Next-generation antibacterial cryogels: Berberine-infused smart membranes with molecular docking-guided targeting of MRSA and MDR E. coli

Abstract

Multidrug-resistant (MDR) bacteria have become a significant global concern in recent years, necessitating the development of innovative strategies to combat these pathogens. Berberine, a bioactive alkaloid found in Berberis vulgaris, Berberis aquifolium, Coptis chinensis, Coptis japonica, and Hydrastis canadensis, exhibits a broad spectrum of biological activities, including antibacterial effects. However, its low aqueous solubility limits its bioavailability, restricting its therapeutic potential. Poly(2-hydroxyethyl methacrylate) (pHEMA)-based cryogel membranes, known for their biocompatibility and ease of synthesis, have been widely utilized in biomedical applications, particularly in wound healing. In this study, berberine was successfully incorporated into pHEMA cryogel membranes and characterized using FT-IR spectroscopy. Biocompatibility assessments were conducted using L929 fibroblast cells, and MTT assay results confirmed that cell viability remained above 88 %, indicating good biocompatibility. The antibacterial properties of the prepared membranes against MDR E. coli and MRSA were evaluated using the disk diffusion and time-kill methods. According to the time-kill assay, high-dose berberine-loaded cryogel membranes (BM2) exhibited inhibition rates of 87.2 % against MRSA and 96.8 % against MDR E. coli. The antibacterial and antibiofilm effects of the membranes were further validated by SEM imaging, which revealed that berberine effectively disrupted bacterial biofilms. To gain insight into the molecular mechanisms underlying antibacterial activity, molecular docking studies were performed on key bacterial proteins involved in essential physiological processes, including the OmpA transmembrane domain (PDB ID: 1BXW), E. coli DNA gyrase B (PDB IDs: 4WUB, 6KZX, 6KZV), E. coli hydrogenase (PDB ID: 5LMM), penicillin-binding protein 3 (PBP3; PDB ID: 3VSL), and PBP2a from MRSA (PDB IDs: 1MWT, 4CJN, 5M18, 6Q9N). The strongest interaction was observed between berberine and 6KZX, with a docking score of −7.898 kcal/mol, whereas the weakest interaction was noted with 4CJN, with a docking score of −3.743 kcal/mol. These findings highlight the potential of berberine-loaded pHEMA cryogel membranes as a promising antibacterial platform for combating MDR bacterial infections, particularly for wound healing applications.