We report the rational engineering of a two-α-helix protein via site-directed mutagenesis, wherein histidine residues at the native catalytic active site were substituted with cysteines and tyrosine residues were introduced in close proximity to these cysteine residues. This modification enabled the site-directed reduction and nucleation of free gold ions into size-tunable gold nanoclusters (AuNCs) exhibiting red, green, and blue photoluminescence upon ultraviolet excitation. Furthermore, by modulating the solution pH, we successfully fabricated nanofibers via the co-assembly of the protein and AuNCs. Comprehensive structural characterization confirmed the architecture of these biohybrid materials. Protein-AuNCs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), exhibiting peroxidase-like activity under specific conditions. Furthermore, this peroxidase-like activity was successfully applied to the colorimetric detection of glutathione with a linear response in the concentration range of 100–300 μM.
Yaoyu Liang, Jingsong Ma, Lei Shang et al.· ACS Applied Nano Materials· 0 citations
Diabetic chronic wounds remain a major clinical challenge due to persistent infection, excessive inflammation, and impaired tissue regeneration. Herein, we report a multifunctional peptide-based antibacterial hydrogel (PAHG) for treating infected wounds, constructed through the incorporation of Cys-Arg-NH2 (CR)-Ag nanoassemblies into a bioactive matrix. In this design, the CR dipeptide enables in situ reduction and stable coordination of silver ions, yielding CR-Ag nanoassemblies with controlled silver release and enhanced biocompatibility. Co-assembly of this antibacterial component with chitosan, gelatin, collagen, and epidermal growth factor (EGF) affords a three-dimensional hydrogel network that provides a moist wound microenvironment, structural support, and sustained release of pro-regenerative cues. The resulting PAHG system exhibits excellent antibacterial activity against Escherichia coli and methicillin-resistant Staphylococcus aureus, with inhibition efficiencies exceeding 80%, while maintaining high cytocompatibility with human skin fibroblasts (∼150% viability). In a diabetic infected wound model, PAHG significantly accelerates wound healing, achieving nearly complete closure within 12 days, accompanied by enhanced collagen deposition and no noticeable histopathological abnormalities in major organs. By integrating molecularly engineered antibacterial nanoassemblies with rationally designed multicomponent hydrogels, this work provides a promising strategy for the development of bio-based antimicrobial materials and chronic wound dressings.
Heng Ge, Wen Yuan, Yulin Sun et al.· Journal of materials chemist...· 0 citations
