Tough and biodegradable polyurethane-curcumin composited hydrogel with antioxidant, antibacterial and antitumor properties

Recent Advances in the Degradability and Applications of Tissue Adhesives Based on Biodegradable Polymers

In clinical practice, tissue adhesives have emerged as an alternative tool for wound treatments due to their advantages in ease of use, rapid application, less pain, and minimal tissue damage. Since most tissue adhesives are designed for internal use or wound treatments, the biodegradation of adhesives is important. To endow tissue adhesives with biodegradability, in the past few decades, various biodegradable polymers, either natural polymers (such as chitosan, hyaluronic acid, gelatin, chondroitin sulfate, starch, sodium alginate, glucans, pectin, functional proteins, and peptides) or synthetic polymers (such as poly(lactic acid), polyurethanes, polycaprolactone, and poly(lactic-co-glycolic acid)), have been utilized to develop novel biodegradable tissue adhesives. Incorporated biodegradable polymers are degraded in vivo with time under specific conditions, leading to the destruction of the structure and the further degradation of tissue adhesives. In this review, we first summarize the strategies of utilizing biodegradable polymers to develop tissue adhesives. Furthermore, we provide a symmetric overview of the biodegradable polymers used for tissue adhesives, with a specific focus on the degradability and applications of these tissue adhesives. Additionally, the challenges and perspectives of biodegradable polymer-based tissue adhesives are discussed. We expect that this review can provide new inspirations for the design of novel biodegradable tissue adhesives for biomedical applications.

Curcumin-loaded mesoporous polydopamine nanoparticles modified by quaternized chitosan against bacterial infection through synergistic effect

Clinically, open wounds caused by accidental trauma and surgical lesion resection are easily infected by external bacteria, hindering wound healing. Antibacterial photodynamic therapy has become a promising treatment strategy for wound infection. In this study, a novel antibacterial nanocomposite material (QMC NPs) was synthesized by curcumin, quaternized chitosan and mesoporous polydopamine nanoparticles. The results showed that 150 μg/mL QMC NPs had good biocompatibility and exerted excellent antibacterial activity against Staphylococcus aureus and Escherichia coli after blue laser irradiation (450 nm, 1 W/cm2). In vivo, QMC NPs effectively treated bacterial infection and accelerated the healing of infected wounds in mice.

A polyurethane-based hydrophilic elastomer with multi-biological functions for small-diameter vascular grafts

Thrombosis and intimal hyperplasia (IH) are two major problems faced by the small-diameter vascular grafts. Mimicking the native endothelium and physiological elasticity of blood vessels is considered an ideal strategy. Polyurethane (PU) is suitable for vascular grafts in mechanics because of its molecular designability and elasticity; however, it generally lacks the endothelium-like biofunctions and hydrophilicity. To solve this contradiction, a hydrophilic PU elastomer is developed by crosslinking the hydrophobic hard-segment chains containing diselenide with diaminopyrimidine-capped polyethylene glycol (PEG). In this network, the hydrophobic aggregation occurs underwater due to the uninterrupted hard-segment chains, leading to a significant self-enhancement in mechanics, which can be tailored to the elasticity similar to natural vessels by adjusting the crosslinking density. A series of in vitro studies confirm that the hydrophilicity of PEG and biological activities of aminopyrimidine and diselenide give the PU multi-biological functions similar to the native endothelium, including stable catalytic release of nitric oxide (NO) in the physiological level; anti-adhesion and anti-activation of platelets; inhibition of migration, adhesion, and proliferation of smooth muscle cells (SMCs); and antibacterial effect. In vivo studies further prove the good histocompatibility with both significant reduction in immune response and calcium deposition. STATEMENT OF SIGNIFICANCE: Constructing small-diameter vascular grafts similar to the natural vessels is considered an ideal method to solve the restenosis caused by thrombosis and intimal hyperplasia (IH). Because of the long-term stability, bulk modification is more suitable for implanted materials, however, how to achieve the biofunctions, hydrophilicity, and elasticity simultaneously is still a big challenge. In this work, a kind of polyurethane-based elastomer has been designed and prepared by crosslinking the functional long hard-segment chains with PEG soft segments. The underwater elasticity based on hydration-induced stiffening and the multi-biological functions similar to the native endothelium are compatible with natural vessels. Both in vitro and in vivo experiments demonstrate the potential of this PU as small-diameter vascular grafts.

Multifunctional gelatin nanoparticle stabilized-Pickering emulsion hydrogel based on dextran and amikacin with controlled drug release and enhanced antibacterial capability for promoting infected wound healing

Plant essential oils possess broad-spectral antimicrobial property, but the applications are impeded by their insolubility in water, extreme volatility, and strong irritation. Nanoparticle-stabilized emulsion (Pickering emulsion) gels are colloidal systems with ability to accommodate two immiscible phases in one system. The thick adsorption nanoparticle layers and the cross-linked networks in continuous phase could provide protective barriers for antibacterial oil and achieve on-demand controlled release. An emulsion hydrogel templated from gelatin nanoparticle-stabilized emulsion is one-pot constructed by conducting a tunable cross-linking process between oxidized dextran (Odex) and amikacin in the continuous phase and concomitantly trapping tea tree essential oil (TO) droplets in the three-dimensional network. The resulted emulsion hydrogel presents tunable gelation time, adequate mechanical strength, fascinating injectability, and self-healing capability. It is pH-responsiveness and presents controlled release of amikacin and TO, exhibiting a long-term bacteriostasis of 144 h. The emulsion hydrogel facilitates the outstanding wound healing efficiency in 14 days (95.2 ± 0.8 % of wound closure), accompanied with enhanced collagen deposition and angiogenic activities. The incorporation of TO into emulsion hydrogel system reduced its irritation and improved its biosafety, showing potential application in bacteria inhibition even as implants in vivo.

A novel designed nanofibrous mat based on hydroxypropyl methyl cellulose incorporating mango peel extract for potential use in wound care system

Skin tissue is damaged by factors such as burns, physical injuries and diseases namely diabetes. Infection and non-healing of burn wounds and lack of angiogenesis in diabetic wounds lead to extensive injuries and death. Therefore, the design of wound dressings with antibacterial and restorative capabilities is very important. In this study, nanofibers (NFs) including polyurethane (PU) and hydroxypropyl methyl cellulose (HPMC) were prepared with different ratios and Mango peel extract (MPE) loaded into NFs by electrospinning method. The morphology, chemical structure, porosity, degradation, water vapor permeability, mechanical properties, wettability, antioxidant activity and some cell studies and evaluation of their antibacterial properties were investigated. The optimal mat (PU90/HPMC10) had a defect-free morphology with homogeneous NFs. Furthermore, it showed improved biodegradability, water vapor permeability and porosity compared to other Mats. All NFs were non-toxic with hydrophilic behavior in the cellular environment and had acceptable hemocompatibility. The PU90/HPMC10/20 % optimal scaffold had significantly higher cell viability and proliferation than other samples and also had a higher antibacterial ability against pathogenic bacteria S. aureus (17 mm) and E. coli (11 mm). All these findings confirm that the produced NF mats, especially those loaded with MPE, have a high potential to be used as an effective wound dressing.

Synthesis of aminolyzed gelatin-mediated chitosan as pH-responsive drug-carrying porous scaffolds

Bio-based drug delivery devices have gained enormous interest in the biomedical field due to their biocompatible attributes. Extensive research is being conducted on chitosan-based devices for drug delivery applications. Chitosan being hydrophobic under neutral conditions makes it difficult to interact with a polar drug of curcumin. We tended to make it polar through sol-gel synthesis and modification via PEGylation, alkaline hydrolysis, and aminolysis. Such alterations could make the chitosan-based scaffolds porous, hydrophilic, amino-functionalized, and pH-responsive. The ninhydrin assay confirmed that a successful aminolysis occurred, and the chemical interaction among the precursors was explained under infrared spectroscopy. The scanning morphology of the optimum aminolyzed membrane appeared to be porous with an average pore size of 320 ± 20 nm. The aminolyzed chitosan membrane was found thermally stable up to 310 °C, hydrophilic with a water contact angle of 23.4°, moderate flowablity, and porous (97 ± 5 %, w/w) against ethanol. The curcumin-loaded chitosan membrane expressed the UV-protection behavior of 99 %. The curcumin-loading and release phenomena were found pH-responsive. The curcumin release results were evaluated through specific kinetic models. This study could be the first report on the amphiphilic, porous, and swellable drug-loaded gelatin/chitosan membrane with pH-responsive loading and release of curcumin for potential drug delivery applications.

Immune-microenvironment modulatory polyurethane-hyaluronic acid hybrid hydrogel scaffolds for diabetic wound treatment

The healing of wounds in diabetic patients is a huge challenge issue in clinical medicine due to the disordered immune. Recruiting endogenous cells to play a role in the early stage and timely reducing inflammation to promote healing in the middle or late of injuring are both prerequisites for effective treatment. Here, inspired by natural extracellular matrix, three-dimensional porous polyurethane-hyaluronic acid hybrid hydrogel scaffolds (PUHA) were prepared to repair diabetic wound through activate cell immunity by moderate foreign body reaction, provide cell adhesion growth extracellular matrix of hyaluronic acid (HA) and exhibit anti-inflammatory effect of polyurethane (PU). The interaction between PU and HA alters the compact PU hydrogel into macroporous PUHA hydrogel scaffolds with super-swelling, elastic mechanical properties, and controllable degradation, which are suitable for endogenous cells infiltration, growth and immune activation. Additionally, incorporating with RGD, PUHA hydrogel scaffolds with bioactive physicochemical features can evidently reduce the inflammation and modulate the polarization of macrophage apparently both in vitro and in vivo, mainly through downregulation of cytokine-cytokine receptor interaction genes, leading to reprogramming immune-microenvironment and rapid diabetic wound healing. This method of gathering cells initially and intervening immune-microenvironment in time provides an expected way to design biomaterials for chronic wound healing.

Structure Property Relationship of Micellar Waterborne Poly(Urethane-Urea): Tunable Mechanical Properties and Controlled Release Profiles with Amphiphilic Triblock Copolymers

Waterborne polyurethane (WPU) has attracted significant interest as a promising alternative to solvent-based polyurethane (SPU) due to its positive impact on safety and sustainability. However, significant limitations of WPU, such as its weaker mechanical strength, limit its ability to replace SPU. Triblock amphiphilic diols are promising materials to enhance the performance of WPU due to their well-defined hydrophobic-hydrophilic structures. Yet, our understanding of the relationship between the hydrophobic-hydrophilic arrangements of triblock amphiphilic diols and the physical properties of WPU remains limited. In this study, we show that by controlling the micellar structure of WPU in aqueous solution via the introduction of triblock amphiphilic diols, the postcuring efficiency and the resulting mechanical strength of WPU can be significantly enhanced. Small-angle neutron scattering confirmed the microstructure and spatial distribution of hydrophilic and hydrophobic segments in the engineered WPU micelles. In addition, we show that the control of the WPU micellar structure through triblock amphiphilic diols renders WPU attractive in the applications of controlled release, such as drug delivery. Here, curcumin was used as a model hydrophobic drug, and the drug release behavior from WPU-micellar-based drug delivery systems was characterized. It was found that curcumin-loaded WPU drug delivery systems were highly biocompatible and exhibited antibacterial properties in vitro. Furthermore, the sustained release profile of the drug was found to be dependent on the structure of the triblock amphiphilic diols, suggesting the possibility of controlling the drug release profile via the selection of triblock amphiphilic diols. This work shows that by shedding light on the structure-property relationship of triblock amphiphilic diol-containing WPU micelles, we may enhance the applicability of WPU systems and move closer to realizing their promising potential in real-life applications.

Next-Generation Hydrogels as Biomaterials for Biomedical Applications: Exploring the Role of Curcumin

Since the first report on the pharmacological activity of curcumin in 1949, enormous amounts of research have reported diverse activities for this natural polyphenol found in the dietary spice turmeric. However, curcumin has not yet been used for human application as an approved drug. The clinical translation of curcumin has been hampered due to its low solubility and bioavailability. The improvement in bioavailability and solubility of curcumin can be achieved by its formulation using drug delivery systems. Hydrogels with their biocompatibility and low toxicity effects have shown a substantial impact on the successful formulation of hydrophobic drugs for human clinical trials. This review focuses on hydrogel-based delivery systems for curcumin and describes its applications as anti-cancer as well as wound healing agents.

Preparation and characterization of curcumin/chitosan conjugate as an efficient photodynamic antibacterial agent

Curcumin (Cur) is a natural pigment with excellent biological activity. The poor stability and insolubility of Cur in water severely limit its application. Therefore, to overcome these dilemmas which are big hindrances in their application, a novel derivative (COCS-Cur) was prepared by the esterification reaction of carboxylated chitosan (COCS) and Cur. The structure and properties of conjugate were determined through a series of characterizations. The derivatives had excellent solubility as well as stability. In addition, antioxidant and photodynamic antibacterial experiments proved that COCS-Cur had the excellent free radical scavenging ability and photodynamic antibacterial activity. The derivatives presented a better antibacterial effect on Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli). Noteworthy, the COCS-Cur derivatives showed no obvious toxicity which makes them a stronger contender and potential antimicrobial agent or functional nutrient for application in the food industry.

Construction of an antibacterial hydrogel based on diammonium glycyrrhizinate and gallic acid for bacterial- infected wound healing

The current antibacterial wound dressings with antibiotic substances or metal bactericidal agents may lead to severe multidrug resistance and poor biocompatibilities. Herein, we report an inherent antibacterial hydrogel constructed by only two naturally small molecules gallic acid (GA) and diammonium glycyrrhizinate (DG) for promoting Staphylococcus aureus (S. aureus)-infected wound healing. The resultant GAD hydrogel can be fabricated by co-assembly of these two materials through simple steps. Thanks to the incorporation of GA and DG, GAD hydrogel enabled a strong mechanical performance and great self-healing property with a sustained-release of drugs into skin wounds. Moreover, the cell viability assays showed that GAD hydrogel had good cytocompatibility by promoting cell proliferation and migration. In addition, GAD hydrogel had broad antibacterial efficiency against both Gram-positive and Gram-negative bacteria. Taken together, GAD hydrogel is a promising dressing to accelerate bacterial-infected wound healing through reconstructing an intact and thick epidermis without antibiotics or cytokines.

Bio-macromolecular design roadmap towards tough bioadhesives

Emerging sutureless wound-closure techniques have led to paradigm shifts in wound management. State-of-the-art biomaterials offer biocompatible and biodegradable platforms enabling high cohesion (toughness) and adhesion for rapid bleeding control as well as robust attachment of implantable devices. Tough bioadhesion stems from the synergistic contributions of cohesive and adhesive interactions. This Review provides a biomacromolecular design roadmap for the development of tough adhesive surgical sealants. We discuss a library of materials and methods to introduce toughness and adhesion to biomaterials. Intrinsically tough and elastic polymers are leveraged primarily by introducing strong but dynamic inter- and intramolecular interactions either through polymer chain design or using crosslink regulating additives. In addition, many efforts have been made to promote underwater adhesion via covalent/noncovalent bonds, or through micro/macro-interlock mechanisms at the tissue interfaces. The materials settings and functional additives for this purpose and the related characterization methods are reviewed. Measurements and reporting needs for fair comparisons of different materials and their properties are discussed. Finally, future directions and further research opportunities for developing tough bioadhesive surgical sealants are highlighted.

The Importance of Antioxidant Biomaterials in Human Health and Technological Innovation: A Review

Biomaterials come from natural sources such as animals, plants, fungi, algae, and bacteria, composed mainly of protein, lipid, and carbohydrate molecules. The great diversity of biomaterials makes these compounds promising for developing new products for technological applications. In this sense, antioxidant biomaterials have been developed to exert biological and active functions in the human body and industrial formulations. Furthermore, antioxidant biomaterials come from natural sources, whose components can inhibit reactive oxygen species (ROS). Thus, these materials incorporated with antioxidants, mainly from plant sources, have important effects, such as anti-inflammatory, wound healing, antitumor, and anti-aging, in addition to increasing the shelf-life of products. Aiming at the importance of antioxidant biomaterials in different technological segments as biodegradable, economic, and promising sources, this review presents the main available biomaterials, antioxidant sources, and assigned biological activities. In addition, potential applications in the biomedical and industrial fields are described with a focus on innovative publications found in the literature in the last five years.

Hydrogel Combined with Phototherapy in Wound Healing

Wound healing is a complex biological process that involves tissue regeneration. Traditional wound dressings are dry, cannot provide a moist environment for wound healing, and do not have high antibacterial properties. Hydrogels, which are capable of retaining large amounts of water, can create a moist healing environment. Currently, phototherapies have exhibited a high potential for the treatment of bacterial infections. Therefore, combining hydrogels with phototherapy can adequately overcome the shortcomings of traditional wound treatment methods and show great potential for wound healing owing to their high efficiency, low irritation, and good antibacterial performance. In this review, the application of hydrogels combined with phototherapy in wound healing is summarized. First, the basic principles of photodynamic therapy and photothermal therapy are briefly introduced. In addition, the progress of the application of hydrogel combined with phototherapy in wound healing is systematically investigated. Finally, the challenges and prospects of combining hydrogel with phototherapy in wound healing are discussed.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Fabrication of Curcumin@Ag Loaded Core/Shell Nanofiber Membrane and its Synergistic Antibacterial Properties

The core/shell structure nanofiber membrane loaded with curcumin and silver nanoparticles was prepared by coaxial electrospinning technology, which is a high-efficiency combined antibacterial material composed of photodynamic antibacterial agent and metal nanoparticle. As a photosensitizer, curcumin could generate singlet oxygen under laser irradiation. Silver nanoparticles have antibacterial properties, and could also enhance the singlet oxygen production of curcumin due to the metal-enhanced singlet oxygen effect, thereby producing a synergistic antibacterial effect. Compared with the antibacterial rate of uniaxial curcumin fiber membrane (45.65%) and uniaxial silver nanoparticle-loaded fiber membrane (66.96%), the antibacterial rate of curcumin@Ag core/shell structure fiber membrane against Staphylococcus aureus is as high as 93.04%. In addition, the antibacterial experiments show that the core/shell fiber membrane also has excellent antibacterial effects on Escherichia coli.

A bioinspired Janus polyurethane membrane for potential periodontal tissue regeneration

Guided tissue regeneration (GTR) is the main therapeutic method for periodontal tissue regeneration. The key to the GTR strategy is the membrane which can assist the reconstruction of bone tissue in the periodontal defect and prevent the migration of epithelium and fibroblasts to the defect. However, the existing periodontal membrane cannot effectively promote periodontal tissue regeneration due to the limited bioactivity and physicochemical function. Here, we developed a bioinspired degradable polyurethane membrane with Janus surface morphology by integrating bioactive dopamine (DA) and an antibacterial Gemini quaternary ammonium salt (QAS). The Janus surface of the membrane is fabricated through spontaneous microphase separation, resulting from the different migration of functional segments between the air-contact upper surface with enriched antibacterial QAS and the substrate-contact bottom with enriched bioactive DA. The smooth surface of the upper membrane used to face the soft tissues can reduce cell adhesion to suppress the migration of fibroblasts, while the rough surface with a topological micro-pit structure of the bottom side facing the bone has excellent function of autonomic mineralization and cell adhesion to promote bone tissue reconstruction. In addition, the membrane containing the antibacterial QAS shows excellent antibacterial effect on common oral pathogens, such as S. aureus and S. mutans. Moreover, the specific dopamine group also endows the membrane with excellent antioxidant efficiency. In vivo research shows that this Janus polyurethane membrane can effectively promote periodontal tissue regeneration in a rat periodontal defect model. Combined with its excellent mechanical properties and biocompatibility, the polyurethane membrane is a promising material for potential periodontal tissue regeneration.

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

Antimicrobial photodynamic therapy (aPDT) has become a fundamental tool in modern therapeutics, notably due to the expanding versatility of photosensitizers (PSs) and the numerous possibilities to combine aPDT with other antimicrobial treatments to combat localized infections. After revisiting the basic principles of aPDT, this review first highlights the current state of the art of curative or preventive aPDT applications with relevant clinical trials. In addition, the most recent developments in photochemistry and photophysics as well as advanced carrier systems in the context of aPDT are provided, with a focus on the latest generations of efficient and versatile PSs and the progress towards hybrid-multicomponent systems. In particular, deeper insight into combinatory aPDT approaches is afforded, involving non-radiative or other light-based modalities. Selected aPDT perspectives are outlined, pointing out new strategies to target and treat microorganisms. Finally, the review works out the evolution of the conceptually simple PDT methodology towards a much more sophisticated, integrated, and innovative technology as an important element of potent antimicrobial strategies.

Hydrogel Preparation Methods and Biomaterials for Wound Dressing

Wounds have become one of the causes of death worldwide. The metabolic disorder of the wound microenvironment can lead to a series of serious symptoms, especially chronic wounds that bring great pain to patients, and there is currently no effective and widely used wound dressing. Therefore, it is important to develop new multifunctional wound dressings. Hydrogel is an ideal dressing candidate because of its 3D structure, good permeability, excellent biocompatibility, and ability to provide a moist environment for wound repair, which overcomes the shortcomings of traditional dressings. This article first briefly introduces the skin wound healing process, then the preparation methods of hydrogel dressings and the characteristics of hydrogel wound dressings made of natural biomaterials and synthetic materials are introduced. Finally, the development prospects and challenges of hydrogel wound dressings are discussed.

Alginate Bioconjugate and Graphene Oxide in Multifunctional Hydrogels for Versatile Biomedical Applications

In this work, we combined electrically-conductive graphene oxide and a sodium alginate-caffeic acid conjugate, acting as a functional element, in an acrylate hydrogel network to obtain multifunctional materials designed to perform multiple tasks in biomedical research. The hybrid material was found to be well tolerated by human fibroblast lung cells (MRC-5) (viability higher than 94%) and able to modify its swelling properties upon application of an external electric field. Release experiments performed using lysozyme as the model drug, showed a pH and electro-responsive behavior, with higher release amounts and rated in physiological vs. acidic pH. Finally, the retainment of the antioxidant properties of caffeic acid upon conjugation and polymerization processes (Trolox equivalent antioxidant capacity values of 1.77 and 1.48, respectively) was used to quench the effect of hydrogen peroxide in a hydrogel-assisted lysozyme crystallization procedure.