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The pH value in the wound milieu plays a key role in cellular processes and cell cycle processes involved in the process of wound healing. Here, a microfluidic assembly technique is employed to fabricate micro-gel ensembles that can precisely tune the pH value of wound surface and accelerate wound healing. The micro-gel ensembles consist of poly (hydroxypropyl acrylate-co-acrylic acid)-magnesium ions (poly-(HPA-co-AA)-Mg 2+ ) gel and carboxymethyl chitosan (CMCS) gel, which can release and absorb hydrogen ion (H + ) separately at different stages of healing in response to the evolution of wound microenvironment. By regulating the wound pH to affect the proliferation and migration of cell on the wound and the activity of various biological factors in the wound, the physiological processes are greatly facilitated which results in much accelerated healing of chronic wound. This work presents an effective strategy in designing wound healing materials with vast potentials for chronic wound management., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The abuse of antibiotics leading to bacterial resistance has emerged as a significant impediment to wound healing. Consequently, this study developed antibacterial and anti-inflammatory bi-functional carbon dots (AAB-CDs) as the primary active material for the preparation of hydrogel wound dressings, aiming to promote wound healing. The synthesized AAB-CDs exhibited ultra-small size (2.3 nm), abundant surface functional groups, high Zeta potential (30.9 mV), and excellent biocompatibility. The positively charged AAB-CDs with outstanding antibacterial properties, mitigating the risk of bacterial resistance, while the abundant surface functional groups imparted stable antioxidant performance for sustained wound anti-inflammatory effects. Moreover, in vitro experiments demonstrated that the hydrogel dressings exhibited remarkable antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and significantly promoted the proliferation of L929 fibroblasts. In vivo experiments further substantiated the feasibility of the hydrogel dressings in promoting wound healing and histological analysis revealed the biological mechanisms underlying the promotion of wound healing. In conclusion, AAB-CDs with robust antibacterial and anti-inflammatory properties hold tremendous potential for promoting wound healing, providing practical insights for the biological application of CDs. Robust antibacterial and anti-inflammatory bi-functional carbon dots (AAB-CDs) are designed with ultra-small size (2.3 nm), high Zeta potential (30.9 mV) and remarkable antioxidant ability. Then AAB-CDs are doped in biocompatible hydrogel dressing fabricated with the monomers of N-vinyl-2-pyrrolidinone (NVP) and N-(hydroxymethyl) acrylamide (NMA). The resultant hydrogel dressing exhibits continuous AAB-CDs release capacity for long-acting treatment that promotes wound healing. [Display omitted] • Antibacterial and anti-inflammatory bi-functional carbon dots were prepared. • Hydrogel dressing was used to promote wound healing by continuously releasing CDs. • In vitro and in vivo experiments were performed to confirm the treatment effect. [ABSTRACT FROM AUTHOR]

Self-pumping wound scaffolds designed for directional biofluid transport are extensively investigated. They efficiently extract excessive biofluids from wounds, while maintaining an optimally humid wound environment, thus facilitating rapid wound healing. However, the existing designed scaffolds are insufficiently focused on stimulating the hydrophobic layer at the wound site, thereby exacerbating inflammation and impeding the wound healing process. Herein, we engineered and fabricated a hydrophilic-hydrophobic-hydrophilic sandwich-structured hydrogel-Janus nanofiber scaffold (NFS) employing a Layer-by-Layer (LbL) method. This scaffold comprises a hydrophilic carboxymethyl chitosan/silver (CMCS-Ag) hydrogel component in conjunction with a poly(caprolactone)/poly(caprolactone)-poly(citric acid)- co - ε -polylysine (PCL/PCL-PCE) Janus NFS. It is noteworthy that the hydrogel-Janus nanofiber scaffold not only demonstrates outstanding water absorption (202.2 %) and unidirectional biofluid transport capability but also possesses high breathability (308.663 m3/m2 h kPa), appropriate pore size (6.7–7.5 μm), excellent tensile performance (270 ± 10 %), and superior mechanical strength (26.36 ± 1.77 MPa). Moreover, in vitro experimentation has convincingly demonstrated the impeccable biocompatibility of hydrogel-Janus NFS. The inherent dual-antibacterial properties in CMCS-Ag and PCE significantly augment fibroblast proliferation and migration. In vivo studies further underscore its capability to expedite wound healing by absorption and expulsion of wound exudates, thereby fostering collagen deposition and vascularization. As such, this work potentially provides fresh insights into the design and fabrication of multifunctional biomimetic scaffolds, holding immense potential in the medical field for efficient wound healing. [Display omitted] [ABSTRACT FROM AUTHOR]