Electrospun nanofiber membranes for rapid liver hemostasis via N-alkylated chitosan doped chitosan/PEO

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.

All-aqueous microfluidic fabrication of calcium alginate/alkylated chitosan core-shell microparticles with time-sequential functions for promoting whole-stage wound healing

Wound healing comprises a series of complex physiological processes, including hemostasis, inflammation, cell proliferation, and tissue remodeling. Designing new functional biomaterials by biological macromolecules with tailored therapeutic effects to precisely match the unique requirements of each stage is cherished but rarely discussed. Here, we employ all-aqueous microfluidics to fabricate multifunctional core-shell microparticles aimed at promoting whole-stage wound healing. These microparticles feature a core comprising calcium alginate, cellulose nanocrystals and epidermal growth factor, surrounded by a shell made of alkylated chitosan, alginate, and ciprofloxacin (EGF + CNC@Ca-ALG/CIP@ACS core-shell microparticles, D-CSMP). Response surface methodology (RSM) with a combination of central composite rotatable design (CCRD) is used to meticulously optimize the fabrication processes, endowing the resulting D-CSMP with superior capabilities for efficiently encapsulating and controlled releasing CIP and EGF tailored to each stage aligning the healing timeline. The developed D-CSMP demonstrate notable time-sequential functionalities, including promoting blood coagulation, enhancing hemostasis, and exerting antibacterial effects. Furthermore, in a skin injury model, D-CSMP significantly expedite and enhance the chronic wound healing process. In conclusion, our core-shell microparticles with notable time-sequential functions present a versatile and robust approach for wound treatment and related biomedical applications.

Dandelion-shaped strontium-gallium microparticles for the hierarchical stimulation and comprehensive regulation of wound healing

The management of full-thickness skin injuries continues to pose significant challenges. Currently, there is a dearth of comprehensive dressings capable of integrating all stages of wound healing to spatiotemporally regulate biological processes following full-thickness skin injuries. In this study, we report the synthesis of a dandelion-shaped mesoporous strontium-gallium microparticle (GE@SrTPP) achieved through dopamine-mediated strontium ion biomineralization and self-assembly, followed by functionalization with gallium metal polyphenol networks. As a multifunctional wound dressing, GE@SrTPP can release bioactive ions in a spatiotemporal manner akin to dandelion seeds. During the early stages of wound healing, GE@SrTPP demonstrates rapid and effective hemostatic performance while also exhibiting antibacterial properties. In the inflammatory phase, GE@SrTPP promotes M2 polarization of macrophages, suppresses the expression of pro-inflammatory factors, and decreases oxidative stress in wounds. Subsequently, during the stages of proliferation and tissue remodeling, GE@SrTPP facilitates angiogenesis through the activation of the Hypoxia-inducible factor-1α/vascular endothelial growth factor (HIF-1α/VEGF) pathway. Analogous to the dispersion and rooting of dandelion seeds, the root-like new blood vessels supply essential nutrients for wound healing. Ultimately, in a rat chronic wound model, GE@SrTPP achieved successful full-thickness wound repair. In summary, these dandelion-shaped GE@SrTPP microparticles demonstrate comprehensive regulatory effects in managing full-thickness wounds, making them highly promising materials for clinical applications.

Multifunctional nanofibrous scaffolds for enhancing full-thickness wound healing loaded with Bletilla striata polysaccharides

The considerable challenge of wound healing remains. In this study, we fabricated a novel multifunctional core-shell nanofibrous scaffold named EGF@BSP-CeO2/PLGA (EBCP), which is composed of Bletilla striata polysaccharide (BSP), Ceria nanozyme (CeO2) and epidermal growth factor (EGF) as the core and poly(lactic-co-glycolic acid) (PLGA) as the shell via an emulsion electrospinning technique. An increase in the BSP content within the scaffolds corresponded to improved wound healing performance. These scaffolds exhibited increased hydrophilicity and porosity and improved mechanical properties and anti-UV properties. EBCP exhibited sustained release, and the degradation rate was <4 % in PBS for 30 days. The superior biocompatibility was confirmed by the MTT assay, hemolysis, and H&E staining. In addition, the in vitro results revealed that, compared with the other groups, the EBCP group presented excellent antioxidant and antibacterial effects. More importantly, the in vivo results indicated that the wound closure rate of the EBCP group reached 94.0 % on day 10 in the presence of H2O2. The results demonstrated that EBCP could comprehensively regulate the wound microenvironment, possess hemostatic abilities, and significantly promote wound healing. In conclusion, the EBCP is promising for facilitating the treatment of infected wounds and represents a potential material for clinical applications.

NIR-responsive electrospun nanofiber dressing promotes diabetic-infected wound healing with programmed combined temperature-coordinated photothermal therapy

BACKGROUND

Diabetic wounds present significant challenges, specifically in terms of bacterial infection and delayed healing. Therefore, it is crucial to address local bacterial issues and promote accelerated wound healing. In this investigation, we utilized electrospinning to fabricate microgel/nanofiber membranes encapsulating MXene-encapsulated microgels and chitosan/gelatin polymers.

RESULTS

The film dressing facilitates programmed photothermal therapy (PPT) and mild photothermal therapy (MPTT) under near-infrared (NIR), showcasing swift and extensive antibacterial and biofilm-disrupting capabilities. The PPT effect achieves prompt sterilization within 5 min at 52 °C and disperses mature biofilm within 10 min. Concurrently, by adjusting the NIR power to induce local mild heating (42 °C), the dressing stimulates fibroblast proliferation and migration, significantly enhancing vascularization. Moreover, in vivo experimentation successfully validates the film dressing, underscoring its immense potential in addressing the intricacies of diabetic wounds.

CONCLUSIONS

The MXene microgel-loaded nanofiber dressing employs temperature-coordinated photothermal therapy, effectively amalgamating the advantageous features of high-temperature sterilization and low-temperature promotion of wound healing. It exhibits rapid, broad-spectrum antibacterial and biofilm-disrupting capabilities, exceptional biocompatibility, and noteworthy effects on promoting cell proliferation and vascularization. These results affirm the efficacy of our nanofiber dressing, highlighting its significant potential in addressing the challenge of diabetic wounds struggling to heal due to infection.

Degradation profiles of the poly(ε-caprolactone)/silk fibroin electrospinning membranes and their potential applications in tissue engineering

Degradation profiles are critical for the optimal application of electrospun polymer nanofibers in tissue regeneration, wound healing, and drug delivery systems. In this study, natural and synthetic polymers and their composites were subjected to in vivo transplantation and in vitro treatment with lipases, macrophages, and acetic acid to evaluate their degradation patterns. The effects of environmental stimulation, surface wettability, and polymer components on the degradation profiles of the electrospinning poly(ε-caprolactone)/silk fibroin (PCL/SF) nanofibers were first evaluated. In vivo degradation study demonstrated that bulk degradation, characterized by the transition from microfibers to nanofibers, and surface erosion, characterized by fusion between the microfibers or direct erosion from both ends of the microfibers, occurred in the electrospun membranes; however, bulk degradation dominated their overall degradation. Furthermore, the degradation rates of the electrospun PCL/SF membranes varied according to the composition, morphology, and surface wettability of the composite membranes. After the incorporation of silk fibroin (SF), the degradation rate of the SF/PCL composite membranes was faster, accompanied by larger values of weight loss and molecular weight (Mw) loss when compared with that of the pure poly(ε-caprolactone) (PCL) membrane, indicating a close relationship between degradation rate and hydrophilicity of the electrospinning membranes. The in vitro experimental results demonstrated that enzymes and oxidation partially resulted in the surface erosion of the PCL/SF microfibers. Consequently, bulk degradation and surface erosion coordinated with each other to enhance the hydrophilicity of the electrospinning membranes and accelerate the in vivo degradation.

Advances in chitosan and chitosan derivatives for biomedical applications in tissue engineering: An updated review

In recent years, chitosan (CS) has received much attention as a functional biopolymer for various applications, especially in the biomedical field. It is a natural polysaccharide created by the chemical deacetylation of chitin (CT) that is nontoxic, biocompatible, and biodegradable. This natural polymer is difficult to process; however, chemical modification of the CS backbone allows improved use of functional derivatives. CS and its derivatives are used to prepare hydrogels, membranes, scaffolds, fibers, foams, and sponges, primarily for regenerative medicine. Tissue engineering (TE), currently one of the fastest-growing fields in the life sciences, primarily aims to restore or replace lost or damaged organs and tissues using supports that, combined with cells and biomolecules, generate new tissue. In this sense, the growing interest in the application of biomaterials based on CS and some of its derivatives is justifiable. This review aims to summarize the most important recent advances in developing biomaterials based on CS and its derivatives and to study their synthesis, characterization, and applications in the biomedical field, especially in the TE area.