Probing the molecular basis for sulfonamides recognition in surface molecularly imprinted polymers using computational and experimental approaches

Abstract

The computer-aided design of surface molecularly imprinted polymers (SMIPs) of sulfadimethoxine (SDM) using methacrylic acid (MAA), 4-vinylpyridine (4-VP) or 4-aminostyrene (AS) as functional monomers was performed using Gaussian software, and the corresponding materials were innovatively prepared by surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA ATRP) using an Fe(0)/Cu(II) catalytic system. Sulfonamides were selected as template molecules because of their stable nuclear parent and regular side chain changes, which could help explore the molecular mechanism of imprinting and recognition from the perspective of structural differences. The imprinted systems were calculated using Gaussian software to obtain parameters related to intermolecular interactions. The morphology and physicochemical properties of SMIPs were determined by scanning electron microscope (SEM), oxygen bomb combustion-ion chromatography (OBC-IC) and thermogravimetric analyzer (TGA). The relevant adsorption mechanism was evaluated using the Langmuir–Freundlich (LF) isotherm. The adsorption capacities (Q) of the three SMIPs for nine other sulfonamides were evaluated by experiments, and the weak interaction energy between other sulfonamide molecules and the molecularly imprinted pores generated by SDM was simulated. Compared with the two other functional monomers, MAA demonstrated advantages in Q, pore uniformity, and imprinting factor. Weak interaction energies between the drug and functional monomer, as the main influencing factor, and steric hindrance as a secondary factor, influenced the Q, difficulty of template elution, and selective adsorption of the polymers for the nine other sulfonamides. Quantum chemical calculation data revealed that the number of hydrogen bonds generated, the participation of other weak interactions, and the charge of hydrogen bond donors had great influence on the weak interaction energy.