Review collagen-based biomaterials for wound healing

The current status of various preclinical therapeutic approaches for tendon repair

Tendons are fibroblastic structures that link muscle and bone. There are two kinds of tendon injuries, including acute and chronic. Each form of injury or deterioration can result in significant pain and loss of tendon function. The recovery of tendon damage is a complex and time-consuming recovery process. Depending on the anatomical location of the tendon tissue, the clinical outcomes are not the same. The healing of the wound process is divided into three stages that overlap: inflammation, proliferation, and tissue remodeling. Furthermore, the curing tendon has a high re-tear rate. Faced with the challenges, tendon injury management is still a clinical issue that must be resolved as soon as possible. Several newer directions and breakthroughs in tendon recovery have emerged in recent years. This article describes tendon injury and summarizes recent advances in tendon recovery, along with stem cell therapy, gene therapy, Platelet-rich plasma remedy, growth factors, drug treatment, and tissue engineering. Despite the recent fast-growing research in tendon recovery treatment, still, none of them translated to the clinical setting. This review provides a detailed overview of tendon injuries and potential preclinical approaches for treating tendon injuries.

Recombinant humanized type III collagen inhibits ovarian cancer and induces protective anti-tumor immunity by regulating autophagy through GSTP1

Ovarian cancer (OC) is one of the leading causes of death from malignancy in women and lacks safe and efficient treatment. The novel biomaterial, recombinant humanized collagen type III (rhCOLIII), has been reported to have various biological functions, but its role in OC is unclear. This study aimed to reveal the function and mechanism of action of rhCOLIII in OC. We developed an injectable recombinant human collagen (rhCOL)-derived material with a molecular weight of 45 kDa, with a stable triple helix structure, high biocompatibility, water solubility and biosafety. The anti-tumor activity of rhCOLIII was comprehensively evaluated through in vitro and in vivo experiments. In vitro, our results showed that rhCOLIII inhibited the proliferation, migration, and invasion of ovarian cancer cells (OCCs), and induced apoptosis. In addition, rhCOLIII not only inhibited autophagy of OCCs but also increased the expression of MHC-1 molecule within OCCs. To further elucidate the mechanism of rhCOLIII in OC, we conducted joint analysis of RNA-Seq and proteomics, and found that rhCOLIII exerted anti-tumor function and autophagy inhibition by downregulating Glutathione S-transferase P1 (GSTP1). Furthermore, various rescue experiments were designed to demonstrate that rhCOLIII suppressed autophagy and proliferation of OCCs by mediating GSTP1. In vivo, we found that rhCOLIII could inhibit tumor growth and promote CD8+ T cell infiltration. Our results indicate that rhCOLIII has great anti-tumor potential activity in OC, and induces protective anti-tumor immunity by regulating autophagy through GSTP1. These findings illustrate the potential therapeutic prospects of rhCOLIII for OC treatment.

Collagen as the extracellular matrix biomaterials in the arena of medical sciences

Collagen is a multipurpose material that has several applications in the health care, dental care, and pharmaceutical industries. Crosslinked compacted solids or lattice-like gels can be made from collagen. Biocompatibility, biodegradability, and wound-healing properties make collagen a popular scaffold material for cardiovascular, dentistry, and bone tissue engineering. Due to its essential role in the control of several of these processes, collagen has been employed as a wound-healing adjunct. It forms a major component of the extracellular matrix and regulates wound healing in its fibrillar or soluble forms. Collagen supports cardiovascular and other soft tissues. Oral wounds have been dressed with resorbable forms of collagen for closure of graft and extraction sites, and to aid healing. This present review is concentrated on the use of collagen in bone regeneration, wound healing, cardiovascular tissue engineering, and dentistry.

Peptidic "Molecular Beacon" for Collagen

Collagen-mimetic peptides (CMP) have been invaluable tools for understanding the structure and function of collagen, which is the most abundant protein in animals. CMPs have also been developed as probes that detect damaged collagen because of the specificity required to form a collagen triple helix. These probes are not, however, ratiometric. Here, we used EPR spectroscopy to determine the end-to-end distances of CMPs that do not form stable homotrimeric helices. We found that those distances are shorter than the distances in the context of a collagen triple helix, suggesting their potential utility as a "molecular beacon" and guiding the choice and location of a pendant fluorophore-quencher pair. We then showed that a molecular beacon based on a glycine-(2S,4S)-4-fluoroproline-(2S,4R)-4-hydroxyproline tripeptide repeat and EDANS-DABCYL pair enabled the ratiometric detection of its binding to both other CMPs and natural mammalian collagen. These results provide guidance for the development of a new modality for detecting damaged collagen in physiological settings.

Recombinant collagen for the repair of skin wounds and photo-aging damage

The skin, being the body's primary defense mechanism, is susceptible to various injuries such as epidermal wounds, natural aging, and ultraviolet-induced damage. As a result, there is growing interest in researching skin repair methods. Traditional animal-derived collagen, widely available on the market, poses risks due to its immunogenicity and potential for viral contamination. In contrast, recombinant collagen sourced from human genes offers a safer alternative. To investigate the potential of human recombinant collagen in skin repair, our research team applied two types, type I human collagen (Col I) and CF-1552(I), to two different skin injury models: a wound-healing model and a photo-aging model. Our findings indicate that both Col I and CF-1552(I) effectively enhance wound healing and repair skin damaged by ultraviolet exposure. Notably, CF-1552(I) showed effects comparable to Col I in promoting cell proliferation in the wound-healing model and increasing malondialdehyde content in the photo-aging model, suggesting that CF-1552(I) may offer greater potential for skin repair compared to the larger Col I molecule.

An Overview of Wound Dressing Materials

Wounds are an increasing global concern, mainly due to a sedentary lifestyle, frequently associated with the occidental way of life. The current prevalence of obesity in Western societies, leading to an increase in type II diabetes, and an elderly population, is also a key factor associated with the problem of wound healing. Therefore, it stands essential to find wound dressing systems that allow for reestablishing the skin integrity in the shortest possible time and with the lowest cost, avoiding further damage and promoting patients' well-being. Wounds can be classified into acute or chronic, depending essentially on the duration of the healing process, which is associated withextent and depth of the wound, localization, the level of infection, and the patient's health status. For each kind of wound and respective healing stage, there is a more suitable dressing. The aim of this review was to focus on the possible wound dressing management, aiming for a more adequate healing approach for each kind of wound.

A potential therapeutic strategy of an innovative probiotic formulation toward topical treatment of diabetic ulcer: an in vivo study

BACKGROUND

The probiotic potential of Lacticacid bacteria has been studied in various medical complications, from gastrointestinal diseases to antibiotic resistance infections recently. Moreover, diabetic ulcer (DU) is known as one of the most significant global healthcare concerns, which comprehensively impacts the quality of life for these patients. Given that the conventional treatments of DUs have failed to prevent later complications completely, developing alternative therapies seems to be crucial.

METHODS

We designed the stable oleogel-based formulation of viable probiotic cells, including Lactobacillus rhamnosus (L. rhamnosus), Lactobacillus casei (L. casei), Lactobacillus fermentum (L. fermentum), and Lactobacillus acidophilus (L. acidophilus) individually to investigate their effect on wound healing process as an in vivo study. The wound repair process was closely monitored regarding morphology, biochemical, and histopathological changes over two weeks and compared it with the effects of topical tetracycline as an antibiotic approach. Furthermore, the antibiofilm activity of probiotic bacteria was assessed against some common pathogens.

RESULTS

The findings indicated that all tested lactobacillus groups (excluded L. casei) included in the oleogel-based formulation revealed a high potential for repairing damaged skin due to the considerably more levels of hydroxyproline content of tissue samples along with the higher numerical density of mature fibroblasts cell and volume density of hair follicles, collagen fibrils, and neovascularization in comparison with antibiotic and control groups. L. acidophilus and L. rhamnosus showed the best potential of wound healing among all lactobacillus species, groups treated by tetracycline and control groups. Besides, L. rhamnosus showed a significant biofilm inhibition activity against tested pathogens.

CONCLUSIONS

This experiment demonstrated that the designed formulations containing probiotics, particularly L. acidophilus and L. rhamnosus, play a central role in manipulating diabetic wound healing. It could be suggested as an encouraging nominee for diabetic wound-healing alternative approaches, though further studies in detailed clinical trials are needed.

Synergistic potential of gellan gum methacrylate and keratin hydrogel for visceral hemostasis and skin tissue regeneration

In recent years, the development of biodegradable hydrogels as an alternative over the traditional wound dressing has become increasingly significant. These specific hydrogels are able to offer suitable microenvironments to further aid the process of tissue or organ regeneration. However, application of biodegradable hydrogels in clinical medicine remains uncommon due to most biodegradable hydrogels struggle with achieving satisfactory adhesiveness property, high mechanical support and cell compatibility simultaneously. In order to overcome these constraints and enhance the applicability of biodegradable hydrogels, methods have been employed in this study. By reacting gellan gum with methacrylic anhydride and incorporating a biodegradable protein, keratin, we endowed the hydrogels with high pliability via photo-polymerization chain extension, thereby obtaining a biodegradable hydrogel with exceptional properties. Through a series of in vitro tests, GGMA/keratin hydrogels exhibited great cell compatibility via providing an appropriate environment for cell proliferation. Furthermore, this hydrogel not only exhibits extraordinary adhesive ability on visceral tissues but also extends to scenarios involving skin or organ damage, offering valuable assistance in wound healing. Our design provides a suitable platform for cell proliferation and tissue regeneration, which shows prospects for future medical research and clinical applications.

Contactless mechanical stimulation of the skin using shear waves

The skin, the outermost organ of the human body, is vital for sensing and responding to stimuli through mechanotransduction. It is constantly exposed to mechanical stress. Consequently, various mechanical therapies, including compression, massage, and microneedling, have become routine practices for skin healing and regeneration. However, these traditional methods require direct skin contact, restricting their applicability. To address this constraint, we developed shear wave stimulation (SWS), a contactless mechanical stimulation technique. The effectiveness of SWS was compared with that of a commercial compression bioreactor used on reconstructed skin at various stages of maturity. Despite the distinct stimulus conditions applied by the two methods, SWS yielded remarkable outcomes, similar to the effects of the compression bioreactor. It significantly increased the shear modulus of tissue-engineered skin, heightened the density of collagen and elastin fibers, and resulted in an augmentation of fibroblasts in terms of their number and length. Notably, SWS exhibited diverse effects in the low- and high-frequency modes, highlighting the importance of fine-tuning the stimulus intensity. These results unequivocally demonstrated the capability of SWS to enhance the mechanical functions of the skin in vitro, making it a promising option for addressing wound healing and stretch mark recovery.

Effects of blood and root-dentin cleaning on the porosity and bond strength of a collagen bioceramic material

To assess the effect of cleaning protocols on dentin contaminated with blood in reparative endodontic materials, bovine root samples were divided: no contamination (N); contamination (P); contamination and cleaning with saline (S), 2.5% NaOCl+saline (Na) or 2.5% NaOCl+17% EDTA+saline (NaE) and filled with: mineral trioxide aggregate (MTA), calcium-aluminate-cement (C), or C+collagen (Ccol) (n=13). The samples were evaluated for porosity, chemical composition, and bond strength. MTA porosity was lower than C (p=0.02) and higher than Ccol (p<0.001). P and NaE were similar (p=1.00), but higher than the other groups (p<0.001). MTA bond strength was similar to Ccol (p=0.777) and lower than C (p=0.028). P presented lower bond strength than the N (p<0.001); S and Na were similar to each other (p=0.969), but higher than P and lower than N (p<0.001). It was observed a predominance of mixed and cohesive failures. None of the samples showed Ca/P ratio values similar to human hydroxyapatite. This study showed that contamination with blood increased the materials porosity, but dentin cleaning with 2.5% NaOCl reduced this effect, and the collagen additive reduced the material porosity. Furthermore, blood contamination reduced the materials bond strength, and cleaning with saline or 2.5% NaOCl diminished this effect.

Research Progress on Starfish Outbreaks and Their Prevention and Utilization: Lessons from Northern China

Starfish are keystone species as predators in benthic ecosystems, but when population outbreaks occur, this can have devastating consequences ecologically. Furthermore, starfish outbreaks and invasions can have adverse impact economically by impacting shellfish aquaculture. For example, an infestation of starfish in Qingdao led to a 50% reduction in sea cucumber production and an 80% reduction in scallop production, resulting in an economic loss of approximately RMB 100 million to oyster and other shellfish industries. Addressing the imperative need to proactively mitigate starfish invasions requires comprehensive research on their behavior and the underlying mechanisms of outbreaks. This review scrutinizes the historical patterns of outbreaks among diverse starfish species across various regions, delineates the factors contributing to the proliferation of Asterias amurensis in Chinese waters, articulates preventive and remedial strategies, and outlines the potential for the sustainable utilization of starfish.

In Operando Imaging Electrostatic-Driven Disassembly and Reassembly of Collagen Nanostructures

Collagen is the most abundant protein in tissue scaffolds in live organisms. Collagen can self-assemble in vitro, which has led to a number of biotechnological and biomedical applications. To understand the dominant factors that participate in the formation of collagen nanostructures, here we study in real time and with nanoscale resolution the disassembly and reassembly of collagens. We implement a high-speed force microscope, which provides in situ high spatiotemporal resolution images of collagen nanostructures under changing pH conditions. The disassembly and reassembly are dominated by the electrostatic interactions among amino-acid residues of different molecules. Acidic conditions favor disassembly by neutralizing negatively charged residues. The process sets a net repulsive force between collagen molecules. A neutral pH favors the presence of negative and positively charged residues along the collagen molecules, which promotes their electrostatic attraction. Molecular dynamics simulations reproduce the experimental behavior and validate the electrostatic-based model of the disassembly and reassembly processes.

Unveiling Trends: Nanoscale Materials Shaping Emerging Biomedical Applications

The realm of biomedical materials continues to evolve rapidly, driven by innovative research across interdisciplinary domains. Leveraging big data from the CAS Content Collection, this study employs quantitative analysis through natural language processing (NLP) to identify six emerging areas within nanoscale materials for biomedical applications. These areas encompass self-healing, bioelectronic, programmable, lipid-based, protein-based, and antibacterial materials. Our Nano Focus delves into the multifaceted utilization of nanoscale materials in these domains, spanning from augmenting physical and electronic properties for interfacing with human tissue to facilitating intricate functionalities like programmable drug delivery.

Comprehensive Assessment of Collagen/Sodium Alginate-Based Sponges as Hemostatic Dressings

In our search for a biocompatible composite hemostatic dressing, we focused on the design of a novel biomaterial composed of two natural biological components, collagen and sodium alginate (SA), cross-linked using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) and oxidized sodium alginate (OSA). We conducted a series of tests to evaluate the physicochemical properties, acute systemic toxicity, skin irritation, intradermal reaction, sensitization, cytotoxicity, and in vivo femoral artery hemorrhage model. The results demonstrated the excellent biocompatibility of the collagen/sodium alginate (C/SA)-based dressings before and after crosslinking. Specifically, the femoral artery hemorrhage model revealed a significantly shortened hemostasis time of 132.5 ± 12.82 s for the EDC/NHS cross-linked dressings compared to the gauze in the blank group (hemostasis time of 251.43 ± 10.69 s). These findings indicated that C/SA-based dressings exhibited both good biocompatibility and a significant hemostatic effect, making them suitable for biomedical applications.

Preliminary Evaluation of Bioactive Collagen-Polyphenol Surface Nanolayers on Titanium Implants: An X-ray Photoelectron Spectroscopy and Bone Implant Study

To endow an implant surface with enhanced properties to ensure an appropriate seal with the host tissue for inflammation/infection resistance, next-generation bone implant collagen-polyphenol nanolayers were built on conventional titanium surfaces through a multilayer approach. X-ray Photoelectron Spectroscopy (XPS) analysis was performed to investigate the chemical arrangement of molecules within the surface layer and to provide an estimate of their thickness. A short-term (2 and 4 weeks) in vivo test of bone implants in a healthy rabbit model was performed to check possible side effects of the soft surface layer on early phases of osteointegration, leading to secondary stability. Results show the building up of the different nanolayers on top of titanium, resulting in a final composite collagen-polyphenol surface and a layer thickness of about 10 nm. In vivo tests performed on machined and state-of-the-art microrough titanium implants do not show significant differences between coated and uncoated samples, as the surface microroughness remains the main driver of bone-to-implant contact. These results confirm that the surface nanolayer does not interfere with the onset and progression of implant osteointegration and prompt the green light for specific investigations of the potential merits of this bioactive coating as an enhancer of the device/tissue seal.

Strategies to enhance the efficacy of FGF2-based therapies for skin wound healing

Basic fibroblast growth factor (FGF2 or bFGF) is critical for optimal wound healing. Experimental studies show that local application of FGF2 is a promising therapeutic approach to stimulate tissue regeneration, including for the treatment of chronic wounds that have a low healing potential or are characterised by a pathologically altered healing process. However, the problem of low efficiency of growth factors application due to their rapid loss of biological activity in the aggressive proteolytic environment of the wound remains. Therefore, ways to preserve the efficacy of FGF2 for wound treatment are being actively developed. This review considers the following strategies to improve the effectiveness of FGF2-based therapy: (1) use of vehicles/carriers for delivery and gradual release of FGF2; (2) chemical modification of FGF2 to increase the stability of the molecule; (3) use of genetic constructs encoding FGF2 for de novo synthesis of protein in the wound. In addition, this review discusses FGF2-based therapeutic strategies that are undergoing clinical trials and demonstrating the efficacy of FGF2 for skin wound healing.

Silk Fibroin and Its Nanocomposites for Wound Care: A Comprehensive Review

For most individuals, wound healing is a highly organized, straightforward process, wherein the body transitions through different phases in a timely manner. However, there are instances where external intervention becomes necessary to support and facilitate different phases of the body's innate healing mechanism. Furthermore, in developing countries, the cost of the intervention significantly impacts access to treatment options as affordability becomes a determining factor. This is particularly true in cases of long-term wound treatment and management, such as chronic wounds and infections. Silk fibroin (SF) and its nanocomposites have emerged as promising biomaterials with potent wound-healing activity. Driven by this motivation, this Review presents a critical overview of the recent advancements in different aspects of wound care using SF and SF-based nanocomposites. In this context, we explore various formats of hemostats and assess their suitability for different bleeding situations. The subsequent sections discuss the primary causes of nonhealing wounds, i.e., prolonged inflammation and infections. Herein, different treatment strategies to achieve immunomodulatory and antibacterial properties in a wound dressing were reviewed. Despite exhibiting excellent pro-healing properties, few silk-based products reach the market. This Review concludes by highlighting the bottlenecks in translating silk-based products into the market and the prospects for the future.

Molecular and cellular signalling pathways for promoting neural tissue growth - A tissue engineering approach

Neural tissue engineering is a sub-field of tissue engineering that develops neural tissue. Damaged central and peripheral nervous tissue can be fabricated with a suitable scaffold printed with biomaterials. These scaffolds promote cell growth, development, and migration, yet they vary according to the biomaterial and scaffold printing technique, which determine the physical and biochemical properties. The physical and biochemical properties of scaffolds stimulate diverse signalling pathways, such as Wnt, NOTCH, Hedgehog, and ion channels- mediated pathways to promote neuron migration, elongation and migration. However, neurotransmitters like dopamine, acetylcholine, gamma amino butyric acid, and other signalling molecules are critical in neural tissue engineering to tissue fabrication. Thus, this review focuses on neural tissue regeneration with a tissue engineering approach highlighting the signalling pathways. Further, it explores the interaction of the scaffolds with the signalling pathways for generating neural tissue.

Dissolvable Immunomodulatory Microneedles for Treatment of Skin Wounds

Sustained inflammation can halt or delay wound healing, and macrophages play a central role in wound healing. Inflammatory macrophages are responsible for the removal of pathogens, debris, and neutrophils, while anti-inflammatory macrophages stimulate various regenerative processes. Recombinant human Proteoglycan 4 (rhPRG4) is shown to modulate macrophage polarization and to prevent fibrosis and scarring in ear wound healing. Here, dissolvable microneedle arrays (MNAs) carrying rhPRG4 are engineered for the treatment of skin wounds. The in vitro experiments suggest that rhPRG4 modulates the inflammatory function of bone marrow-derived macrophages. Degradable and detachable microneedles are developed from gelatin methacryloyl (GelMA) attach to a dissolvable gelatin backing. The developed MNAs are able to deliver a high dose of rhPRG4 through the dissolution of the gelatin backing post-injury, while the GelMA microneedles sustain rhPRG4 bioavailability over the course of treatment. In vivo results in a murine model of full-thickness wounds with impaired healing confirm a decrease in inflammatory biomarkers such as TNF-α and IL-6, and an increase in angiogenesis and collagen deposition. Collectively, these results demonstrate rhPRG4-incorporating MNA is a promising platform in skin wound healing applications.

Recent advancements in natural polymers-based self-healing nano-materials for wound dressing

The field of wound healing has witnessed remarkable progress in recent years, driven by the pursuit of advanced wound dressings. Traditional dressing materials have limitations like poor biocompatibility, nonbiodegradability, inadequate moisture management, poor breathability, lack of inherent therapeutic properties, and environmental impacts. There is a compelling demand for innovative solutions to transcend the constraints of conventional dressing materials for optimal wound care. In this extensive review, the therapeutic potential of natural polymers as the foundation for the development of self-healing nano-materials, specifically for wound dressing applications, has been elucidated. Natural polymers offer a multitude of advantages, possessing exceptional biocompatibility, biodegradability, and bioactivity. The intricate engineering strategies employed to fabricate these polymers into nanostructures, thereby imparting enhanced mechanical robustness, flexibility, critical for efficacious wound management has been expounded. By harnessing the inherent properties of natural polymers, including chitosan, alginate, collagen, hyaluronic acid, and so on, and integrating the concept of self-healing materials, a comprehensive overview of the cutting-edge research in this emerging field is presented in the review. Furthermore, the inherent self-healing attributes of these materials, wherein they exhibit innate capabilities to autonomously rectify any damage or disruption upon exposure to moisture or body fluids, reducing frequent dressing replacements have also been explored. This review consolidates the existing knowledge landscape, accentuating the benefits and challenges associated with these pioneering materials while concurrently paving the way for future investigations and translational applications in the realm of wound healing.

Effect of pomegranate peel with/without autologous bone marrow on healing of acute cutaneous wounds in alloxan-induced diabetic rabbits

Background

Healing of bum wounds is commonly associated with many complications. Every year various new repair materials are developed and experimentally used for treating burn wounds. Humans with diabetes mellitus usually suffer from chronic wound healing. Vascular, neuropathic, immune function, and biochemical abnormalities each contribute to the altered tissue repair. One underlying factor that accompanies all diabetic ulcerations is poor vascular flow, a circumstance that impedes proper wound healing. Numerous studies have highlighted the importance of adequate vascular sufficiency and vessel proliferation in tissue repair and the lack thereof in diabetic wound healing. Other studies have looked at whether disarrayed capillary remodeling and maturation of vessels might play a role in impaired diabetic wound healing.

Aim

This investigation has been planned to report the influence of treatment with a mixture of both the powder of pomegranate peel (PP) accompanied with an autologous bone marrow (BM) on the cure of burn injuries in experimentally induced diabetic rabbits.

Methods

Alloxan monohydrate has been applied to create diabetes in 50 rabbits. Then in each rabbit, two deep second-degree burn wounds were experimentally created. The animals were then divided randomly into 5 treatment sections: non-treatment controls (C1), treated with an available commercial powder for wound (C2), treatment with powder of PP, treatment with alone BM, and the final group treated with PP powder with bone marrow (PPBM). The speed of wound closure and the histopathological changes during healing were measured. The levels of the biomarkers of rabbit platelet-derived growth factor AA (PDGF-AA) and rabbit protease-activated receptor 1 (PAR-1) were measured on days 0, 4, 8, and 12.

Results

Wound healing was markedly more rapid in all the treatment groups versus the control non-treated group. Interestingly, a rapid wound cure was significantly observed in the PPBM group versus the other treatment ones. The histological assessment clarified a significant elevation in the fibroblast and collagen scores in the PPBM group versus the other sections. In addition, there were significant increases in the serum levels of the biomarkers PDGF-AA and PAR-1 among groups.

Conclusion

Dependent on the results of current research, it can be concluded that both PP powder with BM PPBM significantly accelerate the healing process of burn wounds in experimentally induced diabetic rabbits.

Biomimetic Scaffolds for Regeneration of Temporomandibular Joint Disc: A Narrative Review

Defects and dysfunctions of temporomandibular joint (TMJ) disc are responsible for the majority of TMJ diseases. Current treatments in this matter are usually short-term and only palliative, thus an alternative treatment that offers long-lasting repair is in great demand. In recent years great attempts have been made to prepare an ideal scaffold, which best resembles the native TMJ disc in characteristics such as mechanical, physical and biological properties. This narrative review focuses on developments of the recent ten years in fabrication of scaffolds using decellularized tissues, natural and synthetic biomaterials for regeneration of TMJ disc and compared their properties. PubMed and Google Scholar databases were searched using the following keywords ("TMJ" OR "temporomandibular joint" OR "TMD" OR "temporomandibular disease") AND ("scaffold" OR "hydrogels"). Randomized controlled trials, randomized clinical trials, case-controls, case reports, and animal studies were included. Comments, systematic reviews, meta-analyses, and non-English papers were excluded. The study concluded that hybrid scaffolds have exhibited favorable cell attachment and proliferation. Synthetic scaffolds have shown promise in providing better control over structural properties; however, additional processes are often required to provide biomimetic cell signaling. While there is still much to learn about the ideal scaffold for TMJ disc regeneration, both natural and synthetic scaffolds have shown promise in achieving the functional, structural, biological, and mechanical properties of a native TMJ disc.

Non-Covalent Cross-Linking Hydrogel: A New Method for Visceral Hemostasis

Excessive blood loss could lead to pathological conditions such as tissue necrosis, organ failure, and death. The limitations of recently developed hemostatic approaches, such as their low mechanical strength, inadequate wet tissue adhesion, and weak hemostatic activity, pose challenges for their application in controlling visceral bleeding. In this study, a novel hydrogel (CT) made of collagen and tannic acid (TA) was proposed. By altering the proportions between the two materials, the mechanical properties, adhesion, and coagulation ability were evaluated. Compared to commercial hydrogels, this hydrogel has shown reduced blood loss and shorter hemostatic time in rat hepatic and cardiac bleeding models. This was explained by the hydrogel's natural hemostatic properties and the significant benefits of wound closure in a moist environment. Better biodegradability was achieved through the non-covalent connection between tannic acid and collagen, allowing for hemostasis without hindering subsequent tissue repair. Therefore, this hydrogel is a new method for visceral hemostasis that offers significant advantages in treating acute wounds and controlling major bleeding. And the production method is simple and efficient, which facilitates its translation to clinical applications.

Bioarchitectural Design of Bioactive Biopolymers: Structure-Function Paradigm for Diabetic Wound Healing

Chronic wounds such as diabetic ulcers are a major complication in diabetes caused by hyperglycemia, prolonged inflammation, high oxidative stress, and bacterial bioburden. Bioactive biopolymers have been found to have a biological response in wound tissue microenvironments and are used for developing advanced tissue engineering strategies to enhance wound healing. These biopolymers possess innate bioactivity and are biodegradable, with favourable mechanical properties. However, their bioactivity is highly dependent on their structural properties, which need to be carefully considered while developing wound healing strategies. Biopolymers such as alginate, chitosan, hyaluronic acid, and collagen have previously been used in wound healing solutions but the modulation of structural/physico-chemical properties for differential bioactivity have not been the prime focus. Factors such as molecular weight, degree of polymerization, amino acid sequences, and hierarchical structures can have a spectrum of immunomodulatory, anti-bacterial, and anti-oxidant properties that could determine the fate of the wound. The current narrative review addresses the structure-function relationship in bioactive biopolymers for promoting healing in chronic wounds with emphasis on diabetic ulcers. This review highlights the need for characterization of the biopolymers under research while designing biomaterials to maximize the inherent bioactive potency for better tissue regeneration outcomes, especially in the context of diabetic ulcers.

Human-Derived collagen hydrogel as an antibiotic vehicle for topical treatment of bacterial biofilms

The complexity of chronic wounds creates difficulty in effective treatments, leading to prolonged care and significant morbidity. Additionally, these wounds are incredibly prone to bacterial biofilm development, further complicating treatment. The current standard treatment of colonized superficial wounds, debridement with intermittent systemic antibiotics, can lead to systemic side-effects and often fails to directly target the bacterial biofilm. Furthermore, standard of care dressings do not directly provide adequate antimicrobial properties. This study aims to assess the capacity of human-derived collagen hydrogel to provide sustained antibiotic release to disrupt bacterial biofilms and decrease bacterial load while maintaining host cell viability and scaffold integrity. Human collagen harvested from flexor tendons underwent processing to yield a gellable liquid, and subsequently was combined with varying concentrations of gentamicin (50-500 mg/L) or clindamycin (10-100 mg/L). The elution kinetics of antibiotics from the hydrogel were analyzed using liquid chromatography-mass spectrometry. The gel was used to topically treat Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium perfringens in established Kirby-Bauer and Crystal Violet models to assess the efficacy of bacterial inhibition. 2D mammalian cell monolayers were topically treated, and cell death was quantified to assess cytotoxicity. Bacteria-enhanced in vitro scratch assays were treated with antibiotic-embedded hydrogel and imaged over time to assess cell death and mobility. Collagen hydrogel embedded with antibiotics (cHG+abx) demonstrated sustained antibiotic release for up to 48 hours with successful inhibition of both MRSA and C. perfringens biofilms, while remaining bioactive up to 72 hours. Administration of cHG+abx with antibiotic concentrations up to 100X minimum inhibitory concentration was found to be non-toxic and facilitated mammalian cell migration in an in vitro scratch model. Collagen hydrogel is a promising pharmaceutical delivery vehicle that allows for safe, precise bacterial targeting for effective bacterial inhibition in a pro-regenerative scaffold.

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

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

Layered Double Hydroxides: Recent Progress and Promising Perspectives Toward Biomedical Applications

Layered double hydroxides (LDHs) have been widely studied for biomedical applications due to their excellent properties, such as good biocompatibility, degradability, interlayer ion exchangeability, high loading capacity, pH-responsive release, and large specific surface area. Furthermore, the flexibility in the structural composition and ease of surface modification of LDHs makes it possible to develop specifically functionalized LDHs to meet the needs of different applications. In this review, the recent advances of LDHs for biomedical applications, which include LDH-based drug delivery systems, LDHs for cancer diagnosis and therapy, tissue engineering, coatings, functional membranes, and biosensors, are comprehensively discussed. From these various biomedical research fields, it can be seen that there is great potential and possibility for the use of LDHs in biomedical applications. However, at the same time, it must be recognized that the actual clinical translation of LDHs is still very limited. Therefore, the current limitations of related research on LDHs are discussed by combining limited examples of actual clinical translation with requirements for clinical translation of biomaterials. Finally, an outlook on future research related to LDHs is provided.

An Antioxidative and Active Shrinkage Hydrogel Integratedly Promotes Re-Epithelization and Skin Constriction for Enhancing Wound Closure

Delayed re-epithelization and weakened skin contractions are the two primary factors that hinder wound closure in large-scale acute or chronic wounds. However, effective strategies for targeting these two aspects concurrently are still lacking. Herein, an antioxidative active-shrinkage hydrogel (AHF@AS Gel) is constructed that can integratedly promote re-epithelization and skin constriction to accelerate large-scale acute and diabetic chronic wound closure. The AHF@AS Gel is encapsulated by antioxidative amino- and hydroxyl-modified C70 fullerene (AHF) and a thermosensitive active shrinkage hydrogel (AS Gel). Specifically, AHF relieves overactivated inflammation, prevents cellular apoptosis, and promotes fibroblast migration in vitro by reducing excessive reactive oxygen species (ROS). Notably, the AHF@AS Gel achieved ≈2.7-fold and ≈1.7-fold better re-epithelization in acute wounds and chronic diabetic wounds, respectively, significantly contributing to the promotion of wound closure. Using proteomic profiling and mechanistic studies, it is identified that the AHF@AS Gel efficiently promoted the transition of the inflammatory and proliferative phases to the remodeling phase. Notably, it is demonstrated that AS Gel alone activates the mechanosensitive epidermal growth factor receptor/Akt (EGFR/Akt) pathway and promotes cell proliferation. The antioxidative active shrinkage hydrogel offers a comprehensive strategy for acute wound and diabetic chronic wound closure via biochemistry regulation integrating with mechanical forces stimulation.

Interfacial water on collagen nanoribbons by 3D AFM

Collagen is the most abundant structural protein in mammals. Type I collagen in its fibril form has a characteristic pattern structure that alternates two regions called gap and overlap. The structure and properties of collagens are highly dependent on the water and mineral content of the environment. Here, we apply 3D AFM to characterize at angstrom-scale resolution the interfacial water structure of collagen nanoribbons. For a neutral tip, the interfacial water structure is characterized by the oscillation of the water particle density distribution with a value of 0.3 nm (hydration layers). The interfacial structure does not depend on the collagen region. For a negatively charged tip, the interfacial structure might depend on the collagen region. Hydration layers are observed in overlap regions, while in gap regions, the interfacial solvent structure is dominated by electrostatic interactions. These interactions generate interlayer distances of 0.2 nm.

Bioactive Dressing: A New Algorithm in Wound Healing

Wound management presents a significant global challenge, necessitating a comprehensive understanding of wound care products and clinical expertise in selecting dressings. Bioactive dressings (BD) represent a diverse category of dressings, capable of influencing wound healing through various mechanisms. These dressings, including honey, hyaluronic acid, collagen, alginates, and polymers enriched with polyhexamethylene biguanide, chitin, and chitosan derivatives, create a conducive environment for healing, promoting moisture balance, pH regulation, oxygen permeability, and fluid management. Interactive dressings further enhance targeted action by serving as substrates for bioactive agents. The continuous evolution of BDs, with new products introduced annually, underscores the need for updated knowledge in wound care. To facilitate dressing selection, a practical algorithm considers wound exudate, infection probability, and bleeding, guiding clinicians through the process. This algorithm aims to optimize wound care by ensuring the appropriate selection of BDs tailored to individual patient needs, ultimately improving outcomes in wound management.

Pharmaceutical Applications of Biomass Polymers: Review of Current Research and Perspectives

Polymers derived from natural biomass have emerged as a valuable resource in the field of biomedicine due to their versatility. Polysaccharides, peptides, proteins, and lignin have demonstrated promising results in various applications, including drug delivery design. However, several challenges need to be addressed to realize the full potential of these polymers. The current paper provides a comprehensive overview of the latest research and perspectives in this area, with a particular focus on developing effective methods and efficient drug delivery systems. This review aims to offer insights into the opportunities and challenges associated with the use of natural polymers in biomedicine and to provide a roadmap for future research in this field.

Precise healing of oral and maxillofacial wounds: tissue engineering strategies and their associated mechanisms

Precise healing of wounds in the oral and maxillofacial regions is usually achieved by targeting the entire healing process. The rich blood circulation in the oral and maxillofacial regions promotes the rapid healing of wounds through the action of various growth factors. Correspondingly, their tissue engineering can aid in preventing wound infections, accelerate angiogenesis, and enhance the proliferation and migration of tissue cells during wound healing. Recent years, have witnessed an increase in the number of researchers focusing on tissue engineering, particularly for precise wound healing. In this context, hydrogels, which possess a soft viscoelastic nature and demonstrate exceptional biocompatibility and biodegradability, have emerged as the current research hotspot. Additionally, nanofibers, films, and foam sponges have been explored as some of the most viable materials for wound healing, with noted advantages and drawbacks. Accordingly, future research is highly likely to explore the application of these materials harboring enhanced mechanical properties, reduced susceptibility to external mechanical disturbances, and commendable water absorption and non-expansion attributes, for superior wound healing.

Combined Amniotic Membrane and Self-Powered Electrical Stimulator Bioelectronic Dress Promotes Wound Healing

Human amniotic membranes (hAMs) are widely used as wound management biomaterials, especially as grafts for corneal reconstruction due to the structure of the extracellular matrix and excellent biological properties. However, their fragile nature and rapid degradation rate hinder widespread clinical use. In this work, we engineered a novel self-powered electronic dress (E-dress), combining the beneficial properties of an amniotic membrane and a flexible electrical electrode to enhance wound healing. The E-dress displayed a sustained discharge capacity, leading to increased epidermal growth factor (EGF) release from amniotic mesenchymal interstitial stem cells. Live/dead staining, CCK-8, and scratch-wound-closure assays were performed in vitro. Compared with amniotic membrane treatment alone, the E-dress promoted cell proliferation and migration of mouse fibroblast cells and lower cytotoxicity. In a mouse full-skin defect model, the E-dress achieved significantly accelerated wound closure. Histological analysis revealed that E-dress treatment promoted epithelialization and neovascularization in mouse skin. The E-dress exhibited a desirable flexibility that aligned with tissue organization and displayed maximum bioactivity within a short period to overcome rapid degradation, implying great potential for clinical applications.

Visualizing the global trends of peptides in wound healing through an in-depth bibliometric analysis

Wound healing is a complicated and multistage biological process for the repair of damaged/injured tissues, which requires intelligent designs to provide comprehensive and convenient treatment. Peptide-based wound dressings have received extensive attention for further development and application due to their excellent biocompatibility and multifunctionality. However, the current lack of intuitive analysis of the development trend and research hotspots of peptides applied in wound healing, as well as detailed elaboration of possible research hotspots, restricted obtaining a comprehensive understanding and development in this field. The present study analysed publications from the Web of Science (WOS) Core Collection database and visualized the hotspots and current trends of peptide research in wound healing. Data between January 1st, 2003, and December 31st, 2022, were collected and subjected to a bibliometric analysis. The countries, institutions, co-authorship, co-citation reference, and co-occurrence of keywords in this subject were examined using VOSviewer and CiteSpace. We provided an intuitive, timely, and logical overview of the development prospects and challenges of peptide application in wound healing and some solutions to the major obstacles, which will help researchers gain insights into the investigation of this promising field.

Efficacy of Topical Application of Chum Salmon (Oncorhynchus keta) Skin-derived Collagen Extracts in Improving Oral Traumatic Ulcer Healing

Background

Traumatic ulcer is a wound on the oral mucosa that often causes pain and impaired eating function. Healing of these wounds takes a long time and can interfere with an individual's daily activities. One therapeutic approach that is being developed is the use of topical application of chum salmon skin-derived collagen extract. Collagen is the main component of the extracellular matrix and plays a major role in wound healing. The skin of chum salmon (Oncorhynchus keta) contains collagen that is effective for the treatment of wounds.

Aim

The aim of this study was to evaluate the effectiveness of topical applications of chum salmon (O. keta) skin-derived collagen extracts in improving the healing of traumatic ulcers through analysis of neutrophil and macrophage numbers and collagen density.

Materials and Methods

Twenty-four male Wistar rats were randomly divided into four groups consisting of six rats each. The labial mucosa of the lower lips of the rats was injured with heated amalgam stoppers to create oral traumatic ulcers. Group 1 was a control group; in Groups 2, 3, and 4, 25%, 50%, and 75% of collagen extracts from chum salmon (O. keta) skin were applied topically once a day for 7 days, respectively. The neutrophil and macrophage numbers were observed by hematoxylin and eosin staining. Masson's Trichrome staining was used to analyze the collagen density. Data were analyzed using one-way analysis of variance and continued with post hoc least significant difference tests. Significance is considered if P < 0.05.

Results

The oral traumatic ulcers gradually healed until day 7. The number of neutrophils and macrophages was significantly decreased in the treatment groups, and collagen density was increased, compared to the control group (P < 0.05). The decrease of neutrophil and macrophage numbers occurred significantly with the increased collagen extract concentrations (P < 0.05). Collagen density also increased significantly with the increased collagen extract concentrations (P < 0.05).

Conclusion

Topical applications of chum salmon (O. keta) skin-derived collagen extracts accelerate the healing process of oral traumatic ulcers by decreasing neutrophil and macrophage numbers and increasing collagen density.

Fucoidan-coated cotton dressing functionalized with biomolecules capped silver nanoparticles (LB-Ag NPs-FN-OCG) for rapid healing therapy of infected wounds

The colonization of pathogenic microbes poses a significant clinical barrier that hinders the physiological wound-healing process. Addressing this challenge, we developed a novel wound dressing using a modified cotton gauze dressing coated with fucoidan and functionalized with silver nanoparticles (LB-Ag NPs-FN-OCG) for the rapid treatment of infected wounds. Firstly, phytochemical-capped LB-Ag NPs were synthesized and characterized using high performance liquid chromatography (HPLC), transmission electron microscopy (TEM), and zeta potential analysis. Secondly, different concentrations of LB-Ag NPs (0.1%-1%) were functionalized into FN-OCG to identify appropriate concentrations that were non-toxic with superior antibacterial activities. Screening assays, including antibacterial, hemolysis, chick chorioallantoic membrane (CAM) assay, and cytotoxicity assay, revealed that LB-Ag NPs (0.5%)-FN-OCG were non-toxic and demonstrated greater efficiency in inhibiting bacterial pathogens (Escherichia coli, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes) and promoting fibroblast cell (NIH3T3) migration. In vivo assays revealed that LB-Ag NPs (0.5%)-FN-OCG treatment exhibited excellent wound healing activity (99.73 ± 0.01%) compared to other treatments by inhibiting bacterial colonization, maintaining the blood parameters, developing granulation tissue, new blood vessels, and collagen deposition. Overall, this study highlights that LB-Ag NPs (0.5%)-FN-OCG serve as a antibacterial wound dressing for infected wound healing applications.

Laminin mimetic angiogenic and collagen peptide hydrogel for enhance dermal wound healing

Laminins are essential in basement membrane architecture and critical in re-epithelialization and angiogenesis. These processes and collagen deposition are vital in skin wound healing. The role of angiogenic peptides in accelerating the wound-healing process has been known. The bioactive peptides could be a potential approach due to their similar effects as growth factors and inherent biocompatible and biodegradable nature with lower cost. They can also recognize ligand-receptor interaction and mimic the extracellular matrix. Here, we report novel angiogenic DYVRLAI, CDYVRLAI, angiogenic-collagen PGPIKVAV, and Ac-PGPIKVAV peptides conjugated sodium carboxymethyl cellulose hydrogel, which was designed from laminin. The designed peptide exhibits a better binding with the α3β1, αvβ3, and α5β1 integrins and CXCR2 receptor, indicating their angiogenic and collagen binding efficiency. The peptides were evaluated to stimulate wound healing in full-thickness excision wounds in normal and diabetic mice (type II). They demonstrated their efficacy in terms of angiogenesis (CD31), re-epithelialization through regeneration of the epidermis (H&E), and collagen deposition (MT). The synthesized peptide hydrogel (DYVRLAI and CDYVRLAI) showed enhanced wound contraction up to 10.1 % and 12.3 % on day 7th compared to standard becaplermin gel (49 %) in a normal wound model. The encouraging results were also observed with the diabetic model, where these peptides showed a significant decrease of 5.20 and 5.17 % in wound size on day 10th compared to the commercial gel (9.27 %). These outcomes signify that the modified angiogenic peptide is a cost effective, novel peptide motif to promote dermal wound healing in both models.

Use of collagen and auricular cartilage in bioengineering: scaffolds for tissue regeneration

The aim of this study was the development of collagen and collagen/auricular cartilage scaffolds for application in dermal regeneration. Collagen was obtained from bovine tendon by a 72 h-long treatment, while bovine auricular cartilage was treated for 24 h and divided into two parts, external (perichondrium, E) and internal (elastic cartilage, I). The scaffolds were prepared by mixing collagen (C) with the internal part (CI) or the external part (CE) in a 3:1 ratio. Differential scanning calorimetry, scanning electron microscopy (SEM) analysis, microcomputed tomography imaging (micro-CT) and swelling degree were used to characterize the scaffolds. Cytotoxicity, cell adhesion, and cell proliferation assays were performed using the cell line NIH/3T3. All samples presented a similar denaturation temperature (Td) around 48 °C, while CE presented a second Td at 51.2 °C. SEM micrographs showed superficial pores in all scaffolds and micro-CT exhibited interconnected pore spaces with porosity above 60% (sizes between 47 and 149 µm). The order of swelling was CE < CI < C and the scaffolds did not present cytotoxicity, showing attachment rates above 75%-all samples showed a similar pattern of proliferation until 168 h, whereas CI tended to decrease after this time. The scaffolds were easily obtained, biocompatible and had adequate morphology for cell growth. All samples showed high adhesion, whereas collagen-only and collagen/external part scaffolds presented a better cell proliferation rate and would be indicated for possible use in dermal regeneration.

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.

CSMed® wound dressing for prophylaxis and management of radiation dermatitis in breast and head-neck cancer patients: a single hospital prospective clinical trial

PURPOSE

CSMed® wound dressing, a dressing with various herb extracts, was tested for its therapeutic effect in radiation dermatitis of breast and head-and-neck cancer patients.

METHODS

This study included 20 breast cancer patients and 10 head-and-neck cancer patients. Half of the irradiated area was covered with CSMed® and the other half was under routine treatment. The severity of radiation dermatitis was evaluated with radiation therapy oncology group (RTOG) grade throughout the treatment and the follow-up period. The RTOG grade between the dressed and undressed area were compared to illustrate the therapeutic effect of CSMed® dressing.

RESULTS

The results showed that CSMed® dressed area had significant lower RTOG score at 3-7 weeks and final record during the treatment, and 1-3 weeks during follow-up than undressed area.

CONCLUSIONS

This indicated that CSMed® can delay the onset, reduce the severity, and enhance healing of radiation dermatitis. CSMed® can be used for prophylaxis and management of radiation dermatitis.

Development of collagenous scaffolds for wound healing: characterization and in vivo analysis

The development of wound dressings from biomaterials has been the subject of research due to their unique structural and functional characteristics. Proteins from animal origin, such as collagen and chitosan, act as promising materials for applications in injuries and chronic wounds, functioning as a repairing agent. This study aims to evaluate in vitro effects of scaffolds with different formulations containing bioactive compounds such as collagen, chitosan, N-acetylcysteine (NAC) and ε-poly-lysine (ε-PL). We manufactured a scaffold made of a collagen hydrogel bioconjugated with chitosan by crosslinking and addition of NAC and ε-PL. Cell viability was verified by resazurin and live/dead assays and the ultrastructure of biomaterials was evaluated by SEM. Antimicrobial sensitivity was assessed by antibiogram. The healing potential of the biomaterial was evaluated in vivo, in a model of healing of excisional wounds in mice. On the 7th day after the injury, the wounds and surrounding skin were processed for evaluation of biochemical and histological parameters associated with the inflammatory process. The results showed great cell viability and increase in porosity after crosslinking while antimicrobial action was observed in scaffolds containing NAC and ε-PL. Chitosan scaffolds bioconjugated with NAC/ε-PL showed improvement in tissue healing, with reduced lesion size and reduced inflammation. It is concluded that scaffolds crosslinked with chitosan-NAC-ε-PL have the desirable characteristics for tissue repair at low cost and could be considered promising biomaterials in the practice of regenerative medicine.

Recent advances in production of sustainable and biodegradable polymers from agro-food waste: Applications in tissue engineering and regenerative medicines

Agro-food waste is a rich source of biopolymers such as cellulose, chitin, and starch, which have been shown to possess excellent biocompatibility, biodegradability, and low toxicity. These properties make biopolymers from agro-food waste for its application in tissue engineering and regenerative medicine. Thus, this review highlighted the properties, processing methods, and applications of biopolymers derived from various agro-food waste sources. We also highlight recent advances in the development of biopolymers from agro-food waste and their potential for future tissue engineering and regenerative medicine applications, including drug delivery, wound healing, tissue engineering, biodegradable packaging, excipients, dental applications, diagnostic tools, and medical implants. Additionally, it explores the challenges, prospects, and future directions in this rapidly evolving field. The review showed the evolution of production techniques for transforming agro-food waste into valuable biopolymers. However, these biopolymers serving as the cornerstone in scaffold development and drug delivery systems. With their role in wound dressings, cell encapsulation, and regenerative therapies, biopolymers promote efficient wound healing, cell transplantation, and diverse regenerative treatments. Biopolymers support various regenerative treatments, including cartilage and bone regeneration, nerve repair, and organ transplantation. Overall, this review concluded the potential of biopolymers from agro-food waste as a sustainable and cost-effective solution in tissue engineering and regenerative medicine, offering innovative solutions for medical treatments and promoting the advancement of these fields.

Engineering periodontal tissue interfaces using multiphasic scaffolds and membranes for guided bone and tissue regeneration

Periodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed.

Selection of collagen IV fragments forming the outer sphere of the native protein: Assessment of biological activity for regenerative medicine

The aim of this research was to select the fragments that make up the outer layer of the collagen IV (COL4A6) protein and to assess their potential usefulness for regenerative medicine. It was expected that because protein-protein interactions take place via contact between external domains, the set of peptides forming the outer sphere of collagen IV will determine its interaction with other proteins. Cellulose-immobilized protein fragment libraries treated with polyclonal anti-collagen IV antibodies were used to select the peptides forming the outer sphere of collagen IV. In the first test, 33 peptides that strongly interacted with the polyclonal anti-collagen IV antibodies were selected from a library of non-overlapping fragments of collagen IV. The selected fragments of collagen IV (cleaved from the cellulose matrix) were tested for their cytotoxicity, their effects on cell viability and proliferation, and their impact on the formation of reactive oxygen species (ROS). The studies used RAW 264.7 mouse macrophage cells and Hs 680.Tr human fibroblasts. PrestoBlue, ToxiLight™, and ToxiLight 100% Lysis Control assays were conducted. The viability of fibroblasts cultured with the addition of increasing concentrations of the peptide mix did not show statistically significant differences from the control. Fragments 161-170, 221-230, 721-730, 1331-1340, 1521-1530, and 1661-1670 of COL4A6 were examined for cytotoxicity against BJ normal human foreskin fibroblasts. None of the collagen fragments were found to be cytotoxic. Further research is underway on the potential uses of collagen IV fragments in regenerative medicine.

A Systematic Review of Fish-Based Biomaterial on Wound Healing and Anti-Inflammatory Processes

Objective: To conduct a systematic literature review to study the effects of fish-based biomaterials on wound healing in both in vivo and in vitro animal models. Approach: This review covers the study reported in different articles between 2016 and August 2022 concentrating mainly on the cytotoxicity evaluation of different fish-based biomaterials on inflammation, reepithelialization and wound healing. Significance: This review shows considerable amount of research work carried out with fish-based biomaterials and collagen for treating burn wounds. Surprisingly there are only a few commercial products developed so far in this particular regard for surgical purpose and therefore, there is a way out and need for developing medical support product from fish-based biomaterials to treat and cure wounds. Recent Advances: Three-dimensional skin bioprinting technique is a large-scale solution for severe burn wounds that requires collagen as a raw material for printing, wherein fish collagen can be used in place of bovine and porcine, as it is biocompatible, promotes cell proliferation, adhesion, and migration, and degrades enzymatically. In the recent times, there are a few fish-based surgical products that have been formulated by Kerecis in United States. Critical Issues: The different fish-based biomaterial products are all mere supplements taken in orally as food or supplements till date and there is no proper proven medications that has been formulated so far in the field of wound healing and inflammation based on fish biomaterials except the surgical products that can be finger counted. Future Directions: Fish-based biomaterials are known for the medicinal properties that are used throughout the world and further investigations should be carried out to understand the actual physiochemical properties of its derivatives for the discovery of novel products and drugs.

An injectable collagen peptide-based hydrogel with desirable antibacterial, self-healing and wound-healing properties based on multiple-dynamic crosslinking

Conventional collagen-based hydrogels as wound dressing materials are usually lack of antibacterial activity and easily broken when encountering external forces. In this work, we developed a collagen peptide-based hydrogel as a wound dressing, which was composed of adipic acid dihydrazide functionalized collagen peptide (Col-ADH), oxidized dextran (ODex), polyvinyl alcohol (PVA) and borax via multiple-dynamic reversible bonds (acylhydrazone, amine, borate ester and hydrogen bonds). The injectable hydrogel exhibited satisfactory self-healing ability, antibacterial activity, mechanical strength, as well as good biocompatibility and biodegradability. In vivo experiments demonstrated the rapid hemostasis, accelerated cell migration, and promoted wound healing capacities of the hydrogel. These results indicate that the multifunctional collagen peptide-based hydrogel has great potentials in the field of wound dressings.

Degradable Polymeric Bio(nano)materials and Their Biomedical Applications: A Comprehensive Overview and Recent Updates

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

Exploring the potential of polysaccharide-based hybrid hydrogel systems for their biomedical and therapeutic applications: A review

Hydrogels are a versatile category of biomaterials that have been widely applied in the fields of biomedicine for the last several decades. The three-dimensional polymeric crosslinked hydrophilic structures of the hydrogel can proficiently hold drugs, nanoparticles, and cells, making them a potential delivery system. However, disadvantages like low mechanical strength, poor biocompatibility, and unusual in-vivo biodegradation are associated with conventional hydrogels. To overcome these hurdles, hybrid hydrogels are designed using two or more structurally different polymeric units. Polysaccharides, characterized by their innate biocompatibility, biodegradability, and abundance, establish an ideal foundation for the development of these hybrid hydrogels. This review aims to discuss the studies that have utilized naturally occurring polysaccharides to prepare hybrid systems, which were aimed for various biomedical applications such as tissue engineering, bone and cartilage regeneration, wound healing, skin cancer treatment, antimicrobial therapy, osteoarthritis treatment, and drug delivery. Furthermore, this review extensively examines the properties of the employed polysaccharides within hydrogel matrices, emphasizing the advantageous characteristics that make them a preferred choice. Furthermore, the challenges associated with the commercial implementation of these systems are explored alongside an assessment of the current patent landscape.

On the effect of pepsin incubation on type I collagen from horse tendon: Fine tuning of its physico-chemical and rheological properties

Type I collagen is commonly recognized as the gold standard biomaterial for the manufacturing of medical devices for health-care related applications. In recent years, with the final aim of developing scaffolds with optimal bioactivity, even more studies focused on the influence of processing parameters on collagen properties, since processing can strongly affect the architecture of collagen at various length scales and, consequently, scaffolds macroscopic performances. The ability to finely tune scaffold properties in order to closely mimic the tissues' hierarchical features, preserving collagen's natural conformation, is actually of great interest. In this work, the effect of the pepsin-based extraction step on the material final properties was investigated. Thus, the physico-chemical properties of fibrillar type I collagens upon being extracted under various conditions were analyzed in depth. Correlations of collagen structure at the supramolecular scale with its microstructural properties were done, confirming the possibility of tuning rheological, viscoelastic and degradation properties of fibrillar type I collagen.