A Biodegradable Antibacterial Nanocomposite Based on Oxidized Bacterial Nanocellulose for Rapid Hemostasis and Wound Healing

Novel design and development of Centella Asiatica extract - loaded poloxamer/ZnO nanocomposite wound closure material to improve anti-bacterial action and enhanced wound healing efficacy in diabetic foot ulcer

Diabetic wounds can occur as a prevalent complication among people diagnosed with diabetes, frequently resulting in the necessity for amputation. The cause and effect of diabetic foot ulcer is complex, involving multiple factors. In the present study, wound healing strategies utilizing nanomaterials have proven to be effective in battling bacterial infections and improve wound regeneration. Poloxamers (PLX) exhibit extensive potential as a viable option for the development of nanomedicines owing to their inherent characteristics of self-assembly and encapsulation. This study aims to design and develop a PLX/ZnO nanocomposite incorporated with Centella Asiatica extract (CAE) for the multi-functional action in the diabetic wound healing treatment. Subsequently physico-chemical characterizations, such as XRD, FTIR, and TEM observations, demonstrated that the ZnO were evenly distributed through the PLX framework. The developed nanocomposite was biocompatible with mouse fibroblast cell line (L929), and it had multiple beneficial characteristics, such as a rapid self-healing process and effective antibacterial action against G+ and G- bacterial pathogens. After being treated with the developed formulation, skin fibroblast cell line and HUVECs demonstrated a substantial increase in their in vitro cell proliferation ability, migration, and tube-forming abilities. The utilization of a CAE@PLX/ZnO nanoformulation presents a viable strategy and a distinctive, encouraging composite for diabetic wound healing treatment.

Antibacterial adhesive based on oxidized tannic acid-chitosan for rapid hemostasis

Currently, bacterial infections and bleeding interfere with wound healing, and multifunctional hydrogels with appropriate blood homeostasis, skin adhesion, and antibacterial activity are desirable. In this study, chitosan-based hydrogels were synthesized using oxidized tannic acid (OTA) and Fe3+ as cross-linkers (CS-OTA-Fe) by forming covalent, non-covalent, and metal coordination bonds between Fe3+ and OTA. Our results demonstrated that CS-OTA-Fe hydrogels showed antibacterial properties against Gram-positive bacteria (Staphylococcus aureus)and Gram-negative bacteria (Escherichia coli), low hemolysis rate (< 2 %), rapid blood clotting ability, in vitro (< 2 min), and in vivo (90 s) in mouse liver bleeding. Additionally, increasing the chitosan concentration from 3 wt% to 4.5 wt% enhanced cross-linking in the network, leading to a significant improvement in the strength (from 106 ± 8 kPa to 168 ± 12 kPa) and compressive modulus (from 50 ± 9 kPa to 102 ± 14 kPa) of hydrogels. Moreover, CS-OTA-Fe hydrogels revealed significant adhesive strength (87 ± 8 kPa) to the cow's skin tissue and cytocompatibility against L929 fibroblasts. Overall, multifunctional CS-OTA-Fe hydrogels with tunable mechanical properties, excellent tissue adhesive, self-healing ability, good cytocompatibility, and fast hemostasis and antibacterial properties could be promising candidates for biomedical applications.

Advances of biological macromolecules hemostatic materials: A review

Achieving hemostasis is a necessary intervention to rapidly and effectively control bleeding. Conventional hemostatic materials currently used in clinical practice may aggravate the damage at the bleeding site due to factors such as poor adhesion and poor adaptation. Compared to most traditional hemostatic materials, polymer-based hemostatic materials have better biocompatibility and offer several advantages. They provide a more effective method of stopping bleeding and avoiding additional damage to the body in case of excessive blood loss. Various hemostatic materials with greater functionality have been developed in recent years for different organs using diverse design strategies. This article reviews the latest advances in the development of polymeric hemostatic materials. We introduce the coagulation cascade reaction after bleeding and then discuss the hemostatic mechanisms and advantages and disadvantages of various polymer materials, including natural, synthetic, and composite polymer hemostatic materials. We further focus on the design strategies, properties, and characterization of hemostatic materials, along with their applications in different organs. Finally, challenges and prospects for the application of hemostatic polymeric materials are summarized and discussed. We believe that this review can provide a reference for related research on hemostatic materials, contributing to the further development of polymer hemostatic materials.

Asymmetric chitosan-derivative/carboxymethylcellulose layer-by-layer film combining antimicrobial and vascular regeneration for the repair of infected wounds

Bacterially infected wounds are a serious threat to patients' lives and health, and multifunctional dressings with antimicrobial properties and healing promotion are urgently needed. Thus, we used the cationic and anionic properties of chitosan (CS)-nerol (N) derivative (CSN) and carboxymethylcellulose (CMC) to prepare asymmetric layer-by-layer self-assembled (LBL) composite films (CSN-CMC LBL films) with antibacterial and healing properties using a spin-coating method. SEM images showed that the CSN-CMC LBL films had completely different degrees of roughness at the bottom (hydrophilic layer) and at the top (hydrophobic layer), with the roughness at the top increasing as the number of layers increased. The CSN and CMC were used to prepare asymmetric LBL films via the electrostatic attraction of -COO- and NH3+. In addition, adhesion and water contact angle tests showed that the CSN-CMC LBL films had enhanced tissue adhesion and good hydrophobicity. These materials had excellent antimicrobial activity and good biocompatibility. Importantly, the animal infection model results showed that CSN-CMC-8 LBL films effectively eliminated the infection in vivo, inhibited inflammation, promoted vascular regeneration, accelerated the epithelialization process, and achieved high quality healing. Overall, the CSN-CMC LBL films in this study showed considerable potential for application in infected wound healing.

Effect of Quorum Sensing Molecules on the Quality of Bacterial Nanocellulose Materials

Bacterial nanocellulose (BNC) biofilms, produced by various bacterial species, such as Gluconacetobacter xylinus, represent a highly promising multifunctional material characterized by distinctive physiochemical properties. These biofilms have demonstrated remarkable versatility as nano biomaterials, finding extensive applications across medical, defense, electronics, optics, and food industries. In contrast to plant cellulose, BNC biofilms exhibit numerous advantages, including elevated purity and crystallinity, expansive surface area, robustness, and excellent biocompatibility, making them exceptional multifunctional materials. However, their production with consistent morphological properties and their transformation into practical forms present challenges. This difficulty often arises from the heterogeneity in cell density, which is influenced by the presence of N-acyl-homoserine lactones (AHLs) serving as quorum sensing signaling molecules during the biosynthesis of BNC biofilms. In this study, we employed surface characterization methodologies including scanning electron microscopy, energy-dispersive spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and atomic force microscopy to characterize BNC biofilms derived from growth media supplemented with varying concentrations of distinct N-acyl-homoserine lactone signaling molecules. The data obtained through these analytical techniques elucidated that the morphological properties of the BNC biofilms were influenced by the specific AHLs, signaling molecules, introduced into the growth media. These findings lay the groundwork for future exploration of leveraging synthetic biology and biomimetic methods for tailoring BNC with predetermined morphological properties.

Synthesis and characterization of thermosensitive 2-hydroxypropyl-trimethylammonium chitin and its antibacterial sponge for noncompressible hemostasis and tissue regeneration

Noncompressible hemorrhage is a leading cause of preventable death in battlefield/civilian trauma. The development of novel injectable and biodegradable hemostatic sponges, with rapid shape recovery and excellent antibacterial activity that can control hemorrhage in noncompressible bleeding sites and promote in situ tissue regeneration is still urgently needed. In this study, thermo/pH sensitive 2-hydroxypropyl-trimethylammonium chitins (QCHs) with low degree of quaternization substitution (DS: 0.07-0.23) and high degree of acetylation (DA: 0.91-0.94) were synthesized homogeneously for the first time. Their chemical compositions including DS and DA were characterized accurately by proton NMR for the first time. High strength QCH based sponges with good water/blood absorbency, rapid shape recovery and good antibacterial activity were prepared without using any crosslinkers but only due to their thermosensitive property, since they are soluble at low temperature but insoluble at high temperature. Compared with commercial products, the QCH sponges with cationic groups had the stronger pro-coagulant ability, better hemostatic effect in normal/heparinized liver perforation and femoral artery models in rats and porcine subclavian arteriovenous resection model. Moreover, the porous structure and biodegradability of the QCH sponges could promote in situ tissue regeneration. Overall, the QCH sponges show great clinical translational potential for noncompressible hemorrhage and tissue regeneration.

Chitosan particles embedded bacterial nanocellulose flat membrane for hemodialysis

The development of bio-based hemodialysis membranes continues to be a challenge. Bacterial nanocellulose (BNC) membranes show potential in hemodialysis but can hardly retain beneficial proteins. Here, chitosan particles/bacterial nanocellulose (CSP/BNC) membranes were designed to efficiently remove uremic toxins and retain beneficial proteins. First, CSPs were synthesized in situ within a BNC membrane by ionic gelation following negative pressure impregnation. Subsequently, these membranes were thoroughly characterized. Compared with the BNC membrane, the pore volume and pore size of the 3 % CSP/BNC membrane decreased by 42.2 % and 32.1 %, respectively. The increased 22.2 times of Young's modulus and 88.9 % of tensile strength in the 3 % CSP/BNC membrane confirmed enhanced mechanical property. The sieving coefficient of bovine serum albumin decreased to 0.05 ± 0.03 in the 3 % CSP/BNC membrane. Moreover, the CSP/BNC membrane exhibited good hemocompatibility and cytocompatibility. The simulated dialysis results showed that the 3 % CSP/BNC membrane exhibited high clearance of urea (16.37 %/cm2) and lysozyme (3.54 %/cm2), while efficiently retaining bovine serum albumin (98.04 %/cm2). This is the first demonstration of the construction of a BNC-based hemodialysis membrane with in situ CSP formation to effectively regulate the pore properties of the membrane, making the CSP/BNC membrane a promising candidate for hemodialysis applications.

Polydopamine contained hydrogel nanocomposites with combined antimicrobial and antioxidant properties for accelerated wound healing

Overproduction of reactive oxygen species (ROS) in infected wounds induces a tremendous inflammatory reaction to delay wound healing. To address this problem, we designed a multifunctional polyacrylamide/PVA-based hydrogel containing synthesized poly(1-glycidyl-3-butylimidazolium salicylate) (polyGBImSal) and fabricated polydopamine-coated polyphenolic nanosheet (PDA@PNS) for wound dressing. The PDA@PNS particles were designed to induce I) antioxidant and anti-inflammatory features through ROS-scavenging and II) cell adhesive properties by the existing polydopamine into the hydrogels. The poly(ionic liquid)-based polyGBImSal was designed to allocate effective hydrogel antimicrobial activity. The fabricated hydrogel nanocomposites showed excellent properties in the swelling ratio, cell adhesiveness, protein adsorption, and anti-inflammatory, proving their general performance for application in wound healing. Furthermore, these hydrogels showed high antimicrobial activity (over 95 %) against three common wound-infecting pathogenic microbes: Escherichia coli, Staphylococcus aureus, and Candida albicans. The healing process of full-thickness dermal wounds in rats was accelerated by applying hydrogel nanocomposites with 0.5 wt% of PDA@PNS and 28 wt% of polyGBImSal. The wound closure contraction attained full closure, reaching 100 %, after 14 days, contrasted with the control group employing commercial wound dressing (Tegaderm), which achieved a closure rate of 68 % within the equivalent timeframe. These results make these hydrogel nanocomposites promising candidates for multifunctional wound dressing applications.

Advances in Stimuli-Responsive Chitosan Hydrogels for Drug Delivery Systems

Sustainable and controllable drug transport is one of the most efficient ways of disease treatment. Due to high biocompatibility, good biodegradability, and low costs, chitosan and its derivatives are widely used in biomedical fields. Specifically, chitosan hydrogel enables drugs to pass through biological barriers because of their abundant amino and hydroxyl groups that can interact with human tissues. Moreover, the multi-responsive nature (pH, temperature, ions strength, and magnetic field, etc.) of chitosan hydrogels makes precise drug release a possibility. Here, the synthesis methods, modification strategies, stimuli-responsive mechanisms of chitosan-based hydrogels, and their recent progress in drug delivery are summarized. Chitosan hydrogels that carry and release drugs through subcutaneous (dealing with wound dressing), oral (dealing with gastrointestinal tract), and facial (dealing with ophthalmic, ear, and brain) are reviewed. Finally, challenges toward clinic application and the future prospects of stimuli-responsive chitosan-based hydrogels are indicated.

Development and performance evaluation of a novel elastic bacterial nanocellulose/polyurethane small caliber artificial blood vessels

There is an increasing demand for small-diameter blood vessels. Currently, there is no clinically available small-diameter artificial vessel. Bacterial nanocellulose (BNC) has vast potential for applications in artificial blood vessels due to its good biocompatibility. At the same time, medical polyurethane (PU) is a highly elastic polymer material widely used in artificial blood vessels. This study reports a composite small-diameter BNC/PU conduit using a non-solvent-induced phase separation method with the highly hydrophilic BNC tube as the skeleton and the hydrophobic polycarbonate PU as the filling material. The results revealed that the compliance and mechanical matching of BNC/PU tubes were higher than BNC tubes; the axial/radial mechanical strength, burst pressure, and suture strength were significantly improved; the blood compatibility and cell compatibility were also excellent. The molecular and subcutaneous embedding tests showed that the composite tubes had lighter inflammatory reactions. The results of the animal substitution experiments showed that the BNC/PU tubes kept blood flow unobstructed without tissue proliferation after implantation in rats for 9 months. Thus, the BNC/PU small-diameter vascular prosthesis had the potential for long-term patency and acted as an ideal material for small-diameter vessels.

Recent advances in harnessing biological macromolecules for wound management: A review

Wound dressings (WDs) are an essential component of wound management and serve as an artificial barrier to isolate the injured site from the external environment, thereby helping to prevent exogenous infections and supporting healing. However, maintaining a moist wound environment, providing protection from infection, good biocompatibility, and allowing for gas exchange, remain a challenge in device design. Functional wound dressings (FWDs) prepared from hybrid biological macromolecule-based materials can enhance efficacy of these systems for skin wound management. This review aims to provide an overview of the state-of-the-art FWDs within the field of wound management, with a specific focus on hybrid biomaterials, techniques, and applications developed over the past five years. In addition, we highlight the incorporation of biological macromolecules in WDs, the emergence of smart WDs, and discuss the existing challenges and future prospects for the development of advanced WDs.

Nanocellulose-Based Hybrid Scaffolds for Skin and Bone Tissue Engineering: A 10-Year Overview

Cellulose, the most abundant polymer on Earth, has been widely utilized in its nanoform due to its excellent properties, finding applications across various scientific fields. As the demand for nanocellulose continues to rise and its ease of use becomes apparent, there has been a significant increase in research publications centered on this biomaterial. Nanocellulose, in its different forms, has shown tremendous promise as a tissue engineered scaffold for regeneration and repair. Particularly, nanocellulose-based composites and scaffolds have emerged as highly demanding materials for both soft and hard tissue engineering. Medical practitioners have traditionally relied on collagen and its analogue, gelatin, for treating tissue damage. However, the limited mechanical strength of these biopolymers restricts their direct use in various applications. This issue can be overcome by making hybrids of these biopolymers with nanocellulose. This review presents a comprehensive analysis of the recent and most relevant publications focusing on hybrid composites of collagen and gelatin with a specific emphasis on their combination with nanocellulose. While bone and skin tissue engineering represents two areas where a majority of researchers are concentrating their efforts, this review highlights the use of nanocellulose-based hybrids in these contexts.

Recent advances and biomedical application of 3D printed nanocellulose-based adhesive hydrogels: A review

Nanocellulose-based tissue adhesives show promise for achieving rapid hemostasis and effective wound healing. Conventional methods, such as sutures and staples, have limitations, prompting the exploration of bioadhesives for direct wound adhesion and minimal tissue damage. Nanocellulose, a hydrolysis product of cellulose, exhibits superior biocompatibility and multifunctional properties, gaining interest as a base material for bioadhesive development. This study explores the potential of nanocellulose-based adhesives for hemostasis and wound healing using 3D printing techniques. Nanocellulose enables the creation of biodegradable adhesives with minimal adverse effects and opens avenues for advanced wound healing and complex tissue regeneration, such as skin, blood vessels, lungs, cartilage, and muscle. This study reviews recent trends in various nanocellulose-based 3D printed hydrogel patches for tissue engineering applications. The review also introduces various types of nanocellulose and their synthesis, surface modification, and bioadhesive fabrication techniques via 3D printing for smart wound healing.

Chitosan/NH2-MIL-125 (Ti) scaffold loaded with doxorubicin for postoperative bone tumor clearance and osteogenesis: An in vitro study

Surgical resection remains the primary treatment modality for bone tumors. However, it is prone to local bone defects and tumor recurrence. Therefore, there is an urgent need for multifunctional biomaterials that combine tumor treatment and bone repair after bone tumor surgery. Herein, a chitosan composite scaffold (CS/DOX@Ti-MOF) was designed for both tumor therapy and bone repair. Among them, the amino-functionalized Ti-based metal-organic framework (NH2-MIL-125 (Ti), Ti-MOF) has a high specific surface area of 1116 m2/g and excellent biocompatibility, and promotes osteogenic differentiation. The doxorubicin (DOX) loading capacity of Ti-MOF was 322 ± 21 mg/g, and DOX@Ti-MOF has perfect antitumor activity. Furthermore, the incorporation of DOX@Ti-MOF improved the physical and mechanical properties of the composite scaffolds, making the scaffold surface rough and favorable for cells to attach. CS/DOX@Ti-MOF retains the unique properties of each component. It responds to the release of DOX in the tumor microenvironment to remove residual tumor cells, followed by providing a site for cell attachment, proliferation, and differentiation. This promotes bone repair and achieves the sequential treatment of postoperative bone tumors. Overall, CS/DOX@Ti-MOF may be a promising substitute for postoperative bone tumor clearance and bone defect repair. It also provides a possible strategy for postoperative bone tumor treatment.

A review of the current state of natural biomaterials in wound healing applications

Skin, the largest biological organ, consists of three main parts: the epidermis, dermis, and subcutaneous tissue. Wounds are abnormal wounds in various forms, such as lacerations, burns, chronic wounds, diabetic wounds, acute wounds, and fractures. The wound healing process is dynamic, complex, and lengthy in four stages involving cells, macrophages, and growth factors. Wound dressing refers to a substance that covers the surface of a wound to prevent infection and secondary damage. Biomaterials applied in wound management have advanced significantly. Natural biomaterials are increasingly used due to their advantages including biomimicry of ECM, convenient accessibility, and involvement in native wound healing. However, there are still limitations such as low mechanical properties and expensive extraction methods. Therefore, their combination with synthetic biomaterials and/or adding bioactive agents has become an option for researchers in this field. In the present study, the stages of natural wound healing and the effect of biomaterials on its direction, type, and level will be investigated. Then, different types of polysaccharides and proteins were selected as desirable natural biomaterials, polymers as synthetic biomaterials with variable and suitable properties, and bioactive agents as effective additives. In the following, the structure of selected biomaterials, their extraction and production methods, their participation in wound healing, and quality control techniques of biomaterials-based wound dressings will be discussed.

Recent research advances on polysaccharide-, peptide-, and protein-based hemostatic materials: A review

Hemorrhage is a potentially life-threatening emergency that can occur at any time or place. Whether traumatic, congenital, surgical, disease-related, or drug-induced, bleeding can lead to severe complications or death. Therefore, the development of efficient hemostatic materials is critical. However, the results and prognosis demonstrated by clinical means of hemostasis do not reach expectations. With the development of technology, novel hemostatic materials have been developed from polysaccharides (chitosan, hyaluronic acid, alginate, cellulose, cyclodextrins, starch, dextran, and carrageenan), peptides (self-assembling peptides), and proteins (silk fibroin, collagen, gelatin, keratin, and thrombin). These new materials exhibit high hemostatic efficacy due to the enhancement or interaction of various hemostatic mechanisms. The main forms include adhesives, sealants, bandages, hemostatic powders, and hemostatic sponges. This article introduces the clotting process and principles of hemostatic methods and reviews the research on polysaccharide-, peptide-, and protein-based hemostatic materials in the last five years. The design ideas and hemostatic principles of polysaccharide-, peptide-, and protein-based hemostatic materials are mainly introduced. Finally, we summarize material designs, advantages, disadvantages, and challenges regarding hemostatic materials.

Quaternized chitosan/oxidized bacterial cellulose cryogels with shape recovery for noncompressible hemorrhage and wound healing

Management of noncompressible torso hemorrhage is an urgent clinical requirement, desiring biomaterials with rapid hemostasis, anti-infection and excellent resilient properties. In this research, we have prepared a highly resilient cryogel with both hemostatic and antibacterial effects by chemical crosslinking and electrostatic interaction. The network structure crosslinked by quaternized chitosan and genipin was interspersed with oxidized bacterial cellulose after lyophilization. The as-prepared cryogel can quickly return to the original volume when soaking in water or blood. The appropriately sized pores in the cryogel help to absorb blood cells and further activate coagulation, while the quaternary ammonium salt groups on quaternized chitosan inhibit bacterial infections. Both cell and animal experiments showed that the cryogel was hypotoxic and could promote the regeneration of wound tissue. This research provides a new pathway for the preparation of double crosslinking cryogels and offers effective and safe biomaterials for the emergent bleeding management of incompressible wounds.

Recent advances of chitosan as a hemostatic material: Hemostatic mechanism, material design and prospective application

Uncontrolled hemorrhage arising from surgery or trauma may cause morbidity and even mortality. Therefore, facilitating control of severe bleeding is imperative for health care worldwide. Among diverse hemostatic materials, chitosan (CS) is becoming the most promising material owing to its non-toxic feature, as well as inherently hemostatic performance. However, further enhancing hemostatic property of CS-based materials without compromising more beneficial functions remains a challenge. In this review, representative hemostatic mechanisms of CS-based materials are firstly discussed in detail, mostly including red blood cells (RBCs) aggregation, platelet adherence and aggregation, as well as interaction with plasma proteins. Also, various forms (involving powder/particle, sponge, hydrogel, nanofiber, and other forms) of CS-based hemostatic materials are systematically summarized, mainly focusing on their design and preparation, characteristics, and comparative analysis of various forms. In addition, varied hemostatic applications are described in detail, such as skin wound hemostasis, liver hemostasis, artery hemostasis, and heart hemostasis. Finally, current challenges and future directions of functional design of CS-based hemostatic materials in diverse hemostatic applications are proposed to inspire more intensive researches.

Facile fabrication and biological investigations of metal oxides intercalated in kaolinite clay-based dressing material to improve wound healing ability in nursing care after post-operative period

The present investigation aims to design and development of hybrid zinc oxide (ZnO) and manganese dioxide (MnO2) nanoparticles (NPs) doped-biopolymer matrix-based cost-effective technique for the synthesis of biocompatible Kaolinite/Chitosan (Ka/CS) nanocomposites (NCs) could be used as agents for wound healing due to their efficiency and low toxicity. The crystallite size, phase purity and surface morphology of the synthesised NCs were investigated systemic analytical methods. The results revealed that the metal oxide nanocomposites presented that in rod-crystalline in shape and additionally exhibits that 20-30 nm in size. In vitro antibacterial analyses demonstrates that NCs have significantly improved bactericidal inhibition efficiency when compared to the bare hybrid NPs and polymeric components. The in vitro biocompatibility observation demonstrates that prepared hybrid-NPs encapsulated NCs have enhanced cell survival rate (>90 %), which was established by MTT assay and Live/Dead fluorescence assay methods at different incubation time. The DPPH assay was used to investigate the synergistic effects of prepared dressing materials increased antioxidant activity. Preliminary research indicates that these nanocomposites, ZnO/MnO2 incorporated and decorated with Ka/CS NCs, could be a significant promoter and potential candidate for use as a robust wound healing agent in post-operative nursing care.

Nanoapatite-Loaded κ-Carrageenan/Poly(vinyl alcohol)-Based Injectable Cryogel for Hemostasis and Wound Healing

Immediate control of excessive bleeding and prevention of infections are of utmost importance in the management of wounds. Cryogels have emerged as promising materials for the rapid release of medication and achieving hemostasis. However, their quick release properties pose the challenge of exposing patients to high concentrations of drugs. In this study, hybrid nanocomposites were developed to address this issue by combining poly(vinyl alcohol) and κ-carrageenan with whitlockite nanoapatite (WNA) particles and ciprofloxacin, aiming to achieve rapid hemostasis and sustained antibacterial effects. A physically cross-linked cryogel was obtained by subjecting a blend of poly(vinyl alcohol) and κ-carrageenan to successive freezing-thawing cycles, followed by the addition of WNA. Furthermore, ciprofloxacin was introduced into the cryogel matrix for subsequent evaluation of its wound healing properties. The resulting gel system exhibited a 3D microporous structure and demonstrated excellent swelling, low cytotoxicity, and outstanding mechanical properties. These characteristics were evaluated through analytical and rheological experiments. The nanocomposite cryogel with 4% whitlockite showed extended drug release of 71.21 ± 3.5% over 21 days and antibacterial activity with a considerable growth inhibition zone (4.19 ± 3.55 cm). Experiments on a rat model demonstrated a rapid hemostasis property of cryogels within an average of 83 ± 4 s and accelerated the process of wound healing with 96.34% contraction compared to the standard, which exhibited only ∼78% after 14 days. The histopathological analysis revealed that the process of epidermal re-epithelialization took around 14 days following the skin incision. The cryogel loaded with WNAs and ciprofloxacin holds great potential for strategic utilization in wound management applications as an effective material for hemostasis and anti-infection purposes.

Sustained antibacterial activity of orthodontic elastomeric ligature ties coated with a novel kombucha-derived bacterial nanocellulose: An in-vitro study

Incipient carious lesions, the most common complication in orthodontic patients with fixed appliances, call for the development of novel preventive dental materials that do not rely on patient adherence. The present study aimed to assess the ability of elastomeric ligatures coated with bacterial nanocellulose (BNC) to deliver sustained antibacterial activity, during the standard 28-day interval between orthodontic appointments, without compromising their mechanical properties. Kombucha membrane was used to produce cellulose as a secondary product from the fermentation of tea broth with symbiotic bacteria and yeast culture. Characterization of BNC-coated elastomeric ligatures was performed using Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy analysis. The samples were pre-treated by immersion first in isopropyl alcohol, then in 8 mL nanocellulose solution for 7 days. Tensile strain and strength of the BNC-coated and conventional ligatures were evaluated using a tensile testing machine. Direct contact and agar diffusion tests were performed to assess the antibacterial activity of nanocellulose. In addition, the release profile of BNC was evaluated. Data analysis was performed by one-way analysis of variance (ANOVA) followed by post-hoc Tukey's test and Wilcoxon signed-rank test. P values less than 0.05 was regarded as significant. There was no statistically significant difference in tensile strain and strength between the BNC-coated and conventional ligatures. The coated ligatures provided sustained antibacterial activity during the required 28 days. The use of BNC-coated elastomeric ligatures in patients with fixed orthodontic appliances might be a promising solution to plaque formation and subsequent enamel decalcification.

Bacterial Cellulose Applied in Wound Dressing Materials: Production and Functional Modification - A Review

In recent years, the development of new type wound dressings has gradually attracted more attention. Bacterial cellulose (BC) is a natural polymer material with various unique properties, such as ultrafine 3D nanonetwork structure, high water retention capacity, and biocompatibility. These properties allow BC to be used independently or in combination with different components (such as biopolymers and nanoparticles) to achieve diverse effects. This means that BC has great potential as a wound dressing. However, systematic summaries for the production and commercial application of BC-based wound dressings are still lacking. Therefore, this review provides a detailed introduction to the production fermentation process of BC, including various production strains and their biosynthetic mechanisms. Subsequently, with regard to the functional deficiencies of bacterial cellulose as a wound dressing, recent research progress in this area is enumerated. Finally, prospects are discussed for the low-cost production and high-value-added product development of BC-based wound dressings.

Multiple Non-Covalent Cross-Linked Multifunctional Strong Hemostatic Agent for Dynamic Exposure Hemostasis

Trauma requires immediate hemostasis during primary care, as well as durable hemostasis that can withstand dynamic wound exposure. Although current hemostatic materials can treat bleeding sites in emergency situations, their mechanical strength and storage conditions limit their practical application. The simultaneous combination of good mechanical properties, storage stability, biocompatibility, and rapid hemostasis of hemostatic materials remains a challenge. In this paper, a novel hemostatic material based on multiple non-covalent bond crosslinking, which has excellent mechanical properties, good biocompatibility, storage stability, and rapid hemostasis ability, is reported. Under the drive of multiple non-covalent bonds, the flowability of hydrogel micro-modules (HM) decreases rapidly within 20 s after exposure to physiological saline. The HM form a gel barrier with a tensile strength of 62.10 kPa and an elongation at break of 1976% under multiple non-covalent bonding. Furthermore, the mechanical properties do not change significantly after 30 days of storage. Cell viability is maintained at over 80% after 3 days of incubation with the cells, and the hemolysis test shows a very low hemolysis rate (2.08%). The hemostatic gel formed by HM effectively prevents secondary bleeding in dynamic hemostasis experiments simulating transportation. This work provides a hemostatic material with comprehensive properties for practical applications.

Antimicrobial peptide-modified AIE visual composite wound dressing for promoting rapid healing of infected wounds

Wound infection is a major problem faced during wound healing. Therefore, it is necessary to develop wound dressings with excellent antimicrobial properties. Here, a smart response system of PVA-TPE/HA-AMP/SF/ALG wound dressing was prepared by a combination of chemical cross-linking and freeze-drying methods. We grafted AMP onto HA to endow the wound dressing with bacterial resistance and slow release of AMP. At the same time, the system detects bacterial activity in real time for precise antimicrobial activity (through the use of PVA-TPE) and modulates inflammation to reduce bacterial infection (through the use of AMP). In addition, the PVA-TPE/HA-AMP/SF/ALG wound dressing has a good three-dimensional mesh structure, which promotes cell proliferation, enhances collagen deposition and angiogenesis, and thus effectively promotes rapid healing of infected wounds. Moreover, it can induce the expression of inflammatory factors such as VEGF, TNF-α, IFN-γ, IL-4 and TGF-β1 in infected wounds through the Wnt/CAMK/p-PKC signaling pathway, inhibit inflammatory responses, promote wound healing and reduce scar formation. Therefore, the PVA-TPE/HA-AMP/SF/ALG wound dressing smart response system shows great promise in infected wound healing.

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.

Cellulose based composite sponges with oriented porous structure and superabsorptive capacity for quick hemostasis

Excessive bleeding is the leading cause of death in accidents and operations. Ca2+ crosslinked carboxyl nanocellulose (CN)/montmorillonite (MMT) composite (CaCNMMT) sponges were prepared by uniform mixing and directional freeze-drying methods which was inspired by the coordination mechanism of blood clot formation and coagulation cascade activation in natural hemostasis process. Carboxyl nanocellulose (CaCN) sponge has instantaneous water absorption capacity, and CaCNMMT sponges could further activate clotting factors. Therefore, CaCNMMT sponges achieved quick hemostasis by efficient concentrating blood, inducing hemocyte aggregation and stimulating coagulation cascade activation based on the synergistic effects of CN and MMT. Blood clotting index of CaCNMMT (15.90 ± 0.52 %) was significantly lower than CaCN (59.3 ± 1.43 %), and APTT time (22 ± 2 s) was almost equivalent to MMT (20 ± 2 s). CaCNMMT sponge showed good quick hemostatic effect on massive hemorrhage in both tail-breaking and liver injury model which provided a new strategy for the application of MMT in hemostatic and trauma treatment fields.

Antibacterial Activity of Molybdenum Oxide-Polyacrylonitrile Composite Membrane with Fast Silver Ion Reduction

The development of hybrid composite antibacterial agents for wound dressing has garnered significant attention due to their remarkable antibacterial efficacy and their potential to mitigate microbial resistance. In this study, we present an approach to designing and fabricating wound dressing membranes, utilizing molybdenum oxide-polyacrylonitrile (MoO3/PAN) hybrid composites through electrospinning. Subsequently, we enhanced the membrane's effectiveness by introducing silver (Ag@MoO3/PAN) into the matrix via a rapid (within one min) green synthesis method under UV irradiation. Initially, we discuss the morphological characteristics and structural attributes of the resulting membranes. Subsequent investigations explore the antibacterial mechanisms of both MoO3 and Ag+, revealing that the incorporation of silver substantially enhanced antibacterial activity. Additionally, we elucidate the surface properties, noting that the introduction of silver increases the surface area of the composite membrane by 25.89% compared with the pristine MoO3/PAN membrane. Furthermore, we observe a 9% reduction in the water contact angle (WCA) for the Ag@MoO3/PAN membrane, indicating improved hydrophilicity. Finally, we analyze the release behavior of the Ag@MoO3/PAN membrane. Our findings demonstrate an initial burst release within the first 7 h, followed by a controlled and sustained release pattern over a period of 7 days.

Photothermal synergistic nitric oxide controlled release injectable self-healing adhesive hydrogel for biofilm eradication and wound healing

The development of injectable self-healing adhesive hydrogel dressings with excellent bactericidal activity and wound healing ability is urgently in demand for combating biofilm infections. Herein, a multifunctional hydrogel (QP/QT-MB) with near-infrared (NIR) light-activated mild photothermal/gaseous antimicrobial activity was developed based on the dynamic reversible borate bonds and hydrogen bonds crosslinking between quaternization chitosan (QCS) derivatives alternatively containing phenylboronic acid and catechol-like moieties in conjunction with the in situ encapsulation of BNN6-loaded mesoporous polydopamine (MPDA@BNN6 NPs). Given the dynamic reversible cross-linking feature, the versatile hybrid hydrogel exhibited injectability, flexibility, and rapid self-healing ability. The numerous phenylboronic acid and catechol-like moieties on the QCS backbone confer the hydrogel with specific bacterial affinity, desirable tissue adhesion, and antioxidant stress ability that enhance bactericidal activity and facilitate the regeneration of infection wounds. Under NIR irradiation, the QP/QT-MB hydrogels exhibited a desirable mild photothermal effect and NIR-activity controllable NO delivery, combined with the endogenous contact antimicrobial activity of hydrogel, contributing jointly to induce dispersal of biofilms and disruption of the bacterial plasma membranes, ultimately leading to bacteria inactivation and biofilm elimination. In vivo experiments demonstrated that the fabricated QP/QT-MB hydrogel platform was capable of inducing efficient eradication of the S. aureus biofilm in a severely infected wound model and accelerating infected wound repair by promoting collagen deposition, angiogenesis, and suppressing inflammatory responses. Additionally, the QP/QT-MB hydrogel demonstrated excellent biocompatibility in vitro and in vivo. Collectively, the hydrogel (QP/QT-MB) reveals great potential application prospects as a promising alternative in the field of biofilm-associated infection treatment.

Combining Chitosan, Stearic Acid, and (Cu-, Zn-) MOFs to Prepare Robust Superhydrophobic Coatings with Biomedical Multifunctionalities

There is an urgent need to develop a series of multifunctional materials with good biocompatibility, high mechanical strength, hemostatic properties, antiadhesion, and anti-infection for applications in wound care. However, successfully developing multifunctional materials is challenging. In this study, two superhydrophobic composite coatings with good biocompatibility, high mechanical strength, strong antifouling and blood repellency, fast hemostasis, and good antibacterial activity are prepared on cotton fabric surface by simple, green, and low-cost one-step dip-coating technology. The results discussed in the manuscript reveals that the two superhydrophobic composite coatings can maintain good mechanical stability, strong water repellency, and durability under various types of mechanical damage, high-temperature treatment, and long-term strong light irradiation. The coatings also exhibit good repellency to various solid pollutants, highly viscous liquid pollutants, and blood. In vitro and in vivo hemostatic experiments show that both composite coatings have good hemostatic and anticlot adhesion properties. More importantly, this superhydrophobic coating prevents bacterial adhesion and growth and released Cu2+ and Zn2+ ions and chitosan to achieve bactericidal properties, thereby protecting injured skin from bacterial infection. The two superhydrophobic coatings enhance the antifouling, antiadhesion, hemostatic, and antibacterial functions of blood-repellent dressings and therefore have broad application prospects in medical and textile fields.

Antibacterial chitosan-based composite sponge with synergistic hemostatic effect for massive haemorrhage

Uncontrollable acute bleeding and wound infection pose significant challenges in emergency treatment and surgical operations. Therefore, the research and development of highly efficient antibacterial hemostatic agents are of great importance in reducing the mortality rate among patients with massive hemorrhage. In this study, we utilized hydrophobically modified chitosan (HM-CS) and gallic acid chitosan (GA-CS) to create a composite sponge (HM/GA-CS) that exhibits complementary advantages. The composite sponge combines the alkyl chain and polyphenol structure, allowing it to adsorb blood cells and plasma proteins simultaneously. This synergistic effect was confirmed through various tests, including blood cell adhesion, plasma protein barrier behavior, and in vitro hemostatic testing. Furthermore, experiments conducted on a rat liver injury model demonstrated that the composite sponge achieved rapid coagulation within 52 s, resulting in significantly lower bleeding volume compared with traditional gauze. In addition, the incorporation of GA-CS into HM-CS enhanced the antibacterial properties of the composite sponge. The antibacterial rate of the composite sponge against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reached 100 % and 98.2 %, respectively. To evaluate its biocompatibility, the composite sponge underwent blood compatibility and cell activity tests, confirming its suitability. The HM/GA-CS sponge holds promising applications in managing cases of massive hemorrhage.

An overview to nanocellulose clinical application: Biocompatibility and opportunities in disease treatment

Recently, the demand for organ transplantation has promptly increased due to the enhanced incidence of body organ failure, the increasing efficiency of transplantation, and the improvement in post-transplant outcomes. However, due to a lack of suitable organs for transplantation to fulfill current demand, significant organ shortage problems have emerged. Developing efficient technologies in combination with tissue engineering (TE) has opened new ways of producing engineered tissue substitutes. The use of natural nanoparticles (NPs) such as nanocellulose (NC) and nano-lignin should be used as suitable candidates in TE due to their desirable properties. Many studies have used these components to form scaffolds and three-dimensional (3D) cultures of cells derived from different tissues for tissue repair. Interestingly, these natural NPs can afford scaffolds a degree of control over their characteristics, such as modifying their mechanical strength and distributing bioactive compounds in a controlled manner. These bionanomaterials are produced from various sources and are highly compatible with human-derived cells as they are derived from natural components. In this review, we discuss some new studies in this field. This review summarizes the scaffolds based on NC, counting nanocrystalline cellulose and nanofibrillated cellulose. Also, the efficient approaches that can extract cellulose with high purity and increased safety are discussed. We concentrate on the most recent research on the use of NC-based scaffolds for the restoration, enhancement, or replacement of injured organs and tissues, such as cartilage, skin, arteries, brain, and bone. Finally, we suggest the experiments and promises of NC-based TE scaffolds.

Applications of Bacterial Cellulose-Based Composite Materials in Hard Tissue Regenerative Medicine

BACKGROUND

Cartilage, bone, and teeth, as the three primary hard tissues in the human body, have a significant application value in maintaining physical and mental health. Since the development of bacterial cellulose-based composite materials with excellent biomechanical strength and good biocompatibility, bacterial cellulose-based composites have been widely studied in hard tissue regenerative medicine. This paper provides an overview of the advantages of bacterial cellulose-based for hard tissue regeneration and reviews the recent progress in the preparation and research of bacterial cellulose-based composites in maxillofacial cartilage, dentistry, and bone.

METHOD

A systematic review was performed by searching the PubMed and Web of Science databases using selected keywords and Medical Subject Headings search terms.

RESULTS

Ideal hard tissue regenerative medicine materials should be biocompatible, biodegradable, non-toxic, easy to use, and not burdensome to the human body; In addition, they should have good plasticity and processability and can be prepared into materials of different shapes; In addition, it should have good biological activity, promoting cell proliferation and regeneration. Bacterial cellulose materials have corresponding advantages and disadvantages due to their inherent properties. However, after being combined with other materials (natural/ synthetic materials) to form composite materials, they basically meet the requirements of hard tissue regenerative medicine materials. We believe that it is worth being widely promoted in clinical applications in the future.

CONCLUSION

Bacterial cellulose-based composites hold great promise for clinical applications in hard tissue engineering. However, there are still several challenges that need to be addressed. Further research is needed to incorporate multiple disciplines and advance biological tissue engineering techniques. By enhancing the adhesion of materials to osteoblasts, providing cell stress stimulation through materials, and introducing controlled release systems into matrix materials, the practical application of bacterial cellulose-based composites in clinical settings will become more feasible in the near future.

Polydopamine functionalized polyurethane shape memory sponge with controllable expansion performance triggered by near-infrared light for incompressible hemorrhage control

Uncontrolled expansion of shape memory sponges face a significant challenge in the treatment of lethal incompressible hemorrhage, which can lead to blood overflow or damage to the surrounding tissue. Herein, we developed a polydopamine functionalized polyurethane shape memory sponge (PDA-TPI-PU) with a controllable degree of expansion by near-infrared (NIR) light-triggered stimulation for the treatment of incompressible hemorrhage. The sponge has excellent liquid absorption performance and robust mechanical strength as well as good photothermal conversion ability. Under NIR light of 0.32 W/cm2, the maximum recovery rate of the fixed-shape compression sponge was 91% within 25 s in air and 80% within 25 s in blood. In the SD rat liver penetrating injury model, compared with commercial medical gelatin sponge and PVA sponge, the PDA-TPI-PU sponge could effectively control the bleeding under the NIR light irradiation and did not cause excessive compression of the wound. The sponge with these characteristics shows potential application prospects as a hemostatic material.

The Potential of Novel Synthesized Carbon Dots Derived Resveratrol Using One-Pot Green Method in Accelerating in vivo Wound Healing

Background

Carbon dots (CDs), a novel nanomaterial, have gained significant attention over the past decade due to their remarkable fluorescence properties, low toxicity, and biocompatibility. These characteristics make them promising in various applications, especially in biomedicine. However, most CDs are currently synthesized using chemical materials, and their biocompatibility falls short of natural compounds. Research on extracting CDs from natural sources is limited, and their potential in biomedicine remains largely unexplored.

Methods

We extracted CDs from resveratrol, a natural plant compound, and enhanced their water solubility using citric acid. Characterization of resveratrol-based carbon dots (RES-CDs) was carried out using various techniques, including UV-Vis, SEM, TEM, FTIR, XRD, and fluorescence spectroscopy. Extensive biocompatibility tests, wound healing assays, cell migration studies, and angiogenesis experiments were conducted using human umbilical vein endothelial cells (HUVEC). In addition, we investigated the biocompatibility and wound healing potential of RES-CDs in an in vivo rat model of inflammation.

Results

RES-CDs exhibited stable yellow-green fluorescence under 365-nanometer ultraviolet light and demonstrated excellent biocompatibility. In wound healing experiments, RES-CDs outperformed resveratrol in terms of cell scratch healing, migration, and tube formation. In a rat skin defect model, RES-CDs promoted wound healing and stimulated the formation of blood vessels and tissue regeneration near the wound site, as evidenced by increased CD31 and VEGF expression.

Conclusion

Resveratrol-derived CDs with enhanced water solubility show superior performance in tissue healing compared to resveratrol. This discovery opens new possibilities for the clinical application of resveratrol-based carbon dots.

Injectable and photothermal antibacterial bacterial cellulose cryogel for rapid hemostasis and repair of irregular and deep skin wounds

For irregular and deep skin wounds, it's difficult for wound dressing to reach the injured site to achieve rapid hemostasis and provide wound protection. Bacterial cellulose (BC) has high strength and natural three-dimensional pore structure, which endows it shape recovery ability after absorbing blood when injected to the wound. Therefore, in the study, an injectable aldehyde bacterial cellulose/polydopamine (DBC/PDA) photothermal cryogel was prepared by oxidation polymerization method for hemostasis and repair of irregular and deep skin wounds. BC was oxidized by NaIO4 to form DBC and dopamine (DA) was introduced into DBC by reacting with the aldehyde group in DBC through Schiff base reaction. Under oxidation effect of NaIO4 and with freezing condition, water crystallization led to local aggregation of DA and DBC, and at the same time DA was oxidized to PDA and polymerized with DA on DBC. After the melting process, the porous cryogel was obtained. The introduction of PDA enhances the photothermal properties of DBC/PDA cryogel. DBC/PDA cryogel can kill most bacteria and provide wound protection under near-infrared light. In vitro and in vivo hemostatic tests show that the DBC/PDA cryogel can quickly absorb blood and stop bleeding. Combined with its good injectable, DBC/PDA cryogel can provide rapid hemostatic and protection in the face of irregular and deep skin wounds.

Wool keratin/zeolitic imidazolate framework-8 composite shape memory sponge with synergistic hemostatic performance for rapid hemorrhage control

Uncontrollable hemorrhage and subsequent wound infection pose severe threats to life, especially in the case of deep, non-compressible, massive bleeding. Here, a wool keratin/zeolitic imidazolate framework-8 (WK/ZIF-8) composite shape memory sponge is prepared by incorporating ZIF-8 nanoparticles into wool keratin. The combination of keratin and ZIF-8 particles not only reduces the effect of ZIF-8 particles on cell viability but also bolsters the mechanical properties of the keratin sponge and endows it with antibacterial efficacy. Due to the synergistic effect of the excellent hemostatic performance of keratin and Zn2+ release from ZIF-8 nanoparticles, the porous structure suitable for blood cell adhesion and the shape recovery ability of sponges, the WK/ZIF-8 composite sponge exhibits superior hemostatic performance to commercial medical sponges in SD rat and rabbit hemorrhage models. In addition, in vitro and in vivo antibacterial experiments demonstrate the anti-infection activity of the composite sponge. Overall, the WK/ZIF-8 composite sponge provides a promising approach to rapidly control bleeding and promote wound healing.

Bacteriosynthetic Degradable Tranexamic Acid-Functionalized Short Fibers for Inhibiting Invisible Hemorrhage

Current research on hemostatic materials have focused on the inhibition of visible hemorrhage, however, invisible hemorrhage is the unavoidable internal bleeding that occurs after trauma or surgery, leading directly to a dramatic drop in hemoglobin and then to anemia and even death. In this study, bacterial nanocellulose (BNC) was synthesized and oxidized from the primary alcohols to carboxyl groups, and then grafted with tranexamic acid through amide bonds to construct degradable nanoscale short fibers (OBNC-TXA), which rapidly activated the coagulation response. The hemostatic material is made up of nanoscale short fibers that can be constructed into different forms such as emulsions, gels, powders, and sponges to meet different clinical applications. In the hemostatic experiments in vitro, the composites had significantly superior pro-coagulant properties due to the rapid aggregation of blood cells. In the coagulation experiments with rat tail amputation and liver trauma hemorrhage models, the group treated with OBNC-TXA1 sponge showed low hemorrhage and inhibited invisible hemorrhage in rectus abdominis muscle defect hemorrhage models, with a rapid recovery of hemoglobin values from 128±5.5 to 165±2.6 g L-1 within 4 days. In conclusion, the degradable short fibers constructed from bacterial nano-cellulose achieved inhibition of invisible hemorrhage in vivo.

Angiogenesis, hemocompatibility and bactericidal effect of bioactive natural polymer-based bilayer adhesive skin substitute for infected burned wound healing

Thermal wounds are complex and lethal with irregular shapes, risk of infection, slow healing, and large surface area. The mortality rate in patients with infected burns is twice that of non-infected burns. Developing multifunctional skin substitutes to augment the healing rate of infected burns is vital. Herein, we 3D printed a hydrogel scaffold comprising carboxymethyl chitosan (CMCs) and oxidized alginate grafted catechol (O-AlgCat) on a hydrophobic electrospun layer, forming a bilayer skin substitute (BSS). The functional layer (FL) was fabricated by physiochemical crosslinking to ensure favorable biodegradability. The gallium-containing hydrophobic electrospun layer or backing layer (BL) could mimic the epidermis of skin, avoiding fluid penetration and offering antibacterial activity. 3D printed FL contains catechol, gallium, and biologically active platelet rich fibrin (PRF) to adhere to both tissue and BL, show antibacterial activity, encourage angiogenesis, cell growth, and migration. The fabricated bioactive BSS exhibited noticeable adhesive properties (P ≤ 0.05), significant antibacterial activity (P ≤ 0.05), faster clot formation, and the potential to promote proliferation (P ≤ 0.05) and migration (P ≤ 0.05) of L929 cells. Furthermore, the angiogenesis was significantly higher (P ≤ 0.05) when evaluated in vivo and in ovo. The BSS-covered wounds healed faster due to low inflammation and high collagen density. Based on the obtained results, the fabricated bioactive BSS could be an effective treatment for infected burn wounds.

Rational Design of Bioactive Materials for Bone Hemostasis and Defect Repair

Everyday unnatural events such as trauma, accidents, military conflict, disasters, and even medical malpractice create open wounds and massive blood loss, which can be life-threatening. Fractures and large bone defects are among the most common types of injuries. Traditional treatment methods usually involve rapid hemostasis and wound closure, which are convenient and fast but may result in various complications such as nerve injury, deep infection, vascular injury, and deep hematomas. To address these complications, various studies have been conducted on new materials that can be degraded in the body and reduce inflammation and abscesses in the surgical area. This review presents the latest research progress in biomaterials for bone hemostasis and repair. The mechanisms of bone hemostasis and bone healing are first introduced and then principles for rational design of biomaterials are summarized. After providing representative examples of hemostatic biomaterials for bone repair, future challenges and opportunities in the field are proposed.

A Novel Injectable Piezoelectric Hydrogel for Periodontal Disease Treatment

Periodontal disease is a multifactorial, bacterially induced inflammatory condition characterized by the progressive destruction of periodontal tissues. The successful nonsurgical treatment of periodontitis requires multifunctional technologies offering antibacterial therapies and promotion of bone regeneration simultaneously. For the first time, in this study, an injectable piezoelectric hydrogel (PiezoGEL) was developed after combining gelatin methacryloyl (GelMA) with biocompatible piezoelectric fillers of barium titanate (BTO) that produce electrical charges when stimulated by biomechanical vibrations (e.g., mastication, movements). We harnessed the benefits of hydrogels (injectable, light curable, conforms to pocket spaces, biocompatible) with the bioactive effects of piezoelectric charges. A thorough biomaterial characterization confirmed piezoelectric fillers' successful integration with the hydrogel, photopolymerizability, injectability for clinical use, and electrical charge generation to enable bioactive effects (antibacterial and bone tissue regeneration). PiezoGEL showed significant reductions in pathogenic biofilm biomass (∼41%), metabolic activity (∼75%), and the number of viable cells (∼2-3 log) compared to hydrogels without BTO fillers in vitro. Molecular analysis related the antibacterial effects to be associated with reduced cell adhesion (downregulation of porP and fimA) and increased oxidative stress (upregulation of oxyR) genes. Moreover, PiezoGEL significantly enhanced bone marrow stem cell (BMSC) viability and osteogenic differentiation by upregulating RUNX2, COL1A1, and ALP. In vivo, PiezoGEL effectively reduced periodontal inflammation and increased bone tissue regeneration compared to control groups in a mice model. Findings from this study suggest PiezoGEL to be a promising and novel therapeutic candidate for the treatment of periodontal disease nonsurgically.

Recent advances in bacterial cellulose-based antibacterial composites for infected wound therapy

Wound infection arising from pathogenic bacteria brought serious trouble to the patient and medical system. Among various wound dressings that are effective in killing pathogenic bacteria, antimicrobial composites based on bacterial cellulose (BC) are becoming the most popular materials due to their success in eliminating pathogenic bacteria, preventing wound infection, and promoting wound healing. However, as an extracellular natural polymer, BC is not inherently antimicrobial, which means that it must be combined with other antimicrobials to be effective against pathogens. BC has many advantages over other polymers, including nano-structure, significant moisture retention, non-adhesion to the wound surface, which has made it superior to other biopolymers. This review introduces the recent advances in BC-based composites for the treatment of wound infection, including the classification and preparation methods of composites, the mechanism of wound treatment, and commercial application. Moreover, their wound therapy applications include hydrogel dressing, surgical sutures, wound healing bandages, and patches are summarized in detail. Finally, the challenges and future prospects of BC-based antibacterial composites for the treatment of infected wounds are discussed.

3D printing-mediated microporous starch hydrogels for wound hemostasis

Starch hydrogels with biodegradability and cytocompatibility are good alternatives to traditional dressings. Herein, oxidized starch hydrogel loaded with coagulation factor Ca2+ ions (CaOMS) is successfully constructed by green hot-extrusion 3D printing technology (HE-3DP). In vitro study demonstrated the good water absorbing capacity (845.15-1194.20%) and blood cell and platelet adhesion of CaOMS to assist hemostasis owing to the boosted network structure density, gel strength, and the release of activated Ca2+ ions. More importantly, in vivo experiments further demonstrated CaOMS could maintain the weight loss caused by blood loss from wounds and has excellent hemostatic (65 s) and wound healing properties by promoting the secretion of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) expression. The advantages of CaOMS, including rapid and effective hemostasis, effective wound healing, low cost, easy usage, and adaptability to fit various wound shapes, make it a promising biomaterial for achieving fast hemostasis and wound healing.

Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis

In traumatized patients, the primary cause of mortality is uncontrollable continuous bleeding and unexpected intraoperative bleeding which is likely to increase the risk of complications and surgical failure. High expansion sponges are effective clinical practice for the treatment of wound bleeding (irregular/deep/narrow) that are caused by capillaries, veins and even arterioles as they possess a high liquid absorption ratio so can absorb blood platelets easily in comparison with traditional haemostasis treatments, which involve compression, ligation, or electrical coagulation etc. When in contact with blood, haemostatic sponges can cause platelet adhesion, aggregation, and thrombosis, preventing blood from flowing out from wounds, triggering the release of coagulation factors, causing the blood to form a stable polymerized fibre protein, forming blood clots, and achieving the goal of wound bleeding control. Haemostatic sponges are found in a variety of shapes and sizes. The aim of this review is to facilitate an overview of recent research around haemostatic sponge materials, products, and technology. This paper reviews the synthesis, properties, and characteristics of haemostatic sponges, together with the haemostasis mechanisms of haemostatic sponges (composite materials), such as chitosan, cellulose, gelatin, starch, graphene oxide, hyaluronic acid, alginate, polyethylene glycol, silk fibroin, synthetic polymers silver nanoparticles, zinc oxide nanoparticles, mesoporous silica nanoparticles, and silica nanoparticles. Also, this paper reviews commercial sponges and their properties. In addition to this, we discuss various in-vitro/in-vivo approaches for the evaluation of the effect of sponges on haemostasis.

Engineered Living Materials for Advanced Diseases Therapy

Natural living materials serving as biotherapeutics exhibit great potential for treating various diseases owing to their immunoactivity, tissue targeting, and other biological activities. In this review, the recent developments in engineered living materials, including mammalian cells, bacteria, viruses, fungi, microalgae, plants, and their active derivatives that are used for treating various diseases are summarized. Further, the future perspectives and challenges of such engineered living material-based biotherapeutics are discussed to provide considerations for future advances in biomedical applications.

Polymer nanomaterials for use as adjuvant surgical tools

Materials employed in the treatment of conditions encountered in surgical and clinical practice frequently face barriers in translation to application. Shortcomings can be generalized through their reduced mechanical stability, difficulty in handling, and inability to conform or adhere to complex tissue surfaces. To overcome an amalgam of challenges, research has sought the utilization of polymer-derived nanomaterials deposited in various fashions and formulations to improve the application and outcomes of surgical and clinical interventions. Clinically prevalent applications include topical wound dressings, tissue adhesives, surgical sealants, hemostats, and adhesion barriers, all of which have displayed the potential to act as superior alternatives to current materials used in surgical procedures. In this review, emphasis will be placed not only on applications, but also on various design strategies employed in fabrication. This review is designed to provide a broad and thought-provoking understanding of nanomaterials as adjuvant tools for the assisted treatment of pathologies prevalent in surgery. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

Chitosan-based hydrogel wound dressing: From mechanism to applications, a review

As promising biomaterials, hydrogels are widely used in the medical engineering field, especially in wound repairing. Compared with traditional wound dressings, such as gauze and bandage, hydrogel could absorb and retain more water without dissolving or losing its three-dimensional structure, thus avoiding secondary injury and promoting wound healing. Chitosan and its derivatives have become hot research topics for hydrogel wound dressing production due to their unique molecular structure and diverse biological activities. In this review, the mechanism of wound healing was introduced systematically. The mechanism of action of chitosan in the first three stages of wound repair (hemostasis, antimicrobial properties and progranulation), the effect of chitosan deacetylation and the molecular weight on its performance are analyzed. Additionally, the recent progress in intelligent and drug-loaded chitosan-based hydrogels and the features and advantages of chitosan were discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.

A hydrogel-based first-aid tissue adhesive with effective hemostasis and anti-bacteria for trauma emergency management

BACKGROUND

Clinical tissue adhesives remain some critical drawbacks for managing emergency injuries, such as inadequate adhesive strength and insufficient anti-infection ability. Herein, a novel, self-healing, and antibacterial carboxymethyl chitosan/polyaldehyde dextran (CMCS/PD) hydrogel is designed as the first-aid tissue adhesive for effective trauma emergency management.

METHODS

We examined the gel-forming time, porosity, self-healing, antibacterial properties, cytotoxicity, adhesive strength, and hemocompatibility. Liver hemorrhage, tail severance, and skin wound infection models of rats are constructed in vivo, respectively.

RESULTS

Results demonstrate that the CMCS/PD hydrogel has the rapid gel-forming (~ 5 s), good self-healing, and effective antibacterial abilities, and could adhere to tissue firmly (adhesive strength of ~ 10 kPa and burst pressure of 327.5 mmHg) with excellent hemocompatibility and cytocompatibility. This suggests the great prospect of CMCS/PD hydrogel in acting as a first-aid tissue adhesive for trauma emergency management. The CMCS/PD hydrogel is observed to not only achieve rapid hemostasis for curing liver hemorrhage and tail severance in comparison to commercial hemostatic gel (Surgiflo ®) but also exhibit superior anti-infection for treating acute skin trauma compared with clinical disinfectant gel (Prontosan ®).

CONCLUSIONS

Overall, the CMCS/PD hydrogel offers a promising candidate for first-aid tissue adhesives to manage the trauma emergency. Because of the rapid gel-forming time, it could also be applied as a liquid first-aid bandage for mini-invasive surgical treatment.

Nanomaterial-Based Scaffolds for Tissue Engineering Applications: A Review on Graphene, Carbon Nanotubes and Nanocellulose

Nanoscale biomaterials have garnered immense interest in the scientific community in the recent decade. This review specifically focuses on the application of three nanomaterials, i.e., graphene and its derivatives (graphene oxide, reduced graphene oxide), carbon nanotubes (CNTs) and nanocellulose (cellulose nanocrystals or CNCs and cellulose nanofibers or CNFs), in regenerating different types of tissues, including skin, cartilage, nerve, muscle and bone. Their excellent inherent (and tunable) physical, chemical, mechanical, electrical, thermal and optical properties make them suitable for a wide range of biomedical applications, including but not limited to diagnostics, therapeutics, biosensing, bioimaging, drug and gene delivery, tissue engineering and regenerative medicine. A state-of-the-art literature review of composite tissue scaffolds fabricated using these nanomaterials is provided, including the unique physicochemical properties and mechanisms that induce cell adhesion, growth, and differentiation into specific tissues. In addition, in vitro and in vivo cytotoxic effects and biodegradation behavior of these nanomaterials are presented. We also discuss challenges and gaps that still exist and need to be addressed in future research before clinical translation of these promising nanomaterials can be realized in a safe, efficacious, and economical manner.

Papaverine loaded injectable and thermosensitive hydrogel system for improving survival of rat dorsal skin flaps

Vasospasm during reconstructive microsurgery is a common, uncertain, and devastating phenomena concerning flap survival. Topical vasodilators as antispasmodic agents are widely used to reduce vasospasm and enhance microvascular anastomosis in reconstructive microsurgery. In this study, thermo-responsive hydrogel (CNH) was fabricated by grafting chitosan (CS) and hyaluronic acid (HA) to poly(N-isopropylacrylamide) (PNIPAM). Papaverine, an anti-spasmodic agent, was then loaded to evaluate its effect on rat skin flap survival. Post-operative flap survival area and water content of rat dorsal skin flap were measured at 7 days after intradermal application of control hydrogel (CNHP0.0) and papaverine loaded hydrogel (CNHP0.4). Tissue malondialdehyde (MDA) content and superoxide dismutase (SOD) activity was measured using enzyme linked immunosorbent assay (ELISA) to determine oxidative stress in flaps. Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) were performed to evaluate flap angiogenesis and inflammatory markers. Results showed that CNHP0.4 hydrogel could reduce tissue edema (35.63 ± 4.01%), improve flap survival area (76.30 ± 5.39%), increase SOD activity and decrease MDA content. Consequently, it also increased mean vessel density, upregulated expression of CD34 and VEGF, decreased macrophage infiltration, and reduced CD68 and CCR7 expression based on IHC staining. Overall, these results indicate that CNHP0.4 hydrogel can enhance angiogenesis with anti-oxidative and anti-inflammatory effects and promote skin flap survival by preventing vascular spasm.

Recent Advances in Collagen Antimicrobial Biomaterials for Tissue Engineering Applications: A Review

Biomaterial-based therapies have been receiving attention for treating microbial infections mainly to overcome the increasing number of drug-resistant bacterial strains and off-target impacts of therapeutic agents by conventional strategies. A fibrous, non-soluble protein, collagen, is one of the most studied biopolymers for the development of antimicrobial biomaterials owing to its superior physicochemical, biomechanical, and biological properties. In this study, we reviewed the different approaches used to develop collagen-based antimicrobial devices, such as non-pharmacological, antibiotic, metal oxide, antimicrobial peptide, herbal extract-based, and combination approaches, with a particular focus on preclinical studies that have been published in the last decade.