Dynamic Microenvironment-Adaptable Hydrogel with Photothermal Performance and ROS Scavenging for Management of Diabetic Ulcer

Aldehyde-modified sodium alginate/gelatin-based bacteriophage-loaded multifunctional hydrogel for promoting the healing of multidrug-resistant bacterial-infected wounds

Multidrug-resistant bacterial infections in skin injuries are hard to repair. There is an urgent need to develop new antibacterials, antibiofilm formation, and immunomodulatory wound dressing. In this study, we produced a bacteriophage-loaded multifunctional hydrogel consisting of aldehyde-modified sodium alginate (ADA), gelatin (GEL), and carboxymethyl chitosan (CMCS) through a Schiff base reaction and borax complexation. These post-reactive ADA/GEL/CMCS/Phage (AGCP) hydrogels, particularly the AGCP3 hydrogel, boast a porous structure, high swelling rate, effective hemostasis, controlled degradation, good rheological properties, and strong antibacterial activity. Furthermore, the hydrogel developed in this study can sustainably release various bacteriophages targeting the bacteria responsible for major skin infections, thereby enhancing antibacterial activity and preventing bacterial biofilm formation. Besides, cytotoxicity and cell proliferation demonstrated that the hydrogel, comprising three polysaccharides, ADA, GEL, and CMCS, facilitates skin tissue regeneration by enhancing cellular proliferation and migration. The AGCP hydrogel enhanced healing and controlled inflammation in bacterial-infected wounds, as evidenced by wound closure, collagen deposition, and quantitative reverse transcription polymerase chain reaction results. In conclusion, the AGCP3 hydrogel exhibits strong antibacterial properties, excellent expands, biocompatibility, hemostatic properties, and a controlled release of bacteriophages, making it ideal for universal bacteriophage delivery systems and wound dressings for skin wounds infected with multidrug-resistant bacteria.

Design and biofabrication of barnacle and spider silk protein decorated composite bacterial cellulose for diabetic wound healing

Delayed healing of wounds in diabetics is mainly due to tissue inflammation, poor vasculature, lack of neovascularization, and bacterial infection. Therefore, a therapeutic protocol that disrupts this cycle and speeds healing is urgently needed. Despite attempts to enhance wound dressing effectiveness through hydrogels with diverse complexes such as bacterial cellulose (BC) combined with chitosan, BC/ chitosan/hyaluronic acid, and BC/chitosan/collagen, the toughness and adhesion properties of hydrogel remain constrained, leading to inadequate and uncontrollable wound healing. To address the challenge, we have devised an innovative solution by integrating barnacle cement protein (cp19k) and spider silk protein (major ampullate spidroin 1, MaSp1) into a BC matrix, complemented by chitosan. This development has led to the creation of a novel BC-based composite hydrogel BC/cp19k-MaSp1/C150k. The composite hydrogel stands out with its remarkable mechanical (3.92 Mpa) and adhesion properties (8.4 kPa) compared to its BC/C150k counterpart. Meanwhile, the BC/cp19k-MaSp1/C150k hydrogel also demonstrated antimicrobial activity, coagulation, and biocompatibility. The BC/cp19k-MaSp1/C150k hydrogel showed an exceptional capacity to enhance wound healing in a diabetic rat model, achieving a significant wound closure rate of over 98 % on day 14 when compared to BC and commercially available dressing 3 M™ Tegaderm™. This advancement holds significant promise in revolutionizing wound management for diabetics.

Smart self-healing hydrogel wound dressings for diabetic wound treatment

Diabetic wounds are difficult to treat clinically because they heal poorly, often leading to severe complications such as infections and amputations. Hydrogels with smart self-healing properties show great promise for treating diabetic wounds. These hydrogels are capable of continuously and dynamically responding to changes in the wound environment, feature improved mechanical qualities and the capacity to self-heal damage. We explore the latest developments in smart self-healing hydrogels for diabetic wound healing in this review. First, we systematically summarize the obstacles in treating diabetic wounds. We then highlighted the significance of smart self-healing hydrogels, explaining their stimulus-responsive mechanisms and self-healing design approaches, along with their applications in addressing these challenges. Finally, we discussed the unresolved obstacles and potential avenues for future research. We anticipate that this review will facilitate the continued refinement of smart self-healing hydrogels for diabetic wound dressings, aiming for broader clinical adoption.

Tissue-Adhesive and Antibacterial Hydrogel Promotes MDR Bacteria-Infected Diabetic Wound Healing via Disrupting Bacterial Biofilm, Scavenging ROS and Promoting Angiogenesis

Effective treatment of diabetic wounds remains challenging because of multidrug-resistant (MDR) bacterial infections, excessive oxidative stress, and impaired angiogenesis. In this study, a tissue-adhesive and antibacterial hydrogel incorporating MXene and deferoxamine (DFO)-loaded microspheres is developed for the treatment of MDR bacteria-infected diabetic wounds. The hydrogel is built based on covalent crosslinking between ε-poly(L-lysine) and o-phthalaldehyde-terminated four-arm poly(ethylene glycol). The hydrogel exhibited excellent mechanical properties, tissue adhesion strength, biocompatibility, and biodegradability. Under near-infrared (NIR) irradiation, the MXene converted light into heat and elevated the local temperature rapidly, enabling the rapid disintegration of MDR bacterial biofilms. Simultaneously, the hydrogel exerted inherent antibacterial activity, persistently killing planktonic bacteria, and effectively controlling wound infections. The encapsulated DFO is then released from the hydrogel in a sustained and controlled manner, and promoted angiogenesis during diabetic wound healing. Additionally, MXenes can scavenge excessive reactive oxygen species and alleviate wound inflammation. In the methicillin-resistant Staphylococcus aureus-infected diabetic wound model in mice, the composite hydrogel along with NIR irradiation efficiently reduced the infectious bacteria, and accelerated the wound healing by promoting angiogenesis and alleviating inflammation. This composite hydrogel has great clinical potential for the treatment of diabetic wounds, particularly in challenging healing environments involving motion and infection.

Self-Cascade of ROS/Glucose-Scavenging Immunomodulatory Hydrogels for Programmed Therapeutics of Infected Diabetic Ulcers via Nrf2/NF-κB Pathway

Diabetic ulcers (DUs) are characterized by a microenvironment with high oxidative stress, high blood glucose levels, and recalcitrant bacterial infections. This microenvironment is accompanied by long-term suppression of endogenous antioxidant systems, which makes their clinical management extremely challenging. To address this issue, a hybridized novel gold-palladium (AuPd) nanoshell of the injectable/injectable hydrogel system UiO/AuPdshells/BNN6/PEG@Gel (UAPsBP@Gel) is developed. The system is capable of acting as a nitric oxide (NO) reactor utilizing synergistic therapy that harnesses NIR-II light-triggered photothermal effects and controlled release of NO gas for synergistic treatment to eradicate biofilm infections at different depths. The AuPd nanoshells exhibits superoxide dismutase (SOD)-, glucose oxidase (GOx)-, and catalase (CAT)-like activities, enabling self-cascade process for scavenging both reactive oxygen species (ROS) and glucose. This activity reshapes the DUs microenvironment, switches on the endogenous antioxidant Nrf2/HO-1 pathway and inhibits the NF-κB pathway, promotes macrophage polarization toward the anti-inflammatory M2 phenotype, and reduces oxidative stress, resulting in efficient immunomodulation. In vitro/in vivo results demonstrate that the UAPsBP@Gel can multifacetedly enhance the epithelial rejuvenation process through wound hemostasis, pro-cellular migration and vascularization. These results highlight that a programmed therapeutic based on UBAPsP@Gel tailored to the different stages of infected DUs can meet complex clinical needs.

Enhanced diabetic foot ulcer treatment with a chitosan-based thermosensitive hydrogel loaded self-assembled multi-functional nanoparticles for antibacterial and angiogenic effects

Inhibiting bacterial growth and promoting angiogenesis are essential for enhancing wound healing in diabetic patients. Excessive oxidative stress at the wound site can also lead to an accumulation of reactive oxygen species. To address these challenges, a smart thermosensitive hydrogel loaded with therapeutic agents was developed. This formulation features self-assembled nanoparticles named CIZ, consisting of chlorogenic acid (CA), indocyanine green (ICG), and zinc ions (Zn2+). These nanoparticles are loaded into a chitosan-β-glycerophosphate hydrogel, named CIZ@G, which enables rapid gel formation under photothermal effects. The hydrogel demonstrates good biocompatibility and effectively releases drugs into diabetic foot ulcers (DFU) wound. Benefiting from the dual actions of CA and zinc ions, the hydrogel exhibits potent antioxidative and anti-inflammatory effects, enhances the expression of vascular endothelial growth factor (VEGF) and Platelet endothelial cell adhesion molecule-1 (CD31), and promotes angiogenesis. Both in vitro and in vivo experiments confirm that CIZ@G can effectively inhibit the growth of Staphylococcus aureus post-laser irradiation and accelerate wound remodeling within 14 days. This approach offers a new strategy for the treatment of diabetic foot ulcers (DFU), potentially transforming patient care in this challenging clinical area.

Facile Reactive Oxygen Species-Scavenging Supramolecular Hydrogel to Promote Diabetic Wound Healing

Chronic wound healing impairment is a significant complication in diabetes. Hydrogels that maintain wound moisture and enable sustained drug release have become prominent for enhancing chronic wound care. Particularly, hydrogels that respond to reactive oxygen species (ROS) are sought-after for their dual capacity to mitigate ROS and facilitate controlled drug delivery at the wound site. We have strategically designed an ROS-responsive and scavenging supramolecular hydrogel composed of the simple hexapeptide Glu-Phe-Met-Phe-Met-Glu (EFM). This hydrogelator, composed solely of canonical amino acids without additional ROS-sensitive motifs, forms a hydrogel rapidly upon sonication. Interaction with ROS leads to the oxidation of Met residues to methionine sulfoxide, triggering hydrogel disassembly and consequent payload release. Cellular assays have verified their biocompatibility and efficacy in promoting cell proliferation and migration. In vivo investigations underscore the potential of this straightforward hydrogel as an ROS-scavenger and drug delivery vehicle, enhancing wound healing in diabetic mice. The simplicity and effectiveness of this hydrogel suggest its broader biomedical applications in the future.

Photothermal hydrogels for infection control and tissue regeneration

In this review, we report investigating photothermal hydrogels, innovative biomedical materials designed for infection control and tissue regeneration. These hydrogels exhibit responsiveness to near-infrared (NIR) stimulation, altering their structure and properties, which is pivotal for medical applications. Photothermal hydrogels have emerged as a significant advancement in medical materials, harnessing photothermal agents (PTAs) to respond to NIR light. This responsiveness is crucial for controlling infections and promoting tissue healing. We discuss three construction methods for preparing photothermal hydrogels, emphasizing their design and synthesis, which incorporate PTAs to achieve the desired photothermal effects. The application of these hydrogels demonstrates enhanced infection control and tissue regeneration, supported by their unique photothermal properties. Although research progress in photothermal hydrogels is promising, challenges remain. We address these issues and explore future directions to enhance their therapeutic potential.

Microenvironmental dynamics of diabetic wounds and insights for hydrogel-based therapeutics

The rising prevalence of diabetes has underscored concerns surrounding diabetic wounds and their potential to induce disability. The intricate healing mechanisms of diabetic wounds are multifaceted, influenced by ambient microenvironment, including prolonged hyperglycemia, severe infection, inflammation, elevated levels of reactive oxygen species (ROS), ischemia, impaired vascularization, and altered wound physicochemical properties. In recent years, hydrogels have emerged as promising candidates for diabetic wound treatment owing to their exceptional biocompatibility and resemblance to the extracellular matrix (ECM) through a three-dimensional (3D) porous network. This review will first summarize the microenvironment alterations occurring in the diabetic wounds, aiming to provide a comprehensive understanding of its pathogenesis, then a comprehensive classification of recently developed hydrogels will be presented, encompassing properties such as hypoglycemic effects, anti-inflammatory capabilities, antibacterial attributes, ROS scavenging abilities, promotion of angiogenesis, pH responsiveness, and more. The primary objective is to offer a valuable reference for repairing diabetic wounds based on their unique microenvironment. Moreover, this paper outlines potential avenues for future advancements in hydrogel dressings to facilitate and expedite the healing process of diabetic wounds.