Photothermal enhanced antibacterial chitosan-based polydopamine composite hydrogel for hemostasis and burn wound repairing

Recent advances in modifications, biotechnology, and biomedical applications of chitosan-based materials: A review

Chitosan, a natural polysaccharide with recognized biocompatibility, non-toxicity, and cost-effectiveness, is primarily sourced from crustacean exoskeletons. Its inherent limitations such as poor water solubility, low thermal stability, and inadequate mechanical strength have hindered its widespread application. However, through modifications, chitosan can exhibit enhanced properties such as water solubility, antibacterial and antioxidant activities, adsorption capacity, and film-forming ability, opening up avenues for diverse applications. Despite these advancements, realizing the full potential of modified chitosan remains a challenge across various fields. The purpose of this review article is to conduct a comprehensive evaluation of the chemical modification techniques of chitosan and their applications in biotechnology and biomedical fields. It aims to overcome the inherent limitations of chitosan, such as low water solubility, poor thermal stability, and inadequate mechanical strength, thereby expanding its application potential across various domains. This review is structured into two main sections. The first part delves into the latest chemical modification techniques for chitosan derivatives, encompassing quaternization, Schiff base formation, acylation, carboxylation, and alkylation reactions. The second part provides an overview of the applications of chitosan and its derivatives in biotechnology and biomedicine, spanning areas such as wastewater treatment, the textile and food industries, agriculture, antibacterial and antiviral activities, drug delivery systems, wound dressings, dental materials, and tissue engineering. Additionally, the review discusses the challenges associated with these modifications and offers insights into potential future developments in chitosan-based materials. This review is anticipated to offer theoretical insights and practical guidance to scientists engaged in biotechnology and biomedical research.

Antibacterial betaine modified chitosan-based hydrogel with angiogenic property for photothermal enhanced diabetic wound repairing

Chronic diabetes wound repairing is still a huge challenge in clinical practice. High concentration of reactive oxygen species and vascular disfunction are the main factors hindering the recovery of diabetes wounds. This research grafted betaine onto chitosan (CSBT) to enhance the antibacterial property and the CSBT was cross-linked with PEO90 dialdehyde (PEO DA) to prepare hydrogel with Ca2+ loading to promote the coagulation. The polydopamine nanoparticles (PDA NPs) with photothermal property and antioxidant property was composited to the hydrogel and deferoxamine (DFO) was loaded to fabricate the multifunctional CBPCa/PDA/DFO hydrogel to promote vascular regeneration in combination with photothermal antibacterial performance for the diabetes wounds treatment. The CBPCa/PDA/DFO hydrogel showed good mechanical strength, injectability, anti-inflammatory property and coagulation performance. Furthermore, the antibacterial effect of chitosan based hydrogel was enhanced with near infrared (NIR) stimulated photothermal treatment. Combined with the photothermal effect and the angiogenic drug DFO release, the CBPCa/PDA/DFO hydrogel significantly enhanced vascular regeneration and reduced the inflammation in the in vivo wound repairing experiment. As a result, the CBPCa/PDA/DFO hydrogel may provide a promising therapeutic platform for diabetic trauma repairing.

Antibacterial properties and biological activity of 3D-printed titanium alloy implants with a near-infrared photoresponsive surface

PURPOSE

SLM 3D printing technology is one of the most widely used implant-making technologies. However, the surfaces of the implants are relatively rough, and bacteria can easily adhere to them; increasing the risk of postoperative infection. Therefore, we prepared a near-infrared photoresponsive nano-TiO2 coating on the surface of an SLM 3D-printed titanium alloy sheet (Ti6Al4V) via a hydrothermal method to evaluate its antibacterial properties and biocompatibility.

METHODS

Using SLM technology, titanium alloy sheets were 3D printed, and a nano-TiO2 coating was prepared on its surface via a hydrothermal method to obtain Ti6Al4V@TiO2. The surface morphology, physicochemical properties, and photothermal response of the samples were observed. The Ti6Al4V groups and Ti6Al4V@TiO2 groups were cocultured with S. aureus and E. coli and exposed to 808 nm NIR light (0.8 W/cm2) and viable plate count experiments and live/dead bacterial staining were used to assess their in vitro antibacterial properties.

RESULTS

The hydrophilicity of the nano-TiO2 coating sample significantly improved and the sample exhibited an excellent photothermal response. The temperature reached 46.9± 0.32 °C after 15 min of irradiation with 808 nm NIR light (0.8 W/cm2). The Ti6Al4V group showed significant antibacterial properties after irradiation with 808 nm NIR light, and the Ti6Al4V@TiO2 group also had partial antibacterial ability without irradiation. After irradiation with 808 nm NIR light, the Ti6Al4V@TiO2 group showed the strongest antibacterial properties, reaching 90.11± 2.20% and 90.60± 1.08% against S. aureus and E. coli, respectively.

CONCLUSIONS

A nano-TiO2 coating prepared via a hydrothermal method produced synergistic antibacterial effects after NIR light irradiation.

Composite Polysaccharide Hydrogel Loaded with Scutellaria baicalensis Extract for Diabetic Wound Treatment

Diabetic wounds present significant burdens to both patients and the healthcare system due to their prolonged inflammatory phase and adverse microenvironment. Traditional Chinese medicine (TCM), particularly Scutellaria baicalensis extract (SE), has shown promise in wound healing. Herein, sesbania gum (SG) was oxidized and formed hydrogel with carboxymethyl chitosan (CMCS) through the imine bond. Then, SE was loaded into the hydrogel as a wound dressing (CMCS-OSG@SE hydrogel). In vitro experiments demonstrated the mechanical properties and ROS scavenging efficiency of the hydrogel, as well as the release of SE and its biocompatibility. In an vivo study, diabetic mice with S. aureus infection were used, and the CMCS--OSG@SE hydrogel dressing accelerated wound healing by promoting epidermal regeneration and collagen deposition. This composite polysaccharide hydrogel loaded with SE shows great potential for diabetic wound treatment.