Investigations of Peptide-Based Biocompatible Injectable Shape-Memory Hydrogels: Differential Biological Effects on Bacterial and Human Blood Cells

Here, we report the self-assembly of Amoc (9-anthracenemethoxycarbonyl)-capped dipeptides, which self-assemble to form injectable, self-healable, and shape-memory hydrogels with inherent antibacterial properties. Amoc-capped dipeptides self-assemble to form nanofibrillar networks, which are established by several spectroscopic and microscopic techniques. The inherent antibacterial properties of hydrogels are evaluated using two Gram-positive Staphylococcus aureus, Bacillus subtilis and three Gram-negative Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi bacteria. These hydrogels exhibit potent antibacterial efficacy against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentrations (MIC₅₀) for the hydrogels on Gram-positive bacteria are in the range of 10-200 μM hydrogelator concentrations. The biocompatibility and cytotoxicity of the hydrogels are evaluated using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), hemolysis, and lipid peroxidation (LPO) assay on human blood cells. The hydrogels are hemocompatible and they decrease LPO values on human red blood cells probably via increased cellular stability against oxidative stress. Furthermore, MTT data show that the hydrogels are biocompatible and promote cell viability and proliferation on cultured human white blood cells. Taken together, these results may suggest that our designed injectable hydrogels could be useful to prevent localized bacterial infections.