Preparation And Biological Properties Of Amino Acid-based Antibacterial Hydrogels

In recent years,the problem of the bacterial resistance is being more and more serious.Superbugs have received widespread attention due to their significant threats to human health.In this grim situation,looking for alternatives to traditional antibiotics is urgently required.Amino acid or peptide based supramolecular hydrogels have attracted more and more attention due to their cost effectiveness,high biocompatibility,high drug loading capacity and chemical diversity.In this paper,Fmoc-amino acids were used as the basic building blocks to prepare hydrogels with good antibacterial activity(1)Structure-Dependent Antibacterial Activity of Amino Acid-Based Supramolecular Hydrogels.Stable and transparent self-supporting hydrogels were fabricated by self-assembly of Fmoc-W,Fmoc-M,and Fmoc-Y.The antibacterial activity of the four types of Fmoc-amino acid hydrogel was in the following order:Fmoc-W hydrogel>Fmoc-F hydrogel>Fmoc-M hydrogel>Fmoc-Y hydrogel,which was combined with the results of the antibacterial tests.Furthermore,these hydrogels can destroy the cell walls and membranes of Gram-positive bacteria.TEM reveled that these hydrogels were composed of three-dimensional nanofiber network.However,more rigid and aligned nanofibers were observed for the Fmoc-W hydrogel.A stronger aggregation capability,as well as morphology with more rigid and aligned nanofibers,will lead to higher antibacterial activity of their hydrogels.Furthermore,their antibacterial activity may also be related to the molecular arrangements of Fmoc-amino acids in the hydrogels.(2)Amino acid/Berberine Directed Self-Assembly of AIE-active Hydrogels with Enhanced Photodynamic Antibacterial and Biofilm-disrupting Activity.A novel photodynamic antibacterial and biofilm-disrupting hydrogel with AIE features was fabricated.Because of the electrostatic interaction and π-π stacking,.BBR can self-assemble into hydrogel matrix,which endowed Fmoc-F/BBR hydrogel with AIE characteristics.Under white light irradiation of 60 min,Fmoc-F/BBR hydrogel could effectively inhibit 100%S.aureus and 79.1%E.coli,as well as eradicate 85.8%S.aureus and 59.3%E.coli biofilms.The hydrogel showed no obvious cytotoxicity and low hemolytic to mammal cells,even upon the irradiation of light.In addition,animal study showed that the Fmoc-F/BBR hydrogel have great therapeutic efficacy on the S.aureus infected wounds.