The influence of a biofilm-dispersing wound gel on the wound healing process

Horseradish peroxidase/hydrogen peroxide-driven photothermally enhanced hydrogel loaded with black rice extract for treating infected skin wound

Bacterial infection of the damaged skin area hinders the wound healing process. Photothermal antibacterial therapy has attracted increasing attention. As green, safe, and possessing various bioactive properties, natural plant extracts are a good choice. However, few natural plant extracts exhibit excellent photothermal responsiveness in the near-infrared range, requiring increased concentration and radiation power to achieve satisfactory photothermal therapeutic effects. In this study, the horseradish peroxidase/hydrogen peroxide (HRP/H2O2) catalytic system was used to simultaneously oxidize anthocyanin-rich black rice extract (BRE) and hyaluronic acid-tyramine conjugate (HT), obtaining a hydrogel based on modified hyaluronic acid with enhanced photothermal ability, abbreviated as HTB. Compared to the sole HT hydrogel, the introduction and oxidation of BRE bring in the near infrared ray-responsive photothermal ability of HTB hydrogel. As a result, a lower amount of black rice extract (3 mg/mL) and reduced NIR power density (0.8 mW/cm2) are required to achieve effective photothermal therapy, further improving the hydrogel's antibacterial activity. Besides, the adhesive, coagulant, antioxidant, and anti-inflammatory properties of HTB hydrogel were also promoted. In an infected wound model in mice, the HTB hydrogel combined with photothermal treatment significantly increased CD206 expression while suppressing CD86 expression at the wound site, indicating its bactericidal and anti-inflammatory effects. Additionally, elevated levels of CD31 and α-SMA expression in the wound tissue suggest that the photothermal hydrogel dressing promotes angiogenesis. Therefore, this enzyme-crosslinked HTB hydrogel demonstrates strong photothermal antibacterial activity as well as good anti-inflammatory and pro-angiogenic effects and holds promising potential for application in treating infected wounds.

Biofilm Dispersal and Wound Infection Clearance With Preclinical Debridement Agents

Biofilms complicate wound care by causing recurrent infections that are often resistant to debridement and are highly antibiotic-tolerant. We investigated whether the addition of a biofilm dispersal agent could improve the efficacy of debridement. The previous studies have indicated that a glycoside hydrolase cocktail of alpha-amylase and cellulase can act as a potent biofilm dispersal agent. With in vitro and ex vivo Pseudomonas aeruginosa biofilm models, we compared glycoside hydrolases against other, clinically relevant, enzymatic debridement agents (papain, bromelain, and collagenase). Glycoside hydrolase biofilm dispersal was dose-dependent. However, at doses of 1% or above, glycoside hydrolases outperformed, or were comparable, to other enzymatic debridement agents. With our in vivo surgical wound infection model, we evaluated biofilm dispersal using infection dissemination as a proxy. We found that sharp debridement followed by multiple glycoside hydrolase treatments enhanced biofilm dispersal. Furthermore, a single dose of glycoside hydrolase in combination with debridement decreased infection load in acute wounds. Similarly, when we treated established 5-day-old infections, we saw a decrease in infection load and no infection dissemination. Overall, our data suggest that debridement enhances the efficacy of a topical antibiotic ointment, allowing for greater infection clearance.

Enhancing Infected Diabetic Wound Healing through Multifunctional Nanocomposite-Loaded Microneedle Patch: Inducing Multiple Regenerative Sites

Infected diabetic wound (DW) presents a prolonged and challenging healing process within the field of regenerative medicine. The effectiveness of conventional drug therapies is hindered by their limited ability to reach deep tissues and promote adequate wound healing rates. Therefore, there is an imperative to develop drug delivery systems that can penetrate deep tissues while exhibiting multifunctional properties to expedite wound healing. In this study, w e devised a soluble microneedle (MN) patch made of γ-PGA, featuring multiple arrays, which w as loaded with core-shell structured nanoparticles (NPs) known as Ag@MSN@CeO2, to enhance the healing of infected DWs. The NP comprises a cerium dioxide (CeO2) core with anti-inflammatory and antioxidant properties, a mesoporous silica NP (MSN) shell with angiogenic characteristics, and an outermost layer doped with Ag to combat bacterial infections. W e demonstrated that the MN platform loaded with Ag@MSN@CeO2 successfully penetrated deep tissues for effective drug delivery. These MN tips induced the formation of multiple regenerative sites at various points, leading to antibacterial, reactive oxygen species-lowering, macrophage ecological niche-regulating, vascular regeneration-promoting, and collagen deposition-promoting effects, thus significantly expediting the healing process of infected DWs. Considering these findings, the multifunctional MN@Ag@MSN@CeO2 patch exhibits substantial potential for clinical applications in the treatment of infected DW.

The advances of blood clots used as biomaterials in regenerative medicine

The physiologic process of blood clot formation is well understood and occurs naturally in the setting of tissue injury to achieve hemostasis and begin the process of wound healing. While the investigation of blood clots as a biomaterial is still in the early stages, there has been some research with similar biomaterials made of the components of blood clots that support the innovative idea of using an autologous blood clot as a scaffold or delivery method for therapeutic agents. Here, we review the physiology of blood clots in wound healing and how using blood clots as a biomaterial and delivery system can potentially promote wound healing, provide targeted therapeutic agent delivery and use it as an innovative tool in regenerative medicine.

The effect of mesenchymal stem cell-conditioned medium gel on burn wound healing in rat

Background and Aim: Stem cells are cells that can proliferate to form a new tissue, leading to its use in regenerative therapy. Stem cells will secrete biological factors, such as growth factors, cytokines, and other proteins to their surroundings and culture medium/conditioned medium (CM), altering tissue physiology. These factors can help wound healing, but their effect on third-degree burns is poorly understood. This research aimed to study the activity of mesenchymal stem cell-conditioned medium gel in healing and repairing third-degree burns on rats skin. Materials and Methods: Twenty-four Sprague–Dawley rats with burn wounds on the dorsal area were divided into four groups; the first group was treated with CM gel, with a concentration equivalent to 0.05% protein, the second group was treated with a placebo gel, the third group with silver sulfadiazine (SSD) cream (SSD-Burnazin contain 10 mg/g SSD), and the fourth group was not given any treatment, for 21 days, and on the final day, the rats were sacrificed, and the skins were taken. All topical treatments completely cover the wound area. Results: Wound healing process indicators observed include wound diameter, scabs' formation, blister formation, and hair growth every day. The skins taken were processed with hematoxylin-eosin and Masson's trichrome staining. The indicators studied include neutrophil infiltration, mononuclear cell infiltration, neovascularization, collagen area, and re-epithelization ratio. Conclusion: CM shows better wound healing than other groups and faster hair growth.