A kaolin/calcium incorporated shape memory and antimicrobial chitosan-dextran based cryogel as an efficient haemostatic dressing for uncontrolled hemorrhagic wounds

A self-elastic chitosan sponge integrating active and passive hemostatic mechanisms for effectively managing uncontrolled coagulopathic hemorrhage

Developing a self-elastic sponge integrating active and passive hemostatic mechanisms for the effective management of uncontrolled coagulopathic hemorrhage remains a challenge. We here developed a chitosan-based sponge by integrating freeze-drying, chemical decoration of alkyl chains and phosphate groups, and physical loading of thrombin. The sponge exhibited high mechanical strength, self-elasticity, and rapid shape recovery. The sponge facilitated blood cell adhesion, aggregation, and activation through hydrophobic and electrostatic interactions, as well as accelerated blood clotting. The sponge exhibited higher efficacy than commercial gauze and gelatin sponge in managing uncontrolled hemorrhage from heparinized rat tail amputation, liver superficial injury, and liver perforating wound models. In addition, the sponge exhibited favorable biodegradability and biocompatibility. These findings revealed that the developed sponge holds great potential as a novel hemostat for effectively managing uncontrolled coagulopathic hemorrhage from superficial and perforating wounds.

Recent advances in the application of clay-containing hydrogels for hemostasis and wound healing

INTRODUCTION

Immediate control of bleeding and anti-infection play important roles in wound management. Multiple organ dysfunction syndrome and death may occur if persistent bleeding, hemodynamic instability, and hypoxemia are not addressed. The combination of clay and hydrogel provides a new outlet for wound hemostasis. In this review, the current research progress of hydrogel/clay composite hemostatic agents was reviewed.

AREAS COVERED

This paper summarizes the characteristics of several kinds of clay including kaolinite, montmorillonite, laponite, sepiolite, and palygorskite. The advantages and disadvantages of its application in hemostasis were also summarized. Future directions for the application of hydrogel/clay composite hemostatic agents are presented.

EXPERT OPINION

Clay can activate the endogenous hemostatic pathway by increasing blood cell concentration and promoting plasma absorption to accelerate the hemostasis. Clay is antimicrobial due to the slow release of metal ions and has a rich surface charge with a high affinity for proteins and cells to promote tissue repair. Hydrogels have some properties such as good biocompatibility, strong adhesion, high stretchability, and good self-healing. Despite promising advances, hydrogel/clay composite hemostasis remains a limitation. Therefore, more evidence is needed to further elucidate the risk factors and therapeutic effects of hydrogel/clay in hemostasis and wound healing.

Synergistic bactericidal combinations between gentamicin and chitosan capped ZnO nanoparticles: A promising strategy for repositioning this first-line antibiotic

Gentamicin (GEN), a widely used broad-spectrum antibiotic, faces challenges amid the global emergency of antimicrobial resistance. This study aimed to explore the synergistic effects of zinc oxide nanoparticles (ZnO NPs) in combination with GEN on the bactericidal activity against various bacterial strains. Results showed ZnO NPs with MICs ranging from 0.002 to 1.5 μg/mL, while the precursor salt displayed a MIC range of 48.75-1560 μg/mL. Chitosan (CS)-capped ZnO NPs exhibited even lower MICs than their uncapped counterparts, with the CS-capped synthesized ZnO NPs demonstrating the lowest values. Minimal bactericidal concentrations (MBC) aligned with MIC trends. Combinations of CS-capped synthesized ZnO NPs and GEN proved highly effective, inhibiting bacterial growth at significantly lower concentrations than GEN or ZnO NPs alone. This phenomenon may be attributed to the conformation of CS on the ZnO NPs' surface, enhancing the positive particle surface charge. This possibly facilitates a more effective interaction between ZnO NPs and microorganisms, leading to increased accumulation of zinc and GEN within bacterial cells and an overproduction of reactive oxygen species (ROS). It's crucial to note that, while this study did not specifically involve resistant strains, its primary focus remains on enhancing the overall antimicrobial activity of gentamicin. The research aims to contribute to addressing the global challenge of antimicrobial resistance, recognizing the urgent need for effective strategies to combat this critical issue. The findings, particularly the observed synergy between ZnO NPs and GEN, hold significant implications for repositioning the first-line antibiotic GEN.

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device

Impairment of intestinal epithelium is a typical feature of inflammatory bowel disease (IBD) that causes leakage of bacteria and antigens from the intestinal lumen and thus results in persistent immune activation. Hence, healing and regeneration of the damaged gut mucosa is a promising therapeutic approach to achieve deep remission in IBD. Currently, available systemic therapies have moderate effects and are often associated with numerous side effects and malignancies. In this study, we aimed to develop a topical therapy by chemically conjugating a temperature-responsive polymer, i.e., poly(N-isopropylacrylamide), along with hyaluronic acid to obtain a sprayable therapeutic formulation that upon colon instillation adheres to the damaged gut mucosa due to its temperature-induced phase transition and mucoadhesive properties. An ex vivo adhesion experiment demonstrates that this therapeutic formulation forms a thin physical coating on the mucosal lining at a physiological temperature within 5 min. Physicochemical characterization of (P(NIPAM-co-NTBAM)-HA) established this formulation to be biocompatible, hemo-compatible, and non-immunogenic. Prednisolone was encapsulated within the polymer formulation to achieve maximum therapeutic efficacy in the case of IBD-like conditions as assessed in a custom-fabricated perfusion-based ex vivo model system. Histological analysis suggests that the prednisolone-encapsulated polymer formulation nearly restored the mucosal architecture after 2,4,6-trinitrobenzenesulfonic acid-induced damage. Furthermore, a significant (p ≤ 0.001) increase in mRNA levels of Muc-2 and ZO-1 in treated groups further confirmed the mucosal epithelial barrier restoration.