A novel antibacterial hydrogel containing aminophylline as a versatile platform for neural differentiation of hWJMSCs through the CREB pathway

This study aims to develop a novel antibacterial hydrogel scaffold composed of gelatin (Gel), amniotic membrane extract (AME), and aminophylline (AMP) for neural regeneration. We investigate its ability to sustain AMP release, inhibit bacterial growth, and promote neural differentiation of human Wharton's jelly mesenchymal stem cells (hWJMSCs) via the CREB pathway, addressing unmet needs in neural tissue engineering. The composite hydrogels were synthesized and characterized using various methods and techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), porosity, contact angle, water uptake, thermogravimetric analysis (TGA), biodegradation, tensile strength, drug release, and antibacterial activity. Biocompatibility tests (MTT assay, AO/EB staining) confirmed > 95% viability of hWJMSCs over six days and their differentiation to the neural cells was analyzed through immunocytochemistry (ICC) staining and real-time reverse transcription-polymerase chain reaction (RT-PCR) at different time points. The results demonstrate the successful synthesis of porous hydrogels with desirable properties, including hydrophilicity, thermal stability, biodegradability, and mechanical strength. The hydrogels support the sustained release of AMP (53.18% over 336 h) and exhibit antibacterial activity against Pseudomonas aeruginosa (90.52 ± 0.26%) and Staphylococcus aureus (93.06 ± 0.34%) due to the presence of penicillin and streptomycin (P-S) antibiotics. The biocompatibility results show that the hydrogels do not have a cytotoxic effect on the viability of human WJMSCs. The neural differentiation of human WJMSCs seeded on surface hydrogels was confirmed by evaluating specific neural markers at both protein and gene levels. In conclusion, the new antibacterial gel-based hydrogel can support the release of AMP and after further evaluation, can be introduced as a new candidate for neural repair applications.