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Electrical stimulation can facilitate wound healing with high efficiency and limited side effects. However, current electrical stimulation devices have poor conformability with wounds due to their bulky nature and the rigidity of electrodes utilized. Here, a flexible electrical patch (ePatch) made with conductive hydrogel as electrodes to improve wound management was reported. The conductive hydrogel was synthesized using silver nanowire (AgNW) and methacrylated alginate (MAA), with the former chosen as the electrode material considering its antibacterial properties, and the latter used due to its clinical suitability in wound healing. The composition of the hydrogel was optimized to enable printing on medical-grade patches for personalized wound treatment. The ePatch was shown to promote re-epithelization, enhance angiogenesis, mediate immune response, and prevent infection development in the wound microenvironment. In vitro studies indicated an elevated secretion of growth factors with enhanced cell proliferation and migration ability in response to electrical stimulation. An in vivo study in the Sprague-Dawley rat model revealed a rapid wound closure within 7 days compared to 20 days of usual healing process in rodents., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Diabetic wound treatment faces significant challenges in clinical settings. Alternative treatment approaches are needed. Continuous bleeding, disordered inflammatory regulation, obstruction of cell proliferation, and disturbance of tissue remodeling are the main characteristics of diabetic wound healing. Hydrogels made of either naturally derived or synthetic materials can potentially be designed with a variety of functions for managing the healing process of chronic wounds. Here, a hemostatic and anti-inflammatory hydrogel patch is designed for promoting diabetic wound healing. The hydrogel patch is derived from dual-cross-linked methacryloyl-substituted Bletilla Striata polysaccharide (B) and gelatin (G) via ultraviolet (UV) light. It is demonstrated that the B-G hydrogel can effectively regulate the M1/M2 phenotype of macrophages, significantly promote the proliferation and migration of fibroblasts in vitro, and accelerate angiogenesis. It can boost wound closure by normalizing epidermal tissue regeneration and depositing collagen appropriately in vivo without exogenous cytokine supplementation. Overall, the B-G bioactive hydrogel can promote diabetic wound healing in a simple, economical, effective, and safe manner., (© 2022 Wiley-VCH GmbH.)

The extraction of interstitial fluid (ISF) from skin using microneedles (MNs) has attracted growing interest in recent years due to its potential for minimally invasive diagnostics and biosensors. ISF collection by absorption into a hydrogel MN patch is a promising way that requires the materials to have outstanding swelling ability. Here, a gelatin methacryloyl (GelMA) patch is developed with an 11 × 11 array of MNs for minimally invasive sampling of ISF. The properties of the patch can be tuned by altering the concentration of the GelMA prepolymer and the crosslinking time; patches are created with swelling ratios between 293% and 423% and compressive moduli between 3.34 MPa and 7.23 MPa. The optimized GelMA MN patch demonstrates efficient extraction of ISF. Furthermore, it efficiently and quantitatively detects glucose and vancomycin in ISF in an in vivo study. This minimally invasive approach of extracting ISF with a GelMA MN patch has the potential to complement blood sampling for the monitoring of target molecules from patients., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chronic inflammation and excessive reactive oxygen species (ROS) can impair diabetic wound healing. Regulatory T cells (Tregs) have emerged as a promising target to promote wound healing by regulating the immune system and supporting tissue repair through the secretion of growth factors and cytokines. However, an effective strategy for the on‐demand recruitment of Tregs for wound healing is still lacking. Here, an ROS‐scavenging Tregs‐recruiting hydrogel patch is developed for the sequential release of C─C motif chemokine 22 (CCL22) triggered by the ROS in the diabetic wound bed. The hydrogel patch is prepared by crosslinking the gelatin with ROS cleavable linker together with CCL22 (RSG‐CCL22). RSG‐CCL22 presented desirable physical properties suitable for skin regeneration purposes. In addition, the ROS scavenging feature of the RSG suppresses the differentiation of T helper 17 (Th17) cells and protects the recruited Tregs from apoptosis and oxidative stress, which maximizes their function in accelerating wound closure and promoting hair follicle regeneration in a diabetic full‐thickness skin defect mouse model. Therefore, the proposed approach provides a new therapeutic strategy for tissue regeneration and wound repair via effective recruitment of functional Tregs through ROS‐triggered on‐demand delivery. [ABSTRACT FROM AUTHOR]