Branched polyethylenimine-assisted boronic acid functionalized magnetic nanoparticles for highly efficient capture of lincomycin and clindamycin

Abstract

As lincosamide antibiotics, lincomycin and clindamycin are widely used in the drug manufacturing industry for the health of human beings and animals. Thus, the quantitative detection of them in real samples is of great significance. Due to the presence of complex interfering components in actual samples, the separation and enrichment of lincomycin and clindamycin prior to analysis are key. Therefore, it is necessary to develop a non-complex, cost-effective enrichment method for them. A five- or six-membered boronic cyclic ester is formed through boronate affinity materials binding a cis-diol-containing compound in aqueous media, which is a reversible reaction. However, low binding capacity and affinity, and high binding pH of boronate affinity materials are key concerns. In this study, polyethylenimine-assisted 3-fluoro-4-formylphenylboronic acid functionalized magnetic nanoparticles were developed to capture efficiently cis-diol-containing lincomycin and clindamycin under neutral conditions. Thereinto, polyethylenimine (PEI) was applied as a scaffold to amplify the number of boronic acid moieties. And 3-fluoro-4-formylphenylboronic acid was used as an affinity ligand due to its excellent water solubility and low pK_a value toward lincomycin and clindamycin. The results indicated that the prepared branched boronic acid-functionalized MNPs provided high binding capacity and fast binding kinetics under neutral conditions. Furthermore, the obtained MNPs exhibited relatively high binding affinity (K_d ≈ 10⁻⁴ M) and low binding pH (pH ≥ 6.0).