Antimicrobial pH-sensitive protein carrier based on modified xanthan gum

Abstract

Proteins have poor absorption efficiency through the gastrointestinal (GI) tract due to their physical and chemical instabilities and short half-life. The aim of the present study was to encapsulate bovine serum albumin (BSA) protein in an efficient potentially biodegradable pH-sensitive carrier based on crosslinked xanthan gum-g-poly (N-vinyl imidazole) for delivery in the intestines. The structure of crosslinked grafts was characterized with different analysis techniques: FTIR, XRD, TGA and FE-SEM/EDX. BSA uptake and release from loaded grafts were performed in two different pH media, acidic (pH 1.2) and slightly alkaline (pH 7.4) solutions, imitating the simulated gastric and intestinal pH, respectively, within various time intervals at body temperature (37 °C). The results showed that the swelling rate and the accumulative BSA release % were faster in pH 7.4 medium than in pH 1.2 medium. The BSA release results revealed that BSA release mechanism in both media followed non-Fickian release. The structural integrity of released BSA was elucidated with SDS-PAGE analysis and the obtained data confirmed that BSA was released without any deformation in its structure. Cytotoxicity of crosslinked grafts was studied against normal cell line by neutral red uptake assay test and the obtained results showed that the prepared grafted carriers possesses good biocompatibility and considered as safe carriers for protein delivery. In addition, investigation of their antimicrobial activities against Aspergillus niger and Staphylococcus aureus confirmed that they can be used as antimicrobial protein carriers to transfer the proteins through GI tract.