An antibacterial Multi-Layered scaffold fabricated by 3D printing and electrospinning methodologies for skin tissue regeneration

"Double-sided protector" Janus hydrogels for skin and mucosal wound repair: applications, mechanisms, and prospects

Skin and mucous membranes serve as crucial barrier tissues within the human body. Defective wound healing not only inflicts pain but also heightens the risk of infection and impairs immune function. Janus hydrogels possess two-sided distinct asymmetric structures that endow them with diverse properties such as high water absorbency, flexibility, anti-adhesion ability etc. These hydrogels also exhibit great potential in biofluid transport, drug delivery and promoting tissue repair. Currently, research efforts predominantly concentrate on the preparation techniques, properties, and biomedical applications. This review summarized its structural characteristics and different forms of designations, and focused on the possible mechanisms, the existing problems and improvement strategies for the skin and mucous tissues wound, aiming to provide new design ideas for repairing complex skin and mucous membrane tissue defects.

Insulin/PHMB-grafted sodium alginate hydrogels improve infected wound healing by antibacterial-prompted macrophage inflammatory regulation

BACKGROUND

Non-healing chronic wounds with high susceptibility to infection represent a critical challenge in modern healthcare. While growth factors play a pivotal role in regulating chronic wound repair, their therapeutic efficacy is compromised in infected microenvironments. Current wound dressings inadequately address the dual demands of sustained bioactive molecule delivery and robust antimicrobial activity.

RESULTS

In this study, we developed a sodium alginate hydrogel (termed P-SA/Ins), which incorporated polyhexamethylene biguanide (PHMB) grafting and long-acting glargine insulin loading. P-SA/Ins exhibited the favorable physicochemical performance, biocompatibility and antibacterial efficacy against both Gram-negative and Gram-positive pathogens through inhibition of bacterial proliferation and biofilm formation. Glargine insulin was applied to prolonged insulin delivery. P-SA/Ins treatment attenuated S. aureus induced pro-inflammatory cytokine cascades in macrophages. The evaluation in vivo using a rat model with S. aureus infected wound demonstrated that P-SA/Ins significantly enhanced wound healing and optimized skin barrier through antimicrobial-mediated modulation of macrophage polarization and subsequent inflammatory cytokine profiling.

CONCLUSIONS

Our findings demonstrate that P-SA/Ins promotes wound healing and restores epidermal barrier integrity, indicating its potential as a therapeutic dressing for chronic wound healing, particularly in cases with infection risk.

AI-Guided Design of Antimicrobial Peptide Hydrogels for Precise Treatment of Drug-resistant Bacterial Infections

Traditional biomaterial development lacks systematicity and predictability, posing significant challenges in addressing the intricate engineering issues related to infections with drug-resistant bacteria. The unprecedented ability of artificial intelligence (AI) to manage complex systems offers a novel paradigm for materials development. However, no AI model currently guides the development of antibacterial biomaterials based on an in-depth understanding of the interplay between biomaterials and bacteria. In this study, an AI-guided design platform (AMP-hydrogel-Designer) is developed to generate antibacterial biomaterials. This platform utilizes generative design and multi-objective constrained optimization to generate a novel thiol-containing high-efficiency antimicrobial peptide (AMP), that is functionally coupled with hydrogel to form a complex network structure. Additionally, Cu-modified barium titanate (Cu-BTO) is incorporated to facilitate further complex cross-linking via Cu2+/SH coordination to produce an AI-AMP-hydrogel. In vitro, the AI-AMP-hydrogel exhibits > 99.99% bactericidal efficacy against Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). Furthermore, Cu-BTO converts mechanical stimulation into electrical signals, thereby promoting the expression of growth factors and angiogenesis. In a rat model with dynamic wounds, the AI-AMP hydrogel significantly reduces the MRSA load and markedly accelerates wound healing. Therefore, the AI-guided biomaterial development strategy offers an innovative solution to precisely treat drug-resistant bacterial infections.

Deferoxamine-Loaded Trilayer Scaffold Containing Propolis and Sulfated Polysaccharides Promotes In Vivo Wound Healing through Angiogenesis Stimulation

The skin exhibits a hierarchical structure, and the application of tissue engineering techniques is recommended for the treatment of severe cutaneous injuries. To biologically mimic the structural characteristics of the distinct layers of the skin, the utilization of multilayered scaffolds has become a prominent approach. In the current study, an asymmetric trilayered scaffold was fabricated, consisting of a middle layer (ML) composed of 3D printed poly(vinyl alcohol)-carrageenan (PVA.Crg), a top layer (TL) of nanofibrous polycaprolactone-propolis (PCL.Pp), and a bottom layer (BL) of poly(vinyl alcohol)-fucoidan-deferoxamine (PVA.Fu.Def) nanofibers. It was indicated that the tensile strength and elastic modulus of the trilayer scaffold were significantly higher compared to other samples. The in vitro degradation rate of the studied scaffolds as well as the release of Def from the trilayer scaffold after 7 days were quantified within the range of 36-40 and 91.1%, respectively. The release of Def did not induce cytotoxicity and chicken chorioallantoic membrane assay revealed that the release of Def remarkably enhanced angiogenesis. Furthermore, the in vivo examinations exhibited the fastest re-epithelialization in the group treated with the trilayer scaffold containing Def. The findings of this study suggest the potential application of the fabricated trilayer scaffold as a skin substitute or wound dressing.

Nanodiamond: a multifaceted exploration of electrospun nanofibers for antibacterial and wound healing applications

In this review, we explore the exciting potential of nanodiamonds (NDs) as innovative materials for future wound dressings. These materials aim to tackle important issues in wound care and offer fresh solutions. While NDs show promising mechanical and structural properties, their full potential in wound healing applications is still not fully explored. We emphasize their unique features-like high surface area, the dispersion of functional groups, and excellent purity-which contribute to their mechanical stability, adhesion, growth, and movement-all critical for effective wound healing and tissue repair. We also focused on modifying the surface of these particles using various functionalization, which can enhance their biocompatibility, antibacterial properties, heat conductivity, and wettability. This positions NDs as a powerful tool for improving chronic wound care in the future. However, there are notable challenges when it comes to scaling up ND-based nanofiber matrices, which currently limits the electrospinning process for mass production. Also, issues with the physical and chemical stability of ND-based nanofibers when interacting with cells need to be resolved to guarantee long-lasting effectiveness. In this study, we tackle these challenges by suggesting solutions like surface functionalization, optimizing the electrospinning process, and creating hybrid scaffolds. Our findings show that these innovations can effectively address scalability and stability issues, paving the way for broader clinical applications. This review not only emphasizes the advantages of NDs in wound healing but also introduces new insights for enhancing the biocompatibility and functionality of ND-based nanofibers, finally pushing the technology of wound dressings forward.

In-vitro and in-vivo studies of Tridax procumbens leaf extract incorporated bilayer polycaprolactone/polyvinyl alcohol-chitosan electrospun nanofiber for wound dressing application

This study was an attempt to fabricate an antibacterial wound dressing, which was a bilayered polycaprolactone / polyvinyl alcohol-chitosan (PCL/PVA-CS) nanofibrous membrane. Entrapping ethanolic leaf extract of Tridax procumbens L. (PCL/PVA-CS/Tp). The membrane was prepared using the electrospinning technique to obtain beadless uniform nanofibers. The extract was then infused into the membrane by spraying and exposing to high temperature. in vitro antibacterial activity and cell viability of the membranes were performed. An optimized concentration of 800 μg. mL-1 of Tp extract in PCL/PVA-CS/Tp evinced better antibacterial effect on E. coli than S. aureus and also showed rapid wound closure with a positive impact on the viability of L929 cell line. The tissue regeneration efficacy of PCL/PVA-CS/Tp was validated by the experiments on mice models with subcutaneous wounds created using biopsy punch and laser radiation causing burns. Furthermore, in vivo assessments illustrated that the biopsy punch wounds healed more rapidly than laser burn though healing was significant in both. The healing processes such as anti-inflammation and re-epithelialization were observed through histological study. The upregulation of proteins namely VEGF and CD31 along with a decrease in protein levels of Wnt and TGF-β indicated significant wound healing. In conclusion, the bilayered membrane infused with plant extract could be considered a potential material for wound dressing.

Antibacterial and osteogenic properties of chitosan-polyethylene glycol nanofibre-coated 3D printed scaffold with vancomycin and insulin-like growth factor-1 release for bone repair

3D printing, as a layer-by-layer manufacturing technique, enables the customization of tissue engineering scaffolds. Surface modification of biomaterials is a beneficial approach to enhance the interaction with living cells and tissues. In this research, a polylactic acid/polyethylene glycol scaffold containing 30 % bredigite nanoparticles (PLA/PEG/B) was fabricated utilizing fused deposition modeling (FDM) 3D printing. To modify the surface properties and facilitate the loading and release of therapeutics, the scaffold was coated with chitosan-polyethylene glycol (CS-PEG) nanofibers incorporating vancomycin (V) and insulin-like growth factor-1 (IGF1). The characterization was conducted using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the release of V (93.43 %) and IGF1 (95.86 %) from the fabricated scaffolds persisted for 28 days in a phosphate-buffered saline (PBS) solution. The release of V resulted in antibacterial activity against Staphylococcus aureus (S. aureus), forming an inhibition zone of 21.16 mm. Additionally, it was demonstrated that the release of IGF1 could counteract the adverse effect of V release on cell behavior, and enhance the adhesion and proliferation of MG63 cells. Preclinical in vivo studies conducted on a rat calvarial defect model validated that the bone repair was fully completed in the group treated with the fabricated scaffold within 8 weeks. Consequently, the scaffold designed in this study can serve as a versatile scaffold for achieving perfect repair of craniofacial defects.

Chitosan and ibuprofen grafted electrospun polylactic acid/gelatin membrane mitigates inflammatory response

Electrospun membranes with biomimetic fibrous structures and high specific surfaces benefit cell proliferation and tissue regeneration but are prone to cause chronic inflammation and foreign body response. To solve these problems, we herein report an approach to functionalize electrospun membranes with antibacterial and anti-inflammatory components to modulate inflammatory responses and improve implantation outcomes. Specifically, electrospun polylactic acid (PLA)/gelatin (Gel) fibers were grafted with chitosan (CS) and ibuprofen (IBU) via carbodiimide chemistry. Our results show that the surface modification strategy endows electrospun membranes with moderate antibacterial activities and sustained release of anti-inflammatory drugs. The electrospun PLA/Gel-CS-IBU membrane showed good antioxidant and anti-inflammatory activity as evidenced by suppressing M1 polarization and promoting M2 polarization of macrophagesin vitro. Similarly, it induced significantly milder chronic inflammatory responsesin vivothan unmodified electrospun membranes. Given the good anti-inflammatory and antibacterial effects, this strategy might improve the biological performance of electrospun membranes as implants in clinics.

Immunomodulation effects of collagen hydrogel encapsulating extracellular vesicles derived from calcium silicate stimulated-adipose mesenchymal stem cells for diabetic healing

Diabetic wounds are characterized by chronic inflammation, reduced angiogenesis, and insufficient collagen deposition, leading to impaired healing. Extracellular vesicles (EVs) derived from adipose-derived mesenchymal stem cells (ADSC) offer a promising cell-free therapeutic strategy, yet their efficacy and immunomodulation can be enhanced through bioactivation. In this study, we developed calcium silicate (CS)-stimulated ADSC-derived EVs (CSEV) incorporated into collagen hydrogels to create a sustained-release system for promoting diabetic wound healing. CSEV exhibited enhanced protein content, surface marker expression, and bioactive cargo enriched with pro-angiogenic and anti-inflammatory factors. In vitro, CSEV-loaded collagen significantly reduced reactive oxygen species production, promoted cell proliferation and migration compared to standard EV-loaded collagen. Cytokine profiling revealed the upregulation of anti-inflammatory cytokines and extracellular matrix components, highlighting their immunomodulatory and regenerative potential. In vivo, histological evaluation of diabetic rabbit models treated with CSEV-loaded collagen revealed superior reepithelialization and organized collagen deposition, indicating accelerated wound closure. These findings underscore the potential of CSEV-loaded collagen hydrogels as an innovative and effective therapeutic platform for enhancing diabetic wound healing by simultaneously addressing inflammation and tissue regeneration.

Mupirocin-Doped α-Cellulose Nanopaper for Wound Dressing: Development, In Vitro Characterization and Antimicrobial Studies

This research aimed to develop a mupirocin-doped α-cellulose nanopaper (MDAC-NP) as a wound dressing to accelerate wound healing while limiting localized bacterial growth. The α-cellulose nanofibrils suspension was prepared by ultrasonication followed by microfluidization and subsequently doped with 0.05% w/v mupirocin to prepare nanopaper (MDAC-NP-A). The optimized batch of MDAC-NP had a porosity of 47.46 ± 0.60%, a thickness of 30 μm and a tensile strength of 0.113 MPa. The transmission electron microscopy images revealed long, slender, intertwined nanofibrillar structures and the scanning electron microscopy confirmed stable lamellar structures with tight nanofibrillar networks, giving them translucency. MDAC-NP-A had an excellent water vapor transmission rate of 2963 ± 10.26 g/m2/day, providing an optimal moist environment locally to promote wound healing. The mupirocin inclusion in the nanopapers was corroborated by the Fourier transform infrared spectroscopy and its crystallinity by X-ray diffraction, and differential scanning calorimetry results. The 100% drug release, was observed at 12 h from optimized MDAC-NP-A with a controlled release pattern. The MDAC-NP showed better antimicrobial activity, against S. aureus (41 mm) than E. coli (25 mm) and P. aeruginosa (17 mm) and was found to be better than marketed ointment. Thus, mupirocin-doped α-cellulose nanopapers emerge as a potential wound dressing for treating primary and secondary skin infections caused by external wounds.

Natural polymer nanofiber dressings for effective management of chronic diabetic wounds: A comprehensive review

Diabetic wounds present a chronic challenge in effective treatment. Natural polymer nanofiber dressings have emerged as a promising solution due to their impressive biocompatibility, biodegradability, safety, high specific surface area, and resemblance to the extracellular matrix. These qualities make them ideal materials with excellent biological properties and cost-effectiveness. Additionally, they can effectively deliver therapeutic agents, enabling diverse treatment effects. This review offers a comprehensive overview of natural polymer-based nanofibers in diabetic wound dressings. It examines the characteristics and challenges associated with diabetic wounds and the role of natural polymers in facilitating wound healing. The review highlights the preparation, mechanism, and applications of various functional dressings composed of natural polymer nanofibers. Furthermore, it addresses the main challenges and future directions in utilizing natural polymer nanofibers for diabetic wound treatment, providing valuable insights into effective wound management for diabetic patients.

A separable double-layer self-pumping dressing containing astragaloside for promoting wound healing

Some skin wounds often have many exudate. Ordinary single layer electrospunning nanofiber wound dressings often don't have enough capacity to absorb them. Therefore, a separable double layer electrospunning nanofiber dressing was developed in this work. The dressing had a separable feature that allowed the upper layer to be separated and removed after it had absorbed a significant amount of wound exudate. This dressing consisted of an upper layer of super hydrophilic sodium polyacrylate nanofibers and a bottom layer of 3D-structure coaxial nanofibers with encapsulated Astragaloside (AS). The results showed that nanofibers had better morphology. The water absorption rate, water vapor transmission rate and free radical scavenging rate of the double-layer dressings were 1461.71 ± 39.72 %, 1193.63 ± 134 g·m-2·day-1, and 63.35 ± 3.65 %, respectively. The double-layer nanofiber dressing achieved 65.69 ± 2.62 % and 75.10 ± 6.26 % inhibition against Staphylococcus aureus and Escherichia coli, respectively. The double-layer dressing had proliferative, migratory, and adhesive effects on L929 fibroblasts. And the double-layer dressing resulted in a 96.78 ± 1.0 % wound healing rate in rats after giving a 14 days treatment. Therefore, the 3D-structure separable double-layer wound dressing designed and prepared in this study was effective in promoting wound healing.

Phytotherapeutic Hierarchical PCL-Based Scaffolds as a Multifunctional Wound Dressing: Combining 3D Printing and Electrospinning

This study focuses on developing hybrid scaffolds incorporating phytotherapeutic agents via a combination of three-dimensional (3D) printing and electrospinning to enhance mechanical properties and provide antibacterial activity, in order to address the limitations of traditional antibiotics. In this regard, 3D-printed polycaprolactone (PCL) struts are first fabricated using fused deposition modeling (FDM). Then, alkaline surface treatment is applied to improve the adhesion of electrospun nanofibers. Finally, peppermint oil (PEP) or clove oil (CLV)-incorporated PCL-gelatin (GEL) electrospun nanofibers are collected on top of the 3D-printed PCL scaffolds by electrospinning. Incorporating PEP or CLV into PCL-GEL electrospun nanofibers enhances the scaffold's layer detachment and adhesion force. In addition, the DPPH free radical scavenging activity assay indicates that incorporating PEP or CLV improves the antioxidant properties of the scaffolds. Further, antibacterial activity results reveal that PEP or CLV incorporated scaffolds exhibit inhibition against Staphylococcus aureus and Escherichia coli bacteria. Moreover, anti-inflammatory assays show that scaffolds reduce the concentration of nitric oxide (NO) released from Raw 264.7 macrophage-like cells. On the other hand, the phytotherapeutic hierarchical scaffolds have no toxic effect on normal human dermal fibroblast (NHDF) cells, and PEP or CLV enhance cell attachment and proliferation. Overall, incorporating natural phytotherapeutic agents into hierarchical scaffolds shows promise for advancing wound healing applications.

Three-dimensional printed polyelectrolyte construct containing mupirocin-loaded quaternized chitosan nanoparticles for skin repair

Despite substantial advancements in wound dressing development, effective skin repair remains a significant challenge, largely due to the persistent issue of recurrent infections. Three-dimensional printed constructs that integrate bioactive and antibacterial agents hold significant potential to address this challenge. In this study, a 3D-printed hydrogel scaffold composed of polyallylamine hydrochloride (PAH) and pectin (Pc), incorporated with mupirocin (Mp)-loaded quaternized chitosan nanoparticles (QC NPs) was fabricated. The primary objective of this study was to facilitate a controlled and sustained release of Mp via the QC NPs. The average size of QC-Mp nanoparticles was measured to be 66.05 nm and the average strand diameter and pore size of the 3D-printed construct were measured as 147.22 ± 5.83 and 388.44 ± 14.50 μm, respectively. The hemolysis rate of all scaffolds was below 2 %, indicating that they can be classified as non-hemolytic materials with sufficient blood compatibility. The PAH-Pc/QC-Mp scaffold exhibited significant antibacterial activity, enhanced cell viability in HaCat cells, sustained Mp release until day 7 (⁓60 %), and in-vivo wound healing promotion by stimulation of human keratinocytes. In conclusion, the proposed biocompatible construct demonstrates significant potential for the treatment of chronic and infected wounds by preventing infection and promoting accelerated wound healing.

Exploring nanobioceramics in wound healing as effective and economical alternatives

Wound healing is a sophisticated process for which various treatment methods have been developed. Bioceramics with the ability to release inorganic ions in biological environments play a crucial role in cellular metabolism and exhibit bactericidal activity, contributing to numerous physiological processes. Their multifaceted roles in biological systems highlight their significance. The release of different metallic ions from bioceramics enables the repair of both hard and soft tissues. These ions may be effective in cell motility, proliferation, differentiation, adhesion, angiogenesis, and antibiosis. Unlike conventional medications, the bioactivity and antibacterial properties of bioceramics are typically not associated with side effects or bacterial resistance. Bioceramics are commonly recognized for their capcity to facilitate the healing of hard tissues due to their exceptional mechanical properties. In this review, we first explore wound treatment and its prevalent methods, and subsequently, we discuss the application of three primary categories of bioceramics-oxide ceramics, silicate-based ceramics, and calcium-phosphate ceramics-in the context of wound treatment. This review introduces bioceramics as a cost-effective and efficient alternative for wound repair. Our aim is to inspire researchers to incorporate bioceramics with other biomaterials to achieve enhanced, economical, expedited, and safer wound healing.

Silver Nanoparticles in 3D Printing: A New Frontier in Wound Healing

This review examines the convergence of silver nanoparticles (AgNPs), three-dimensional (3D) printing, and wound healing, focusing on significant advancements in these fields. We explore the unique properties of AgNPs, notably their strong antibacterial efficacy and their potential applications in enhancing wound recovery. Furthermore, the review delves into 3D printing technology, discussing its core principles, various materials employed, and recent innovations. The integration of AgNPs into 3D-printed structures for regenerative medicine is analyzed, emphasizing the benefits of this combined approach and identifying the challenges that must be addressed. This comprehensive overview aims to elucidate the current state of the field and to direct future research toward developing more effective solutions for wound healing.

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.

Tunicate cellulose nanocrystal reinforced multifunctional hydrogel with super flexible, fatigue resistant, antifouling and self-adhesive capability for effective wound healing

Hydrogels as skin wound dressings have been extensively studied owing to their good flexibility and biocompatibility. Nevertheless, the mechanical performance, adhesive capability, antifouling and antibacterial properties of conventional hydrogels are still unsatisfactory, which hinder the application of hydrogel for cutaneous healing. Here, we developed a novel biocompatible multifunctional hydrogel with super flexible, fatigue resistant, antifouling and self-adhesive capability for effective wound healing, where naturally rigid polymers including quaternized chitosan (QCS) and Tunicate cellulose nanocrystals (TCNCs) are used as bioactive cross-linkers and reinforcers to endow the hydrogel with excellent mechanical and antibacterial property, and the synergistic contributions from the poly(acrylic acid/methacrylate anhydride dopamine/sulfobetaine methacrylate) (poly(AA/DMA/SBMA)) chains and QCS endow the hydrogel with excellent adhesive property, antioxidant, antifouling and pH-responsive sustained drug release capabilities. The optimized hydrogel exhibited high tensile strength (77.69 KPa), large tensile strain (889.9 %), large toughness (307.51KJ.m-3), high adhesive strength (35.57 KPa) and ideal compressive property. The in vivo infected full-thickness skin model demonstrated that the hydrogel with vanvomycin sustained release ability efficiently improved the granulation tissue formation, facilitating collagen deposition and reducing inflammatory expression, thus effectively accelerating wound healing. This superiorly skin-adhesive antibacterial biocompatible hydrogel appears to be a promising candidate for wound therapy.

Advances in Electrospun Nanofiber Membranes for Dermatological Applications: A Review

In recent years, a wide variety of high-performance and versatile nanofiber membranes have been successfully created using different electrospinning methods. As vehicles for medication, they have been receiving more attention because of their exceptional antibacterial characteristics and ability to heal wounds, resulting in improved drug delivery and release. This quality makes them an appealing choice for treating various skin conditions like wounds, fungal infections, skin discoloration disorders, dermatitis, and skin cancer. This article offers comprehensive information on the electrospinning procedure, the categorization of nanofiber membranes, and their use in dermatology. Additionally, it delves into successful case studies, showcasing the utilization of nanofiber membranes in the field of skin diseases to promote their substantial advancement.

Endogenous electric field coupling Mxene sponge for diabetic wound management: haemostatic, antibacterial, and healing

Improper management of diabetic wound effusion and disruption of the endogenous electric field can lead to passive healing of damaged tissue, affecting the process of tissue cascade repair. This study developed an extracellular matrix sponge scaffold (K1P6@Mxene) by incorporating Mxene into an acellular dermal stroma-hydroxypropyl chitosan interpenetrating network structure. This scaffold is designed to couple with the endogenous electric field and promote precise tissue remodelling in diabetic wounds. The fibrous structure of the sponge closely resembles that of a natural extracellular matrix, providing a conducive microenvironment for cells to adhere grow, and exchange oxygen. Additionally, the inclusion of Mxene enhances antibacterial activity(98.89%) and electrical conductivity within the scaffold. Simultaneously, K1P6@Mxene exhibits excellent water absorption (39 times) and porosity (91%). It actively interacts with the endogenous electric field to guide cell migration and growth on the wound surface upon absorbing wound exudate. In in vivo experiments, the K1P6@Mxene sponge reduced the inflammatory response in diabetic wounds, increased collagen deposition and arrangement, promoted microvascular regeneration, Facilitate expedited re-epithelialization of wounds, minimize scar formation, and accelerate the healing process of diabetic wounds by 7 days. Therefore, this extracellular matrix sponge scaffold, combined with an endogenous electric field, presents an appealing approach for the comprehensive repair of diabetic wounds.

Exploring the Potentials of Chitin and Chitosan-Based Bioinks for 3D-Printing of Flexible Electronics: The Future of Sustainable Bioelectronics

Chitin and chitosan-based bioink for 3D-printed flexible electronics have tremendous potential for innovation in healthcare, agriculture, the environment, and industry. This biomaterial is suitable for 3D printing because it is highly stretchable, super-flexible, affordable, ultrathin, and lightweight. Owing to its ease of use, on-demand manufacturing, accurate and regulated deposition, and versatility with flexible and soft functional materials, 3D printing has revolutionized free-form construction and end-user customization. This study examined the potential of employing chitin and chitosan-based bioinks to build 3D-printed flexible electronic devices and optimize bioink formulation, printing parameters, and postprocessing processes to improve mechanical and electrical properties. The exploration of 3D-printed chitin and chitosan-based flexible bioelectronics will open new avenues for new flexible materials for numerous industrial applications.

A unidirectional water-transport antibacterial bilayer nanofibrous dressing based on chitosan for accelerating wound healing

Excessive accumulation of exudate from wounds often causes infection and hinders skin regeneration. To handle wound exudate quickly and prevent infection, we developed an antibacterial Janus nanofibrous dressing with a unidirectional water-transport function. The dressing consists of a hydrophilic chitosan aerogel (CS-A) as the outer layer and a hydrophobic laurylated chitosan (La-CS) nanofibrous membrane as the inner layer. These dressings achieved excellent liquid absorption performance (2987.8 ± 123.5 %), air and moisture permeability (997.8 ± 23.1 g/m2/day) and mechanical strength (5.1 ± 2.6 MPa). This performance was obtained by adjusting the density of CS-A and the thickness of the La-CS membrane. Moreover, the dressing did not induce significant toxicity to cells and can prevent bacterial aggregation and infection at the wound site. Animal experiments showed that the dressing can shorten the inflammatory phase, enhance blood vessel generation, and accelerate collagen deposition, thus promoting wound healing. Overall, these results suggest that this Janus dressing is a promising material for clinical wound care.

A comprehensive review on recent progress in chitosan composite gels for biomedical uses

Chitosan (CS) composite gels have emerged as promising materials with diverse applications in biomedicine. This review provides a concise overview of recent advancements and key aspects in the development of CS composite gels. The unique properties of CS, such as biocompatibility, biodegradability, and antimicrobial activity, make it an attractive candidate for gel-based composites. Incorporating various additives, such as nanoparticles, polymers, and bioactive compounds, enhances the mechanical, thermal, and biological and other functional properties of CS gels. This review discusses the fabrication methods employed for CS composite gels, including blending and crosslinking, highlighting their influence on the final properties of the gels. Furthermore, the uses of CS composite gels in tissue engineering, wound healing, drug delivery, and 3D printing highlight their potential to overcome a number of the present issues with drug delivery. The biocompatibility, antimicrobial properties, electroactive, thermosensitive and pH responsive behavior and controlled release capabilities of these gels make them particularly suitable for biomedical applications. In conclusion, CS composite gels represent a versatile class of materials with significant potential for a wide range of applications. Further research and development efforts are necessary to optimize their properties and expand their utility in pharmaceutical and biomedical fields.

Biomimetic tri-layered artificial skin comprising silica gel-collagen membrane-collagen porous scaffold for enhanced full-thickness wound healing

Full-thickness wounds are severe cutaneous damages with destroyed self-healing function, which need efficient clinical interventions. Inspired by the hierarchical structure of natural skin, we have for the first time developed a biomimetic tri-layered artificial skin (TLAS) comprising silica gel-collagen membrane-collagen porous scaffold for enhanced full-thickness wound healing. The TLAS with the thickness of 3-7 mm displays a hierarchical nanostructure consisting of the top homogeneous silica gel film, the middle compact collagen membrane, and the bottom porous collagen scaffold, exquisitely mimicking the epidermis, basement membrane and dermis of natural skin, respectively. The 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide/N-Hydroxysuccinimide-dehydrothermal (EDC/NHS-DHT) dual-crosslinked collagen composite bilayer, with a crosslinking degree of 79.5 %, displays remarkable biocompatibility, bioactivity, and biosafety with no risk of hemolysis and pyrogen reactions. Notably, the extra collagen membrane layer provides a robust barrier to block the penetration of silica gel into the collagen porous scaffold, leading to the TLAS with enhanced biocompatibility and bioactivity. The full-thickness wound rat model studies have indicated the TLAS significantly facilitates the regeneration of full-thickness defects by accelerating re-epithelization, collagen deposition and migration of skin appendages. The highly biocompatible and bioactive tri-layered artificial skin provides an improved treatment for full-thickness wounds, which has great potential in tissue engineering.

Chitosan-based materials for dental implantology: A comprehensive review

Chitosan, a versatile biopolymer, has gained recognition in the discipline of dental implantology due to possessing salient properties. This comprehensive review explores the potential of chitosan in dental implants, focusing on its biocompatibility, bioactivity, and the various chitosan-based materials that have been utilized for dental implant therapy. The review also highlights the importance of surface treatment in dental implants to enhance osseointegration and inhibit bacterial biofilm formation. Additionally, the chemical structure, properties, and sources of chitosan are described, along with its different structural forms. The characteristics of chitosan particularly color, molecular weight, viscosity, and degree of deacetylation are discussed about their influence on its applications. This review provides valuable insights into the promising utilization of polymeric chitosan in enhancing the success and functionality of dental implants. This study highlights the potential applications of chitosan in oral implantology. Chitosan possesses various advantageous properties, including muco-adhesiveness, hemostatic action, biocompatibility, biodegradability, bioactivity, and antibacterial and antifungal activities, which enhance its uses in dental implantology. However, it has limited aqueous solubility at the physiological pH, which sometimes restricts its biological application, but this problem can be overcome by using modified chitosan or chitosan derivatives, which have also shown encouraging results. Recent research suggests that chitosan may act as a promising material for coating titanium-based implants, improving osteointegration together with antibacterial properties.

Platelet rich fibrin and simvastatin-loaded pectin-based 3D printed-electrospun bilayer scaffold for skin tissue regeneration

Designing multifunctional wound dressings is a prerequisite to prevent infection and stimulate healing. In this study, a bilayer scaffold (BS) with a top layer (TL) comprising 3D printed pectin/polyacrylic acid/platelet rich fibrin hydrogel (Pec/PAA/PRF) and a bottom nanofibrous layer (NL) containing Pec/PAA/simvastatin (SIM) was produced. The biodegradable and biocompatible polymers Pec and PAA were cross-linked to form hydrogels via Ca2+ activation through galacturonate linkage and chelation, respectively. PRF as an autologous growth factor (GF) source and SIM together augmented angiogenesis and neovascularization. Because of 3D printing, the BS possessed a uniform distribution of PRF in TL and an average fiber diameter of 96.71 ± 18.14 nm was obtained in NL. The Young's modulus of BS was recorded as 6.02 ± 0.31 MPa and its elongation at break was measured as 30.16 ± 2.70 %. The wound dressing gradually released growth factors over 7 days of investigation. Furthermore, the BS significantly outperformed other groups in increasing cell viability and in vivo wound closure rate (95.80 ± 3.47 % after 14 days). Wounds covered with BS healed faster with more collagen deposition and re-epithelialization. The results demonstrate that the BS can be a potential remedy for skin tissue regeneration.

Core-shell nanofibers containing L-arginine stimulates angiogenesis and full thickness dermal wound repair

Despite the advances in medicine, wound healing is still challenging and piques the interest of biomedical engineers to design effective wound dressings using natural and artificial polymers. In present study, coaxial electrospinning was employed to fabricate core-shell nanofiber-based wound dressing, with core composed of polyacrylamide (PAAm) and shell comprising 0.5 % solution of L-Arginine (L-Arg) in aloe vera and keratin (AloKr). Aloe vera and keratin were added as natural polymers to promote angiogenesis, reduce inflammation, and provide antibacterial activity, whereas PAAm in core was used to improve the tensile properties of the wound dressing. Moreover, L-Arg was incorporated in shell to promote angiogenesis and collagen synthesis. The fiber diameter of PAAm/(AloKr/L-Arg) core-shell fibers was (93.33 ± 35.11 nm) with finer and straighter fibers and higher water holding capacity due to increased surface area to volume ratio. In terms of tensile properties, the PAAm/(AloKr/L-Arg) core-shell nanofibers with tensile strength and elastic modulus of 2.84 ± 0.27 MPa and 62.15 ± 5.32 MPa, respectively, showed the best mechanical performance compared to other nanofibers tested. Furthermore, PAAm/(AloKr/L-Arg) exhibited the highest L-Arg release (87.62 ± 3.02 %) and viability of L929 cells in vitro compared to other groups. In addition, the highest rate of in vivo full thickness wound healing was observed in PAAm/(AloKr/L-Arg) group compared to other groups. It significantly enhanced the angiogenesis, neovascularization, and cell proliferation. The prepared PAAm/(AloKr/L-Arg) core-shell nanofibrous dressing could be promising for full-thickness wound healing.

Hydrogel Based on Riclin Cross-Linked with Polyethylene Glycol Diglycidyl Ether as a Soft Filler for Tissue Engineering

Hydrogels composed of natural polysaccharides have been widely used as filling materials, with a growing interest in medical cosmetology and skin care. However, conventional commercial dermal fillers still have limitations, particularly in terms of mechanical performance and durability in vivo. In this study, a novel injectable and implantable hydrogel with adjustable characteristics was prepared from succinoglycan riclin by introducing PEG diglycidyl ether as a cross-linker. FTIR spectra confirmed the cross-linking reaction. The riclin hydrogels exhibited shear-thinning behavior, excellent mechanical properties, and cytocompatibility through in vitro experiments. Furthermore, when compared with subcutaneous injection of a commercial hyaluronic acid hydrogel, the riclin hydrogels showed enhanced persistence and biocompatibility in Balb/c mice after 16 weeks. These results demonstrate the great potential of the riclin-based hydrogel as an alternative to conventional commercial soft tissue fillers.

3D printed polylactic acid-based nanocomposite scaffold stuffed with microporous simvastatin-loaded polyelectrolyte for craniofacial reconstruction

Critical sized craniofacial defects are among the most challenging bone defects to repair, due to the anatomical complexity and aesthetic importance. In this study, a polylactic acid/hardystonite-graphene oxide (PLA/HTGO) scaffold was fabricated through 3D printing. In order to upgrade the 3D printed scaffold to a highly porous scaffold, its channels were filled with pectin-quaternized chitosan (Pec-QCs) polyelectrolyte solution containing 0 or 20 mg/mL of simvastatin (Sim) and then freeze-dried. These scaffolds were named FD and FD-Sim, respectively. Also, similar PLA/HTGO scaffolds were prepared and dip coated with Pec-QCs solution containing 0 or 20 mg/mL of Sim and were named DC and DC-Sim, respectively. The formation of macro/microporous structure was confirmed by morphological investigations. The release of Sim from DC-Sim and FD-Sim scaffolds after 28 days was measured as 77.40 ± 5.25 and 86.02 ± 3.63 %, respectively. Cytocompatibility assessments showed that MG-63 cells had the highest proliferation, attachment and spread on the Sim containing scaffolds, especially FD-Sim. In vivo studies on a rat calvarial defect model revealed that an almost complete recovery occurred in the group treated with FD-Sim scaffold after 8 weeks and the defect was filled with newly formed bone. The results of this study acknowledge that the FD-Sim scaffold can be a perfect candidate for calvarial defect repair.

A double-layer cellulose/pectin-soy protein isolate-pomegranate peel extract micro/nanofiber dressing for acceleration of wound healing

Multi-layered wound dressings can closely mimic the hierarchical structure of the skin. Herein, a double-layer dressing material is fabricated through electrospinning, comprised of a nanofibrous structure as a healing-support layer or the bottom layer (BL) containing pectin (Pec), soy protein isolate (SPI), pomegranate peel extract (P), and a cellulose (Cel) microfiber layer as a protective/monitoring layer or top layer (TL). The formation of a fine bilayer structure was confirmed using scanning electron microscopy. Cel/Pec-SPI-P dressing showed a 60.05 % weight loss during 7 days of immersion in phosphate buffered solution. The ultimate tensile strength, elastic modulus, and elongation at break for different dressings were within the range of 3.14-3.57 MPa, 32.26-36.58 MPa, and 59.04-63.19 %, respectively. The release of SPI and phenolic compounds from dressings were measured and their antibacterial activity was evaluated. The fabricated dressing was non-cytotoxic following exposure to human keratinocyte cells. The Cel/Pec-SPI-P dressing exhibited excellent cell adhesion and migration as well as angiogenesis. More importantly, in vivo experiments on Cel/Pec-SPI-P dressings showed faster epidermal layer formation, blood vessel generation, collagen deposition, and a faster wound healing rate. Overall, it is anticipated that the Cel/Pec-SPI-P bilayer dressing facilitates wound treatment and can be a promising approach for clinical use.