size distribution (2.5 ± 0.4 µm). Reaction times showed to increase the polydopamine coating thickness, the MIP adsorption capacities, and the impression efficiency, reaching values of 5.1 nm, 50.2 ± 5.9 mg BSA/g sample, and 8.1 after 24 h, respectively. In addition, lower adsorption capacities were observed against proteins with similar physicochemical properties, such as ovalbumin (25.07 ± 2.5 mg/g) and casein (19.62 ± 7.01 mg/g). The adsorption kinetic assay indicated that MIPs present the highest BSA adsorption capacity after 1 h. In this regard, a methodology that offers a simple approach for the synthesis of materials designed for the specific recognition and separation of biological molecules is presented. The microparticles developed represent a potential use for protein separation in applications such as stationary phase in liquid chromatography. Graphical abstract