Nanofibers reinforced injectable hydrogel with self-healing, antibacterial, and hemostatic properties for chronic wound healing

Mussel-Inspired MXene/Antimicrobial Peptide-Integrated Photosensitive Poly(vinyl alcohol)-Based Hydrogel with Antibacterial, Anti-Inflammatory, and Electroactive Properties for Accelerated Wound Healing

Backgrounds: The buildup of reactive oxygen species (ROS) in infected wounds triggers an excessive inflammatory response, while the overuse of antibiotics has contributed to increased bacterial resistance. Therefore, developing wound dressings that effectively eliminate ROS and inhibit bacterial growth is crucial. Methods: Inspired by mussel-derived proteins, we developed a polydopamine (PDA)-grafted MXene (PDA@MXene) and 3,4-dihydroxyphenylalanine-PonG1 (DOPA-PonG1)-modified photosensitive poly(vinyl alcohol) (PVA) hydrogel as a wound dressing. PDA@MXene was synthesized through dopamine self-polymerization on the MXene surface, while tyrosine hydroxylation was used to introduce DOPA into the antibacterial peptide ponericin G1 (PonG1). The hydrogel and its components were characterized, and their morphology was examined. The hydrogel's hemostatic ability, mechanical properties, and conductivity were evaluated. In vitro studies systematically evaluated antioxidative effects, antibacterial activity, biocompatibility, and expression of tissue regeneration-related factors. An infected full-thickness skin defect model was established in vivo, and different hydrogel treatments were applied. The wound-healing rate was then measured, followed by histological analysis using hematoxylin and eosin, Masson, Sirius Red, and immunofluorescence staining to investigate the healing mechanism. Results: The DOPA sequence enhanced PonG1 stability on the hydrogel surface, leading to sustained antibacterial ability. PDA@MXene significantly improved the hydrogel's conductivity and mechanical strength. Notably, the combined effects of DOPA-PonG1 and PDA@MXene contributed to enhanced antibacterial and ROS-scavenging properties. In vivo findings demonstrated that the DOPA-PonG1/PDA@MXene/PVA hydrogel accelerated infected wound healing by promoting angiogenesis and collagen deposition while reducing excessive inflammation. This study presents an innovative approach for treating infected wound defects and holds promise for clinical applications.

Multi-crosslinking nanoclay/oxidized cellulose hydrogel bandage with robust mechanical strength, antibacterial and adhesive properties for emergency hemostasis

Emergency bleeding presents significant challenges such as high blood flow and rapid hemorrhaging. However, many existing hemostatic bandages face limitations, including the uncontrolled release of hemostatic agents, insufficient mechanical strength, poor adhesion, and complex manufacturing processes. To address these limitations, we developed a multifunctional hydrogel bandage for emergency hemostasis using a one-pot synthesis method. The hydrogel was composed of kaolin, N-hydroxysuccinimide-grafted oxidized microcrystalline cellulose (OMCC-NHS), and polyacrylic acid (PAA). Featuring a multi-crosslinked network, it exhibited favorable elasticity (∼942 %), tensile strength (∼220 kPa), fatigue resistance, and robust tissue adhesion (∼55 kPa)-3.9 times stronger than commercial wound-closure strips, and it maintained adhesion even underwater. In addition to its mechanical properties, the hydrogel also exhibited satisfactory antibacterial activity, cytocompatibility, and histocompatibility. In vivo evaluations revealed an impressive hemostatic performance in rat models of liver bleeding, femoral artery bleeding, and tail amputation. Specifically, in the liver bleeding model, the hydrogel reduced blood loss to only 0.1 g, which is just 32 % of the blood loss seen with medical gauze. Notably, in New Zealand rabbit models with cardiac punctures and liver injuries, the hydrogel achieved rapid hemostasis and stopped the bleeding within seconds. The effective hemostatic ability of this hydrogel is primarily due to its ability to facilitate multistep hemostasis, which includes sealing the wound, rapidly absorbing blood, promoting RBC and platelets adhesion, and activating the intrinsic coagulation cascade. Therefore, this study provides a promising approach for developing gel-based hemostatic bandages, specifically tailored for emergency compressible bleeding scenarios.

Green biosynthetic silver nanoparticles from Ageratum conyzoides as multifunctional hemostatic agents: Combining hemostasis, antibacterial, and anti-inflammatory properties for effective wound healing

Widespread interest in new hemostatic agents arises from the challenge of simultaneously satisfying the requirements of hemostatic, antibacterial, and anti-inflammatory properties while also considering the associated economic costs. An ideal hemostasis material should facilitate rapid hemostasis, intervene against infection, promote wound healing, and be cost-effective and easy to prepare. Herein, we demonstrate that medicinal plant-derived silver nanoparticles (AgNPs) exhibit the potential to constitute a promising multifunctional hemostatic reagent library. Biogenic synthesis of AgNPs utilizing Ageratum conyzoides extracts, referred to as AC-AgNPs, successfully combines the hemostatic and anti-inflammatory properties of Ageratum conyzoides with the inherent antibacterial activity exhibited by AgNPs. In-vitro coagulation experiments indicate that AC-AgNPs have a strong hemostatic effect, which is related to their size, concentration, and negative charge, and they exhibit low cytotoxicity and hemolysis. Subsequent experiments including scanning electron microscopy, flow cytometry, western blotting, and network pharmacology analysis have revealed that AC-AgNPs can cause platelet activation and aggregation, stimulated kallikrein-kinin system, shorten activated partial thromboplastin and prothrombin time, and increase fibrinogen content. These findings indicate that AC-AgNPs act on multiple signaling pathways, including endogenous and exogenous coagulation pathways, complement system, platelet activation, and aggregation. Furthermore, the hemostatic efficacy of AC-AgNPs is demonstrated in mouse models of tail amputation and liver injury, where AC-AgNPs significantly reduce the amount of blood loss and the bleeding time. Our work shows that AC-AgNPs possess strong hemostatic, anti-inflammatory, and antibacterial capabilities, ultimately facilitating wound healing. The biogenic synthesis of AgNPs from medicinal plants could be a multifunctional hemostatic candidate for practical application.

Multifunctional hydrogels for the healing of oral ulcers

Oral ulcers are one of the most common oral diseases in clinical practice. Its etiology is complex and varied. Due to the dynamic nature of the oral environment, the wound surface is painful due to contact and wear, which seriously affects the quality of life of patients. Oral ulcers are often treated with topical drug therapy. Studies have shown that functional hydrogels play a positive role in promoting wound healing, showing unique advantages in wound dressings. In this paper, the causes and healing characteristics of oral ulcers are discussed in depth, and then the common treatment methods for oral ulcers are summarized and compared. Finally, the potential of functional hydrogels in the treatment of oral ulcers is discussed and projected through a review of the literature in recent years.

Double-alternating injectable multifunctional hydrogel based on chitosan for skin wound repair

Injectable hydrogels can be suitable for any irregular wounds to play an important role in wound healing, which have attracted much attention from researchers. Here, a chitosan-based double alternating injectable hydrogel had been proposed, which aligned with characteristics of wound healing. First of all, carboxymethyl chitosan (CMCS) and oxidized gellant (OGG) were used to fabricate above double-alternating injectable hydrogel skeleton (COG) through Schiff base bond. Then, dipotassium glycyrrhizinate (DPG) and bioactive glass (BG) were loaded respectively into COG, forming COG2-D10 and COG2-B0.5 hydrogel. Various properties of above hydrogels such as rheological behaviors, injectable capability, cytocompatibility, antibacterial and anti-inflammatory activity were systematically investigated. The results indicated that above hydrogel not only had a stable network structure, good toughness, injectability, and excellent adhesive properties, but also exhibited efficient antibacterial, anti-inflammatory, hemostatic, and biocompatible properties. The investigation of in vivo full-thickness skin wound healing showed that compared with COG2-D10 or COG2-B0.5 hydrogel alone, the double-alternating COG2-D10/COG2-B0.5 hydrogel could better enhance the efficacy of drugs, promote cell migration and proliferation, accelerate collagen fiber deposition and neovascularization, and significantly improve wound healing (p < 0.01). Therefore, the double-alternating therapy strategy of hydrogel will provide a new approach for the clinical treatment of skin wound healing.

Application of Drug Delivery System Based on Nanozyme Cascade Technology in Chronic Wound

Chronic wounds are characterized by long-term inflammation, including diabetic ulcers, traumatic ulcers, etc., which provide an optimal environment for bacterial proliferation. At present, antibiotics are the main clinical treatment method for chronic wound infections. However, the overuse of antibiotics may accelerate the emergence of drug-resistant bacteria, which poses a significant threat to human health. Therefore, there is an urgent need to develop new therapeutic strategies for bacterial infections. Nanozyme-based antimicrobial therapy (NABT) is an emerging antimicrobial strategy with broad-spectrum activity and low drug resistance compared to traditional antibiotics. NABT has shown great potential as an emerging antimicrobial strategy by catalyzing the generation of reactive oxygen species (ROS) with its enzyme-like catalytic properties, producing a powerful bactericidal effect without developing drug resistance. Nanozyme-based cascade antimicrobial technology offers a new approach to infection control, effectively improving antimicrobial efficacy by activating cascades against bacterial cell membranes and intracellular DNA while minimizing potential side effects. However, it is worth noting that this technology is still in the early stages of research. This article comprehensively reviews wound classification, current methods for the treatment of wound infection, different types of nanozymes, the application of nanozyme cascade reaction technology in antimicrobial therapy, and future challenges and prospects.

Zeolitic imidazolate framework-8@polydopamine decorated carboxylated chitosan hydrogel with photocatalytic and photothermal antibacterial activity for infected wound healing

Open wounds are susceptible to bacterial infections, and antibiotics are commonly used to treat these infections. However, widespread use of antibiotics will easily induce bacterial resistance. Green antibacterial agents serve as excellent alternative for antibiotics in infection therapy. In this work, polydopamine (PDA) was used to modify the surface of ZIF-8, which not only enhances the water stability of Zeolitic imidazolate framework-8(ZIF-8) but also improves its photocatalytic and photothermal capabilities. ZIF-8@PDA was incorporated into carboxylated chitosan (CCS) films as an antibacterial agent, the resulting ZIF-8@PDA-CCS films exhibit excellent ionic/photocatalytic/photothermal antibacterial performance. The film exhibited an impressive 99% in vitro bacterial inhibition rate. After treatment with ZIF-8@PDA-CCS, the bacteria in infected wounds can be completely suppressed. These findings suggest that ZIF-8@PDA-CCS could serve as a potentional antibacterial dressing.

NIR-II Image-Guided Wound Healing in Hypoxic Diabetic Foot Ulcers: The Potential of Ergothioneine-Luteolin-Chitin Hydrogels

Hypoxic diabetic foot ulcers (HDFUs) pose a challenging chronic condition characterized by oxidative stress damage, bacterial infection, and persistent inflammation. This study introduces a novel therapeutic approach combining ergothioneine (EGT), luteolin (LUT), and quaternized chitosan oxidized dextran (QCOD) to address these challenges and facilitate wound healing in hypoxic DFUs. In vitro, assessments have validated the biosafety, antioxidant, and antimicrobial properties of the ergothioneine-luteolin-chitin (QCOD@EGT-LUT) hydrogel. Furthermore, near-infrared II (NIR-II) fluorescence image-guided the application of QCOD@EGT-LUT hydrogel in simulated HDFUs. Mechanistically, QCOD@EGT-LUT hydrogel modulates the diabetic wound microenvironment by reducing reactive oxygen species (ROS). In vivo studies demonstrated increased expression of angiogenic factors mannose receptor (CD206) and latelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), coupled with decreased inflammatory factors tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), thereby promoting diabetic wound healing through up-regulation of transforming growth factor β-1 (TGF-β1).

GelMA hydrogels reinforced by PCL@GelMA nanofibers and bioactive glass induce bone regeneration in critical size cranial defects

BACKGROUND

The process of bone healing is complex and involves the participation of osteogenic stem cells, extracellular matrix, and angiogenesis. The advancement of bone regeneration materials provides a promising opportunity to tackle bone defects. This study introduces a composite hydrogel that can be injected and cured using UV light.

RESULTS

Hydrogels comprise bioactive glass (BG) and PCL@GelMA coaxial nanofibers. The addition of BG and PCL@GelMA coaxial nanofibers improves the hydrogel's mechanical capabilities (353.22 ± 36.13 kPa) and stability while decreasing its swelling (258.78 ± 17.56%) and hydration (72.07 ± 1.44%) characteristics. This hydrogel composite demonstrates exceptional biocompatibility and angiogenesis, enhances osteogenic development in bone marrow mesenchymal stem cells (BMSCs), and dramatically increases the expression of critical osteogenic markers such as ALP, RUNX2, and OPN. The composite hydrogel significantly improves bone regeneration (25.08 ± 1.08%) in non-healing calvaria defects and promotes the increased expression of both osteogenic marker (OPN) and angiogenic marker (CD31) in vivo. The expression of OPN and CD31 in the composite hydrogel was up to 5 and 1.87 times higher than that of the control group at 12 weeks.

CONCLUSION

We successfully prepared a novel injectable composite hydrogel, and the design of the composite hydrogels shows significant potential for enhancing biocompatibility, angiogenesis, and improving osteogenic and angiogenic marker expression, and has a beneficial effect on producing an optimal microenvironment that promotes bone repair.

Spatially controllable fluid hydrogel with in-situ electrospinning PCL/chitosan fiber for treating irregular wounds

Skin injuries sustained during exercise are often irregular in shape and frequently accompanied by infections. Bacteria residing in the crevices of these wounds can lead to persistent infections. Routine wound monitoring, which requires removing the wound dressing to assess recovery, is inconvenient and increases the risk of infection. To address this, we prepared a polyvinyl alcohol/polyhydroxylated fullerenes ((PVA/PHF) hydrogel with good fluidity and photothermal antibacterial properties, which can penetrate into the crevices of irregular wounds. After the hydrogel was applied to the wound, the hydrogel was locally defined by the polycaprolactone/Chitosan (PCL/CS) membrane of in-situ electrospinning, which effectively killed bacteria, and the healing efficiency was increased by 240 % in the wound healing experiment. The PVA/PHF hydrogel exhibits excellent electrical conductivity, making it suitable for real-time monitoring of human body motion as a strain sensor. This capability provides doctors with an accurate basis for wound assessment. At the same time, the hydrogel can achieve self-healing within 1.5 s and withstand up to 2200 % tensile strain, which can be used for large-scale motion monitoring of the human body. This flowable hydrogel, capable of penetrating wound crevices, offers a dual function of both treatment and monitoring.

Polyhedrin microcrystals embedded with bFGF promote wound healing

Growth factors play a critical role in wound healing, and finding a suitable biosustained-release system has always been a research hotspot. Bombyx mori cypovirus (BmCPV) is an insect virus, which produces polyhedra that encapsulate progeny virions. In this study, we found that the viral structural protein VP7 encoded by the BmCPV genomic dsRNAs S7 segment can interact with polyhedrin (Polh) encoded by the BmCPV genomic dsRNAs S10 segment. We also confirmed that the amino acid sequence at position 331-360 (VP7-tag) of VP7 is needed to interact with Polh. We found that VP7-tag can be used as an immobilization signal to direct the incorporation of foreign proteins into polyhedra. Furthermore, we constructed polyhedra (bFGF-polyhedra) containing basic fibroblast growth factor (bFGF) using a baculovirus expression system co-expressing Polh and bFGF-VP7 (fusion of VP7-tag to C-terminus of bFGF). We found that bFGF-VP7 embedded into polyhedra was difficult to degrade in the natural environment, and bFGF-VP7 was continuously released from the polyhedra, enhancing cell proliferation and migration. The animal model was used to assess the effect of bFGF-polyhedra spray on the healing of full-thickness wounds. bFGF-polyhedra promoted the expression of TGF-β1, α-SMA, and PCNA, inhibited the expression of proinflammatory factors NF-κB and COX-2, promoted the proliferation and differentiation of fibroblasts, enhanced collagen production and epidermal regeneration, and improved wound healing. These results indicated that bFGF-polyhedra has a promising potential for accelerating wound healing.

Multifunctional Nanofiber Membranes Constructed by Microfluidic Blow-Spinning to Inhibit Scar Formation at Early Intervention Stage

Pathological scarring has been a challenge in skin injury repair since ancient times, and prophylactic treatment in the early stages of wound healing usually results in delayed wound healing. In this study, poly(ethylene oxide) (PEO) and chitosan (CTS) were used as carrier materials to construct multifunctional pirfenidone (PFD)/CTS/PEO (PCP) nanofiber membranes (NFMs) loaded with PFD by microfluidic blow-spinning (MBS). MBS is a good method for quickly, safely, and greenly constructing large-area manufacturing of inexpensive NFMs. PCP NFMs were uniform in external morphology, with diameters ranging from 200 to 500 nm. The encapsulation efficiency of the drug-loaded PCP NFMs was above 80%, which had a good slow release, visualization, water absorption, and biocompatibility. The inhibitory effect of PCP NFMs on normal human dermal fibroblasts was dose-dependent and inhibited the expression of the transforming growth factor-β1/SMAD family member 3 (TGF-β1/SMAD3) signaling pathway. PCP NFMs showed significant antibacterial effects against both Staphylococcus aureus and Escherichia coli. In the rabbit ear scar experiment, the wound healed about 70% on day 5 and almost completely on day 10 after PCP-3 NFMs treatment, with the thinnest scar tissue, skin color, tenderness close to normal tissue, and a Vancouver scar scale score of less than 5. PCP-3 NFMs had good effects on anti-inflammatory, wound healing, and collagen-I deposition reducing effects. In conclusion, PCP-3 NFMs can both promote wound healing and intervene to inhibit pathological scarring in advance, making them a potential multifunctional wound dressing for early prevention and treatment of pathological scarring.

Polysaccharide- and protein-based hydrogel dressings that enhance wound healing: A review

Hydrogels can possess desired biochemical and mechanical properties, excellent biocompatibility, satisfactory biodegradability, and biological capabilities that promote skin repair, making them ideal candidates for skin healing dressings. Polysaccharides, such as chitosan, hyaluronic acid and sodium alginate as well as proteins, including gelatin, collagen and fibroin proteins, are biological macromolecules celebrated for their biocompatibility and biodegradability, are at the forefront of innovative hydrogel dressing development. This work first summarizes the skin wound healing process and its influencing factors, and then systematically articulates the multifunctional roles of hydrogels based on biological macromolecules (polysaccharides and proteins) as dressing in addressing bacterial infection, hemorrhage and inflammation during wound healing. Furthermore, this review explores the potential of these hydrogels as vehicles for combination therapy, by incorporating growth factors or stem cells. Finally, the article offers insights into future directions of such hydrogels in wound repair field.

A Descriptive Review on the Potential Use of Diatom Biosilica as a Powerful Functional Biomaterial: A Natural Drug Delivery System

Although various chemically synthesized materials are essential in medicine, food, and agriculture, they can exert unexpected side effects on the environment and human health by releasing certain toxic chemicals. Therefore, eco-friendly and biocompatible biomaterials based on natural resources are being actively explored. Recently, biosilica derived from diatoms has attracted attention in various biomedical fields, including drug delivery systems (DDS), due to its uniform porous nano-pattern, hierarchical structure, and abundant silanol functional groups. Importantly, the structural characteristics of diatom biosilica improve the solubility of poorly soluble substances and enable sustained release of loaded drugs. Additionally, diatom biosilica predominantly comprises SiO2, has high biocompatibility, and can easily hybridize with other DDS platforms, including hydrogels and cationic DDS, owing to its strong negative charge and abundant silanol groups. This review explores the potential applications of various diatom biosilica-based DDS in various biomedical fields, with a particular focus on hybrid DDS utilizing them.

Sprayable, thermosensitive hydrogels for promoting wound healing based on hollow, porous and pH-sensitive ZnO microspheres

A solvothermal method and the subsequent heat treatment process were developed to fabricate hollow ZnO particles with hierarchical pores on a large scale. The as-obtained hollow, porous ZnO microspheres with tunable sizes, high specific surface areas, pH sensitivity, antibacterial properties, and high adsorption capacities showed significant advantages for drug delivery. Sprayable hydrogels containing hollow, porous ZnO microspheres and curcumin nanoparticles (CNPs) were prepared to accelerate wound healing. The water-dispersed CNPs promoted both the migration of fibroblasts and angiogenesis and an aqueous solution of Pluronic F127 (a temperature-sensitive phase-change hydrogel material) was shown to be an effective choice for medical dressings. The experimental data suggest that hollow, porous ZnO microspheres can be loaded with additional CNPs to achieve continuous long-term therapeutic effects.

Silk fibroin biohydrogel composites for loading and ordered release of multiple active ingredients with enhanced bioactivity

Bioactive hydrogels are currently receiving significant attention. In this study, silk fibroin tyramine-modified gelatin hydrogels (SF-TG) with varying degrees of tyramine root substitution were explored. The physicochemical property and biocompatibility of low degree of substitution tyramine-modified gelatin hydrogel (SF-LTG) and high degree of substitution tyramine-modified gelatin hydrogel (SF-HTG) were compared. The results showed that SF-LTG possessed better mechanical property and higher biocompatibility. Thus, SF-LTG was selected as a bioactive matrix and loaded with basic fibroblast growth factor (bFGF); subsequently, curcumin-coupled chitosan rods (CCCRs-EGF) enriched with epidermal growth factor (EGF) were added to obtain SF-LTG-bFGF@CCCRs-EGF hydrogels. The results showed that SF-LTG-bFGF@CCCRs-EGF retained the basic structural and mechanical properties of the SF-LTG matrix gel material and underwent multiple loading and orderly release with different activities while displaying antioxidant, anti-inflammatory, antimicrobial, and pro-cellular proliferation activities and orderly regulation of activity during wound healing. Therefore, the SF-LTG-bFGF@CCCRs-EGF hydrogel is of great value in healing complex wounds.

Remendable Cross-Linked Alginate/Gelatin Hydrogels Incorporating Nanofibers for Wound Repair and Regeneration

Wound dressings made from natural-derived polymers are highly valued for their biocompatibility, biodegradability, and biofunctionality. However, natural polymer-based hydrogels can come with their own set of limitations, such as low mechanical strength, limited cell affinity, and the potential cytotoxicity of cross-linkers, which delineate the boundaries of their usage and hamper their practical application. To overcome the limitation of natural-derived polymers, this study utilized a mixture of oxidized alginate and gelatin with 5 mg/mL polycaprolactone (PCL):gelatin nanofiber fragments at a ratio of 7:3 (OGN-7) to develop a hydrogel composite wound dressing that can be injected and has the ability to be remended. The in situ formation of the remendable hydrogel is facilitated by dual cross-linking of oxidized alginate chains with gelatin and PCL/gelatin nanofibers through Schiff-base mechanisms, supported by the physical integration of nanofibers, thereby obviating the need for additional cross-linking agents. Furthermore, OGN-7 exhibits increased stiffness (γ = 79.4-316.3%), reduced gelation time (543 ± 5 to 475 ± 5 s), improved remendability of the hydrogel, and excellent biocompatibility. Notably, OGN-7 achieves full fusion within 1 h of incubation and maintains structural integrity under external stress, effectively overcoming the inherent mechanical weaknesses of natural polymer-based dressings and enhancing biofunctionality. The therapeutic efficacy of OGN-7 was validated through a full-thickness in vivo wound healing analysis, which demonstrated that OGN-7 significantly accelerates wound closure compared to alginate-based dressings and control groups. Histological analysis further revealed that re-epithelialization and collagen deposition were markedly enhanced in the regenerating skin of the OGN-7 group, confirming the superior therapeutic performance of OGN-7. In summary, OGN-7 optimized the synergistic effects of natural polymers, which enhances their collective functionality as a wound dressing and expands their utility across diverse biomedical applications.

Injectable Hydrogels: A Paradigm Tailored with Design, Characterization, and Multifaceted Approaches

Biomaterials denoting self-healing and versatile structural integrity are highly curious in the biomedicine segment. The injectable and/or printable 3D printing technology is explored in a few decades back, which can alter their dimensions temporarily under shear stress, showing potential healing/recovery tendency with patient-specific intervention toward the development of personalized medicine. Thus, self-healing injectable hydrogels (IHs) are stunning toward developing a paradigm for tissue regeneration. This review comprises the designing of IHs, rheological characterization and stability, several benchmark consequences for self-healing IHs, their translation into tissue regeneration of specific types, applications of IHs in biomedical such as anticancer and immunomodulation, wound healing and tissue/bone regeneration, antimicrobial potentials, drugs, gene and vaccine delivery, ocular delivery, 3D printing, cosmeceuticals, and photothermal therapy as well as in other allied avenues like agriculture, aerospace, electronic/electrical industries, coating approaches, patents associated with therapeutic/nontherapeutic avenues, and numerous futuristic challenges and solutions.

Preparation of antibacterial hydrogel from poly(aspartic hydrazide) and quaternized N-[3-(dimethylamino) propyl] methylacrylamide copolymer with antioxidant and hemostatic effects for wound repairing

Hydrogels as wound dressing have attracted extensive attention in past decade because they can provide moist microenvironment to promote wound healing. Herein, this research designed a multifunctional hydrogel with antibacterial property and antioxidant activity fabricated from quaternary ammonium bearing light emitting quaternized TPE-P(DAA-co-DMAPMA) (QTPDD) and poly(aspartic hydrazide) (PAH). The protocatechuic aldehyde (PCA) grafted to the hydrogel through dynamic bond endowed the hydrogel with antioxidant activity and the tranexamic acid (TXA) was loaded to enhance the hemostatic performance. The hydrogel possesses preferable gelation time for injectable application, good antioxidant property and tissue adhesion, improved hemostatic performance fit for wound repairing. Furthermore, the hydrogel has excellent antimicrobial property to both E. coli and S. aureus based on quaternary ammonium structure. The hydrogel also showed good biocompatibility and the in vivo experiments proved this hydrogel can promote the wound repairing rate. This study suggests that TXA/hydrogel with quaternary ammonium structure and dynamic grafted PCA have great potential in wound healing applications.

KGRT peptide incorporated hydrogel with antibacterial activity for wound healing by optimizing cellular functions via ERK/eNOS signaling

Bacterial infected wounds, which is characterized by easy infection, multiple inflammation and slow healing, is a complex symptom, resulting from metabolic disorder of the wound microenvironment. In this study, a series of self-healing double-network hydrogels based on KGRT peptide (Lys-Gly-Arg-Thr) with antibacterial, anti-inflammatory and optimizing cellular functions were designed to promote the healing of infected wounds with full-thickness skin defects. Moreover, the dextran hydrogelintroduces a large number of side chains, which are entangled with each other in the Schiff base network to form an interpenetrating structure. The hydrogel might regulate cell metabolism, differentiation and vascular endothelial growth factor (VEGF) function. Importantly, both in vitro and in vivo data showed that hydrogel not only has good antibacterial properties (99.8 %), but also can eradicate bacterial biofilm, effectively reduce inflammation (down-regulated IL-1β, TNF-α and ROS) and accelerate chronic wound healing process by speeding-up wound closure, increasing granulation tissue thickness, collagen deposition, angiogenesis (up-regulated CD31). The hydrogel could up-regulate mRNA expression of PI3K, AKT, ERK, eNOS, HIF-1α and VEGF, which were correlated with wound healing. Consistently, the hydrogel could promote infected wounds healing and inhibit inflammation through ERK/eNOS signaling pathway. Collectively, hydrogel has excellent clinical application potential for promoting infected wound healing.

Silver-infused lysine crosslinked hydrogel with oxidized regenerated cellulose for prospective advanced wound dressings

The study aimed to develop a multifunctional wound dressing with enhanced antibacterial properties and wound healing promotion. The synthesis process involved preparing oxidized regenerated cellulose (ORC) following a modified procedure, synthesizing chitosan/silver nanoparticles (CS/Ag NPs) via an in-situ reduction method, and subsequently preparing ORC/CS/Lys@Ag NPs hydrogels. Characterization techniques including FTIR, XRD, SEM, and EDS were employed to analyze functional groups, lattice structure, morphology, and elemental composition. Gelation time, swelling behavior, water retention, mechanical properties, viscosity, self-healing capacity, rheological behavior, oxygen permeability, in vitro degradation, release of Ag+, and antibacterial properties were evaluated using various experimental methods. Results indicated that the novel wound dressing has the capability to evenly distribute Ag NPs to effectively counteract bacteria. It can maintain moist conditions for 86 h, resist a sturdy mechanical pressure of 11.3 KPa, and degrade by 11.045 % ± 0.429 within 8 h. Combining its efficient gas exchange abilities, self-repairing function, and biocompatibility, almost full recovery was observed in injured mouse skin within 13 days, highlighting its promising clinical utility.

Polysaccharide hydrogel containing silver nanoparticle@catechol microspheres with photothermal, antibacterial and anti-inflammatory activities for infected-wounds repair

Anti-infection hydrogels have recently aroused enormous attraction, particularly in the treatment of chronic wounds. Herein, silver nanoparticle@catechol formaldehyde resin microspheres (Ag@CFRs) were fabricated by one-step hydrothermal method and subsequently encapsulated in hydrogels which were developed by Schiff base reaction between aldehyde groups in oxidized hyaluronic acid and amino groups in carboxymethyl chitosan. The developed polysaccharide hydrogel exhibited microporous structure, high swelling capacity, favorable mechanical strength, enhanced tissue adhesion and photothermal activities. Additionally, the hydrogel not only ensured long-term and high-efficiency antibacterial performance (99.9 %) toward E. coli and S. aureus, but also realized superior cytocompatibility in vitro. Moreover, based on the triple antibacterial strategies endowed by chitosan, silver nanoparticles and the photothermal properties of catechol microspheres, the composite hydrogel exhibited excellent anti-infection function, significantly downregulated inflammatory factors (TNF-α and IL-1β) and promoted in vivo infected-wound healing. These results demonstrated that the polysaccharide hydrogel containing Ag@CFRs has great potential for infected-wounds repair.

Advancements and Challenges in Self-Healing Hydrogels for Wound Care

This manuscript explores self-healing hydrogels as innovative solutions for diverse wound management challenges. Addressing antibiotic resistance and tailored wound care, these hydrogels exhibit promising outcomes, including accelerated wound closure and tissue regeneration. Advancements in multifunctional hydrogels with controlled drug release, antimicrobial properties, and real-time wound assessment capabilities signal a significant leap toward patient-centered treatments. However, challenges such as scalability, long-term safety evaluation, and variability in clinical outcomes persist. Future directions emphasize personalized medicine, manufacturing innovation, rigorous evaluation through clinical trials, and interdisciplinary collaboration. This manuscript features the ongoing pursuit of effective, adaptable, and comprehensive wound care solutions to transform medical treatments and improve patient outcomes.

Current status of development and biomedical applications of peptide-based antimicrobial hydrogels

Microbial contamination poses a serious threat to human life and health. Through the intersection of material science and modern medicine, advanced bionic hydrogels have shown great potential for biomedical applications due to their unique bioactivity and ability to mimic the extracellular matrix environment. In particular, as a promising antimicrobial material, the synthesis and practical biomedical applications of peptide-based antimicrobial hydrogels have drawn increasing research interest. The synergistic effect of peptides and hydrogels facilitate the controlled release of antimicrobial agents and mitigation of their biotoxicity while achieving antimicrobial effects and protecting the active agents from degradation. This review reports on the progress and trends of researches in the last five years and provides a brief outlook, aiming to provide theoretical background on peptide-based antimicrobial hydrogels and make suggestions for future related work.

Functional hemostatic hydrogels: design based on procoagulant principles

Uncontrolled hemorrhage results in various complications and is currently the leading cause of death in the general population. Traditional hemostatic methods have drawbacks that may lead to ineffective hemostasis and even the risk of secondary injury. Therefore, there is an urgent need for more effective hemostatic techniques. Polymeric hemostatic materials, particularly hydrogels, are ideal due to their biocompatibility, flexibility, absorption, and versatility. Functional hemostatic hydrogels can enhance hemostasis by creating physical circumstances conducive to hemostasis or by directly interfering with the physiological processes of hemostasis. The procoagulant principles include increasing the concentration of localized hemostatic substances or establishing a physical barrier at the physical level and intervention in blood cells or the coagulation cascade at the physiological level. Moreover, synergistic hemostasis can combine these functions. However, some hydrogels are ineffective in promoting hemostasis or have a limited application scope. These defects have impeded the advancement of hemostatic hydrogels. To provide inspiration and resources for new designs, this review provides an overview of the procoagulant principles of hemostatic hydrogels. We also discuss the challenges in developing effective hemostatic hydrogels and provide viewpoints.

Next-generation self-adhesive dressings: Highly stretchable, antibacterial, and UV-shielding properties enabled by tannic acid-coated cellulose nanocrystals

Hydrogels with excellent high-water uptake and flexibility have great potential for wound dressing. However, pure hydrogels without fiber skeleton faced poor water retention, weak fatigue resistance, and mechanical strength to hinder the development of the dressing as next-generation functional dressings. We prepared an ultrafast gelation (6 s) Fe3+/TA-CNC hydrogel (CTFG hydrogel) based on a self-catalytic system and bilayer self-assembled composites. The CTFG hydrogel has excellent flexibility (800% of strain), fatigue resistance (support 60% compression cycles), antibacterial, and self-adhesive properties (no residue or allergy after peeling off the skin). CTFG@S bilayer composites were formed after electrospun silk fibroin (SF) membranes were prepared and adhesive with CTFG hydrogels. The CTFG@S bilayer composites had significant UV-shielding (99.95%), tensile strain (210.9 KPa), and sensitive humidity-sensing properties. Moreover, the integrated structure improved the mechanical properties of electrospun SF membranes. This study would provide a promising strategy for rapidly preparing multifunctional hydrogels for wound dressing.

Pyrogallol loaded chitosan-based polymeric hydrogel for controlling Acinetobacter baumannii wound infections: Synthesis, characterization, and topical application

Antibacterial hydrogels have emerged as a promising approach for wound healing, owing to their ability to integrate antibacterial agents into the hydrogel matrix. Benefiting from its remarkable antibacterial and wound-healing attributes, pyrogallol has been introduced into chitosan-gelatin for the inaugural development of an innovative antibacterial polymeric hydrogel tailored for applications in wound healing. Hence, we observed the effectiveness of pyrogallol in inhibiting the growth of A. baumannii, disrupting mature biofilms, and showcasing robust antioxidant activity both in vitro and in vivo. In addition, pyrogallol promoted the migration of human epidermal keratinocytes and exhibited wound healing activity in zebrafish. These findings suggest that pyrogallol holds promise as a therapeutic agent for wound healing. Interestingly, the pyrogallol-loaded chitosan-gelatin (Pyro-CG) hydrogel exhibited enhanced mechanical strength, stability, controlled drug release, biodegradability, antibacterial activity, and biocompatibility. In vivo results established that Pyro-CG hydrogel promotes wound closure and re-epithelialization in A. baumannii-induced wounds in molly fish. Therefore, the prepared Pyro-CG polymeric hydrogel stands poised as a potent and promising agent for wound healing with antibacterial properties. This holds considerable promise for the development of effective therapeutic interventions to address the increasing menace of A. baumannii-induced wound infections.

Thermoresponsive injectable self-healing hydrogel containing polydopamine-coated Fe/Mo-doped TiO2 nanoparticles for efficient synergistic sonodynamic-chemodynamic-photothermal-chemo therapy

A smart hydrogel loading multifunctional nanoparticles and anticancer drugs was designed to achieve synergistic therapy against tumors with high efficiency and specificity. The thermoresponsive injectable self-healing hydrogel was prepared through the Schiff base between aldehyde-functionalized poly(2-(2-methoxyethoxy) ethyl methacrylate)-co-oligo(ethylene glycol) methacrylate-co-2-hydroxyethyl methacrylate) (P(MEO2MA-co-OEGMA-co-HEMA), APMOH) and hydroxypropyl chitosan (HPCS). The polydopamine-coated Fe/Mo-doped titanium dioxide nanoparticles (PDA@dTiO2 NPs) were prepared and dispersed into the hydrogel with anticancer drug doxorubicin (DOX). PDA@dTiO2 NPs as sonosensitizers can convert oxygen into singlet oxygen (1O2) under ultrasound (US) irradiation, achieving sonodynamic therapy (SDT). They were also considered nanoenzymes, generating oxygen to supply an oxygen source for SDT, producing hydroxyl radical (·OH) to achieve chemodynamic therapy (CDT), and eliminating glutathione (GSH) to enhance the level of oxidative stress. After near-infrared (NIR) irradiation, the temperature of the hydrogel increased due to the photothermal ability of the polydopamine (PDA) layer. When the temperature reached the hydrogel's lower critical solution temperature (LCST), the hydrophilic-hydrophobic transformation occurred, and the hydrogel volume contracted. Consequently, the release rate of PDA@dTiO2 NPs and DOX increased, improving the therapeutic effects. The nanocomposite hydrogel system can achieve synergistic sonodynamic-chemodynamic-photothermal-chemo therapy (SDT-CDT-PTT-CT) for tumors, providing a novel platform for synergistic tumor treatment.

Multifunctional Hydrogels for the Healing of Diabetic Wounds

The healing of diabetic wounds is hindered by various factors, including bacterial infection, macrophage dysfunction, excess proinflammatory cytokines, high levels of reactive oxygen species, and sustained hypoxia. These factors collectively impede cellular behaviors and the healing process. Consequently, this review presents intelligent hydrogels equipped with multifunctional capacities, which enable them to dynamically respond to the microenvironment and accelerate wound healing in various ways, including stimuli -responsiveness, injectable self-healing, shape -memory, and conductive and real-time monitoring properties. The relationship between the multiple functions and wound healing is also discussed. Based on the microenvironment of diabetic wounds, antibacterial, anti-inflammatory, immunomodulatory, antioxidant, and pro-angiogenic strategies are combined with multifunctional hydrogels. The application of multifunctional hydrogels in the repair of diabetic wounds is systematically discussed, aiming to provide guidelines for fabricating hydrogels for diabetic wound healing and exploring the role of intelligent hydrogels in the therapeutic processes.

State of the art, trends, hotspots, and prospects of injection materials for controlling bleeding

Traumatic haemorrhage is a prevalent clinical condition, and effective and timely haemostasis is crucial for the preservation of patients' lives. In recent years, injectable hemostatic materials have gained significant attention due to their excellent hemostatic efficacy, biocompatibility, and biodegradability, making them widely applied in the treatment of incompressible traumatic haemorrhage. Systematic analysis of injectable hemostatic materials is crucial for research in this area. This article provides a comprehensive review of the development and research trends of injectable hemostatic materials over the past 20 years using visualization techniques. Analysis of collaboration and co-citation networks revealed localized research collaboration networks, highlighting the need for enhanced international collaboration in the field of injectable hemostatic materials. Current research focuses primarily on hemostatic materials, hemostatic processes, and hemostatic mechanisms. Injectable hemostatic materials with excellent performance offer promising strategies for wound healing. This review provides a comprehensive and systematic summary of injectable hemostatic materials, offering valuable guidance for the development and clinical application of novel injectable hemostatic materials. Additionally, visualized methodology and mapping analysis are effective data mining methods that provide approaches and strategies for clear knowledge network analysis. These methods facilitate better understanding and interpretation of research dynamics in the field of injectable hemostatic materials, thereby guiding and inspiring future research.

Dual-crosslinked methacrylamide chitosan/poly(ε-caprolactone) nanofibers sequential releasing of tannic acid and curcumin drugs for accelerating wound healing

The objective of this research study is to develop novel composite nanofibers based on methacrylamide chitosan (ChMA)/poly(ε-caprolactone) (PCL) materials by the dual crosslinking and coaxial-electrospinning strategies. The prepared ChMA/PCL composite nanofibers can sequentially deliver tannic acid and curcumin drugs to synergistically inhibit bacterial reproduction and accelerate wound healing. The rapid delivery of tannic acid is expected to inhibit pathogenic microorganisms and accelerate epithelialization in the early stage, while the slow and sustained release of curcumin is with the aim of relieving chronic inflammatory response and inducing dermal tissue maturation in the late stage. Meanwhile, dual-drugs sequentially released from the membrane exhibited a DPPH free radical scavenging rate of ca. 95 % and an antibacterial rate of above 85 %. Moreover, the membrane possessed great biocompatibility in vitro and significantly inhibited the release of pro-inflammatory factors (IL-1β and TNF-α) in vivo. Animal experiments showed that the composite membrane by means of the synergistic effect of polyphenol drugs and ChMA nanofibers, could significantly alleviate macrophage infiltration and accelerate the healing process of wounds. From the above, the as-prepared ChMA-based membrane with a stage-wise release pattern of drugs could be a promising bioengineered construct for wound healing application.

Biomimetic dual-nanozymes with catalytic cascade reactions against diabetic wound infection

Diabetes-related chronic wounds characterized by hyperglycemia and weak alkaline milieu provide numerous advantages for bacteria growth and biofilm formation, setting a myriad of stumbling blocks for wound healing. Therefore, reshaping the spatially and temporally pathological wound microenvironment against bacterial infection is critical to rescue stalled healing progress in diabetes-related chronic wounds. Herein, we demonstrate on the room-temperature construction of a glucose oxidase (GOx)-mimicking and peroxidase (POD)-mimicking dual-nanozymes catalytic cascade system upon the partial reduction of Fe3+ to Fe2+ and the deposition of Au nanoparticles, simultaneously. The as-prepared dual-nanozymes catalytic cascade system possesses the capabilities of reshaping the pathological microenvironments of diabetic wound via glucose consumption and acidification, leading to amplified catalytic cascade activities for sterilization. On the one hand, the GOx-mimicking enzymatic activity of the catalytic cascade system can not only deplete glucose and acidize wound milieu to inhibit bacteria growth, but also utilize the weak alkaline milieu of diabetic wound to provide sufficient H2O2 and a favorable pH for subsequent OH generation. On the other hand, the POD-mimicking enzymatic activity of the catalytic cascade system can continuously produce OH for sterilization under the weak acidic milieu in the presence of abundant H2O2. Benefiting from the simply and mild preparation process and the excellent dual-nanozymes catalytic cascade activities under the deliberate evolved milieus of diabetes-related chronic wounds, our catalytic cascade system exhibits the promising healing effect and clinical translation potential against diabetic wound infection.

Emerging Technology of Nanofiber-Composite Hydrogels for Biomedical Applications

Hydrogels and nanofibers have been firmly established as go-to materials for various biomedical applications. They have been mostly utilized separately, rarely together, because of their distinctive attributes and shortcomings. However, the potential benefits of integrating nanofibers with hydrogels to synergistically combine their functionalities while attenuating their drawbacks are increasingly recognized. Compared to other nanocomposite materials, incorporating nanofibers into hydrogel has the distinct advantage of emulating the hierarchical structure of natural extracellular environment needed for cell and tissue culture. The most important technological aspect of developing "nanofiber-composite hydrogel" is generating nanofibers made of various polymers that are cross-linked and short enough to maintain stable dispersion in hydrated environment. In this review, recent research efforts to develop nanofiber-composite hydrogels are presented, with added emphasis on nanofiber processing techniques. Several notable examples of implementing nanofiber-composite hydrogels for biomedical applications are also introduced.

Versatile and User-Friendly Anti-infective Hydrogel for Effective Wound Healing

Wound dressings play a crucial role in facilitating optimal wound healing and protecting against microbial infections. However, existing commercial options often fall short in addressing chronic infections due to antibiotic resistance and the limited spectrum of activity against both Gram-positive and Gram-negative bacteria frequently encountered at wound sites. Additionally, complex fabrication processes and cumbersome administration strategies pose challenges for cost-effective wound dressing development. Consequently, there is a pressing need to explore easily engineered biocompatible biomaterials as alternative solutions to combat these challenging wound infections. In this study, we present the development of an anti-infective hydrogel, P-BAC (polymeric bactericidal hydrogel), which exhibits simple administration and promotes efficient wound healing. P-BAC is synthesized via a one-step fabrication method that involves the noncovalent cross-linking of poly(vinyl alcohol), N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride-AgCl nanocomposite, and proline. Remarkably, P-BAC demonstrates broad-spectrum antibacterial activity against both planktonic and stationary cells of clinically isolated Gram-positive and Gram-negative bacteria, resulting in a significant reduction of bacterial load (5-7 log reduction). Moreover, P-BAC exhibits excellent efficacy in eradicating bacterial cells within biofilm matrices (>95% reduction). In vivo experiments reveal that P-BAC accelerates wound healing by stimulating rapid collagen deposition at the wound site and effectively inactivates ∼95% of Pseudomonas aeruginosa cells. Importantly, the shear-thinning property of P-BAC simplifies the administration process, enhancing its practicality and usability. Taken together, our findings demonstrate the potential of this easily administrable hydrogel as a versatile solution for effective wound healing with potent anti-infective properties. The developed hydrogel holds promise for applications in diverse healthcare settings, addressing the critical need for improved wound dressing materials.

Injectable and self-healing dual crosslinked gelatin/kappa-carrageenan methacryloyl hybrid hydrogels via host-guest supramolecular interaction for wound healing

Injectable hydrogels based on natural polymers have shown great potential for various tissue engineering applications, such as wound healing. However, poor mechanical properties and weak self-healing ability are still major challenges. In this work, we introduce a host-guest (HG) supramolecular interaction between acrylate-β-cyclodextrin (Ac-β-CD) conjugated on methacrylated kappa-carrageenan (MA-κ-CA) and aromatic residues on gelatin to provide self-healing characteristics. We synthesize an MA-κ-CA to conjugate Ac-β-CD and fabricate dual crosslinked hybrid hydrogels with gelatin to mimic the native extracellular matrix (ECM). The dual crosslinking occurs on the MA-κ-CA backbone through the addition of KCl and photocrosslinking process, which enhances mechanical strength and stability. The hybrid hydrogels exhibit shear-thinning, self-healing, and injectable behavior, which apply easily under a minimally invasive manner and contribute to shear stress during the injection. In-vitro studies indicate enhanced cell viability. Furthermore, scratch assays are performed to examine cell migration and cell-cell interaction. It is envisioned that the combination of self-healing and injectable dual crosslinked hybrid hydrogels with HG interactions display a promising and functional biomaterial platform for wound healing applications.

The application of nanomedicine in clinical settings

As nanotechnology develops in the fields of mechanical engineering, electrical engineering, information and communication, and medical care, it has shown great promises. In recent years, medical nanorobots have made significant progress in terms of the selection of materials, fabrication methods, driving force sources, and clinical applications, such as nanomedicine. It involves bypassing biological tissues and delivering drugs directly to lesions and target cells using nanorobots, thus increasing concentration. It has also proved useful for monitoring disease progression, complementary diagnosis, and minimally invasive surgery. Also, we examine the development of nanomedicine and its applications in medicine, focusing on the use of nanomedicine in the treatment of various major diseases, including how they are generalized and how they are modified. The purpose of this review is to provide a summary and discussion of current research for the future development in nanomedicine.

Role of bioactive magnetic nanoparticles in the prevention of wound pathogenic biofilm formation using smart nanocomposites

BACKGROUND

Biofilm formation and its resistance to various antibiotics is a serious health problem in the treatment of wound infections. An ideal wound dressing should have characteristics such as protection of wound from microbial infection, suitable porosity (to absorb wound exudates), proper permeability (to maintain wound moisture), nontoxicity, and biocompatibility. Although silver nanoparticles (AgNPs) have been investigated as antimicrobial agents, their limitations in penetrating into the biofilm, affecting their efficiency, have consistently been an area for further research.

RESULTS

Consequently, in this study, the optimal amounts of natural and synthetic polymers combination, along with AgNPs, accompanied by iron oxide nanoparticles (IONPs), were utilized to fabricate a smart bionanocomposite that meets all the requirements of an ideal wound dressing. Superparamagnetic IONPs (with the average size of 11.8 nm) were synthesized through co-precipitation method using oleic acid to improve their stability. It was found that the addition of IONPs to bionanocomposites had a synergistic effect on their antibacterial and antibiofilm properties. Cytotoxicity assay results showed that nanoparticles does not considerably affect eukaryotic cells compared to prokaryotic cells. Based on the images obtained by confocal laser scanning microscopy (CLSM), significant AgNPs release was observed when an external magnetic field (EMF) was applied to the bionanocomposites loaded with IONPs, which increased the antibacterial activity and inhibited the formation of biofilm significantly.

CONCLUSION

These finding indicated that the nanocomposite recommended can have an efficient properties for the management of wounds through prevention and treatment of antibiotic-resistant biofilm.

A quaternized chitosan and carboxylated cellulose nanofiber-based sponge with a microchannel structure for rapid hemostasis and wound healing

A hemostatic sponge should perform rapid hemostasis and exhibit antibacterial properties, whilst being non-toxic, breathable, and degradable. This study prepared a hemostatic sponge (CQTC) with microchannels, specifically a microchannel structure based on quaternized chitosan (QCS) and carboxylated cellulose nanofibers (CCNF) obtained by using tannic acid and Cu²⁺ complex (crosslinking agent). The sponge had low density and high porosity, while being degradable. The combination of microchannels and three-dimensional porous structure of CQTC leads to excellent liquid absorption and hemostasis ability, based on a liquid absorption rate test and in vitro hemostasis experiment. In addition, CQTC exhibited excellent antibacterial activity against both gram-negative and gram-positive bacteria, and it promoted wound healing. In conclusion, this porous and microchannel hemostatic sponge has broad application prospects as a clinical wound hemostatic material.

Controlling extrudate volume fraction through poroelastic extrusion of entangled looped fibers

When a suspension of spherical or near-spherical particles passes through a constriction the particle volume fraction either remains the same or decreases. In contrast to these particulate suspensions, here we observe that an entangled fiber suspension increases its volume fraction up to 14-fold after passing through a constriction. We attribute this response to the entanglements among the fibers that allows the network to move faster than the liquid. By changing the fiber geometry, we find that the entanglements originate from interlocking shapes or high fiber flexibility. A quantitative poroelastic model is used to explain the increase in velocity and extrudate volume fraction. These results provide a new strategy to use fiber volume fraction, flexibility, and shape to tune soft material properties, e.g., suspension concentration and porosity, during delivery, as occurs in healthcare, three-dimensional printing, and material repair.

Adhesive, antibacterial and double crosslinked carboxylated polyvinyl alcohol/chitosan hydrogel to enhance dynamic skin wound healing

An available dressing material which promotes skin tissue repair is of significant importance for public health. Moreover, dynamic wounds have special requirements for hydrogel dressings due to their motion state. Correspondingly, a double crosslinked hydrogel was prepared based on amide and coordination bonds from carboxylated polyvinyl alcohol (PC) and chitosan (CS)/Fe³⁺. The hydrogel exhibited excellent swelling ratio and suitable biodegradability, which is beneficial to the tissue repair. The results showed that hydrogels with crosslinked structure possessed better unique properties, such as stronger mechanical (78 kPa of G') and adhesion properties, and shorter self-healing time (5 mins), the change of which was consistent with dynamic wounds. The hydrogel exhibited not only antibacterial activity (98 % fatality rate), but also superior hemostatic capacity during the wound healing process. In addition, the hydrogel could shorten skin healing time to 14 days, and obviously accelerated skin structure reconstruction by promoting angiogenesis and collagen deposition. Therefore, double crosslinked hydrogel is a promising dynamic wound dressing.

Emerging Role of Injectable Dipeptide Hydrogels in Biomedical Applications

Owing to their properties such as biocompatibility, tunable mechanical properties, permeability toward oxygen, nutrients, and the ability to hold a significant amount of water, hydrogels have wide applications in biomedical research. They have been engaged in drug delivery systems, 3D cell culture, imaging, and extracellular matrix (ECM) mimetics. Injectable hydrogels represent a major subset of hydrogels possessing advantages of site-specific conformation with minimal invasive techniques. It preserves the inherent properties of drug/biomolecules and is devoid of any side effects associated with surgery. Various polymeric materials utilized in developing injectable hydrogels are associated with the limitations of toxicity, immunogenicity, tedious manufacturing processes, and lack of easy synthetic tunability. Peptides are an important class of biomaterials that have interesting properties such as biocompatibility, stimuli responsiveness, shear thinning, self-healing, and biosignaling. They lack immunogenicity and toxicity. Therefore, numerous peptide-based injectable hydrogels have been explored in the past, and a few of them have reached the market. In recent years, minimalistic dipeptides have shown their ability to form stable hydrogels through cooperative noncovalent interactions. In addition to inherent properties of lengthy peptide-based injectable hydrogels, dipeptides have the unique advantages of low production cost, high synthetic accessibility, and higher stability. Given the instances of expanding significance of injectable peptide hydrogels in biomedical research and an emerging recent trend of dipeptide-based injectable hydrogels, a timely review on dipeptide-based injectable hydrogels shall highlight various aspects of this interesting class of biomaterials. This concise review that focuses on the dipeptide injectable hydrogel may stimulate the current trends of research on this class of biomaterial to translate its significance as interesting products for biomedical applications.

Supporting the Wound Healing Process-Curcumin, Resveratrol and Baicalin in In Vitro Wound Healing Studies

The purpose of the investigation was to evaluate the effect of the selected bioflavonoids curcumin, resveratrol and baicalin on the wound healing process in an in vitro model. In the study, Balb3t3 and L929 cell lines were used. The first step was the evaluation of the cytotoxicity of the substances tested (MTT assay). Then, using the scratch test (ST), the influence of bioflavonoids on the healing process was evaluated in an in vitro model. The second stage of the work was a mathematical analysis of the results obtained. On the basis of experimental data, the parameters of the Brian and Cousens model were determined in order to determine the maximum value of the cellular and metabolic response that occurs for the examined range of concentrations of selected bioflavonoids. In the MTT assays, no cytotoxic effect of curcumin, resveratrol and baicalin was observed in selected concentrations, while in the ST tests for selected substances, a stimulatory effect was observed on the cell division rate regardless of the cell lines tested. The results obtained encourage further research on the use of substances of natural origin to support the wound healing process.

Icy core-shell composite nanofibers with cooling, antibacterial and healing properties for outdoor burns

Burns are usually difficult to treat because their susceptibe to bacterial infections. When burns is accompanied by hyperthermia, the heat accumulated on the skin will causes extensive tissue damage. Most dressings focus on the treatment process, while ignoring the first-aid treatment to remove hyperthermia. To make matters worse, when outdoors, it is hard to find clean water to wash and cool the burned area. A dressing which can simultaneously realize first-time cooling and repairing treatment of the burned area can shorten treatment time, and is especially beneficial for outdoor use. In this study, a handheld coaxial electrospinning device is developed for preparing platelet-rich plasma @Polycaprolactone-epsilon polylysine (PRP@PCL/ε-PL) core-shell nanofibers. The nanofibers can be synchronously transformed into ice fibers during the spinning process, and directly deposited on the skin. The whole process is convenient to use outdoor. Via dual cooling mechanisms, first aid can take away the excessive heat in the burn area by nanofibers. These core-shell nanofibers also show its excellent antimicrobial and tissue regeneration-promoting properties. Therefore, it achieves first-time cooling and repair treatment of the burned area at the same time. Moreover, due to direct in-situ deposition of this handheld coaxial electrospinning, better antimicrobial properties, and faster healing performance are achieved. By using this integrated strategy that combines cooling, antibacterial and healing promotion, the burn recovery time is shortened from 21 days to 14 days.

The Promising Hydrogel Candidates for Preclinically Treating Diabetic Foot Ulcer: A Systematic Review and Meta-Analysis

Significance: Diabetic foot ulcer (DFU) causes high amputation rates owing to its aberrant wound healing. Traditional dressings cannot effectively contribute to DFU healing. Functional hydrogels have been proposed as a promising novel dressing to treat DFU in future, but the evidence for various hydrogels to heal DFU is still ambiguous. Recent Advances: In accordance with PRISMA and CONSORT guidelines, a meta-analysis was performed to evaluate the efficacy of functional hydrogels. Four electronic databases and one website were used for data searching. Twenty-four animal studies and six clinical trials met the inclusion criteria with a total of 399 diabetic murine models and 278 patients with DFU. Critical Issues: Functional hydrogels accelerated the healing progress for DFU and relieved symptoms in patients. According to their characteristics, the functional hydrogels were divided into antioxidant hydrogel (AOH), antibacterial hydrogel (ABH), multifunctional hydrogel (MFH), proangiogenic hydrogel, and hydrogel promoting proliferation (PPH). By network meta-analysis, AOH and MFH were considered the premium options for treating wounds of diabetic patients at whole stage. Future Direction: Functional hydrogels effectively accelerate healing rates in wounds of diabetic animals. Hydrogels of AOH and MFH might become the ideal candidates for clinical trials on DFU treatment, based on the meta-analyses from the reported work. Early treatment with AOH followed a week later with ABH, which might become an advanced strategy for DFU in future. This information is very important for researchers or/and physicians in taking consideration for alternate application of hydrogel dressings. Scope and Significance: The treatment of DFU imposes a huge burden on medical workers. If DFU is not treated properly, patients will have to suffer from amputation and from spiritual agony. Although various topical dressings have been designated for DFU, the healing ability of those dressings is still unknown well. In this review and meta-analysis, we quantitatively evaluated the reported outcomes of functional hydrogels, pure scaffolds, and controls in 2-week interval. Healing ability of various kinds of functional hydrogels was also assessed in different stages of wound, aiming to screen promising candidates for DFU treatment. This information is valuable in designing smart dressings for researchers or/and physicians in future. Translational Relevance: Considering many external factors like formation of bacterial film and internal factors like hyperglycemia, the progress during DFU healing could involve many biochemical aspects. Persistent inflammation, oxidation stress, and impaired angiogenesis lead to prolonged wound healing and even lethal outcomes. Thus, improvement of topical conditions and inhibition of adverse factors will lead to the alleviated morbidity and even mortality. Clinical Relevance: DFU brings about great burden on patients and medical staffs because of high morbidity and poor prognosis. Improper and powerless treatment might induce high rates of amputation and mortality. Functional hydrogels, mimicking extracellular matrices, would provide the tissue with suitable media and functions to promote DFU healing. The application of various types of hydrogels could be a promising solution to heal DFU and reduce adverse events and costs.

Microenvironment-Based Diabetic Foot Ulcer Nanomedicine

Diabetic foot ulcers (DFU), one of the most serious complications of diabetes, are essentially chronic, nonhealing wounds caused by diabetic neuropathy, vascular disease, and bacterial infection. Given its pathogenesis, the DFU microenvironment is rather complicated and characterized by hyperglycemia, ischemia, hypoxia, hyperinflammation, and persistent infection. However, the current clinical therapies for DFU are dissatisfactory, which drives researchers to turn attention to advanced nanotechnology to address DFU therapeutic bottlenecks. In the last decade, a large number of multifunctional nanosystems based on the microenvironment of DFU have been developed with positive effects in DFU therapy, forming a novel concept of "DFU nanomedicine". However, a systematic overview of DFU nanomedicine is still unavailable in the literature. This review summarizes the microenvironmental characteristics of DFU, presents the main progress of wound healing, and summaries the state-of-the-art therapeutic strategies for DFU. Furthermore, the main challenges and future perspectives in this field are discussed and prospected, aiming to fuel and foster the development of DFU nanomedicines successfully.

Accelerating the excisional wound closure by using the patterned microstructural nanofibrous mats/gentamicin-loaded hydrogel composite scaffold

Ideal artificial tissue scaffolds should provide an in vitro microenvironment comparable to native human skin tissue to direct cell functions, regulate tissue homeostasis, and promote tissue regeneration. A sandwich-like composite scaffold consisting of a hydrogel layer and two aligned nanofibre layers was fabricated and applied as a wound-healing dressing. Gentamicin was preloaded into the hydrogel middle layer and naturally released for antibacterial activity during the healing period. Nanofibrous layers embedded on the top and bottom surfaces of the hydrogel improved the tensile strength fivefold (1560 ​kPa and 465% strain) while serving as a diffusion barrier to reduce the gentamicin initial burst release (30%–15%). Inspired by the extracellular matrix (ECM), the surface of nanofibre top layer was patterned with triangular microarrays using micro-moulding approach to reflect the multidimensional structure of ECM. Biocompatibility of the scaffold is proven from cytotoxicity and haemolysis studies. Fibroblast cells revealed a highly elongated and consistent alignment modulated by the micropatterned fibrous layer and directed their migration towards the wound area. Excisional wounds treated with the scaffold promoted 97.49% wound closure with low inflammation and rapid re-epithelialization and angiogenesis. This scaffold, with its tailored functionality capable of accelerating wound healing, has high potential in tissue engineering applications.