Molecular imprinting-based cryogel membranes for Pseudomonas aeruginosa separation

Molecularly imprinted polymers are highly functional materials used for the sensitive and selective separation of a wide range of compounds, from bacteria to heavy metals. Cryogels, a type of polymer that can be utilized in molecular imprinting, are considered strong candidates for various separation processes due to their high versatility and ease of synthesis. Pseudomonas aeruginosa is a common encapsulated, gram-negative, rod-shaped bacterium that can cause diseases in plants and animals, including humans. In this study, P. aeruginosa-imprinted cryogels based on 2-hydroxyethyl methacrylate and N-methacryloyl-L-histidine methyl ester (MAH)-Cu(II) coordination were synthesized, followed by detailed characterization of these materials using FTIR and SEM. Swelling tests were conducted to understand the nature of the material. Adsorption studies using UV-Vis spectroscopy demonstrated a concentration-dependent increase in absorbance, which plateaued at higher concentrations due to pore saturation. The equilibrium adsorption data were analyzed using the Langmuir and Freundlich isotherm models, with the results indicating preferential adsorption and heterogeneous behavior, respectively. The dimensionless separation factor from Langmuir’s isotherm confirmed favorable adsorption conditions. Reusability experiments showed that the cryogels could be reused efficiently, maintaining over 90% efficiency across ten adsorption-desorption cycles. MIP cryogel adsorbed more P. aeruginosa than the composition-matched NIP, and relative selectivity coefficients greater than 1 supported template-derived recognition. The maximum experimental adsorption capacity was 61.45 mg g−1, whereas the Langmuir-fitted maximum adsorption capacity was 52.79 mg g−1. These results demonstrate proof-of-concept selective recognition under controlled phosphate-buffered saline conditions; validation in mixed microbial populations and complex environmental or clinical matrices is required before practical application.