Bioadhesives with Antimicrobial Properties

Strong Bioadhesives from Helical Polypeptides

Bioadhesives have emerged as versatile and powerful tools for tissue repair and integration with biomedical devices, offering a wide range of applications that have captured significant clinical and scientific interest. Synthetic polypeptide adhesives are particularly promising candidates for bioadhesives, but often face limitations in adhesive strength. In this study, inspired by marine adhesive proteins, the secondary structure and hydrophobic-hydrophilic balance of polypeptides were precisely regulated to transform the polyelectrolyte to a strong adhesive. The resulting polypeptide adhesive demonstrated an adhesive strength exceeding 1.0 MPa, more than 10× higher than that of the previously reported synthetic polypeptide adhesive. The cohesion and adhesion of polypeptide adhesive can be optimized by adjusting the content of the secondary structure and hydrophobic residue ratios. More helices in polypeptides enhance the interactions between the polypeptide backbone and side chains as well as the interactions between polypeptides and substrates. In addition, these polypeptide adhesives exhibit excellent tolerance to strong acids or alkalis, remarkable adhesion to variable materials and tissues, and an impressive sealing performance.

Durable and biocompatible low adhesion wound dressing material based on interfacial behaviors for wound management

Wound-dressing adhesion is a problem that has not been effectively addressed in the field of wound care for bleeding or burn wounds. Design of low adhesion wound dressing materials by leveraging interfacial behaviors has been an effective solution to this problem. However, previously reported superhydrophobic low adhesion materials either had durability or biocompatibility issue. To bridge this gap, this study presents a durable and biocompatible superhydrophobic low adhesion wound dressing material, which is designed on a normal gauze substrate with biocompatible components using a hybrid coating strategy. Outstanding low adhesion properties have been verified in vivo with bleeding wound or burn wound, with a peeling force that is only 0.3 %-14.5 % of the conventional non-woven gauze. Prepared low adhesion materials can robustly retain their superhydrophobicity and blood-repelling properties against harsh tests. Moreover, their biocompatibility has been confirmed through a series of tests including cell biocompatibility, hemolysis and skin irritation tests. With these demonstrated merits, the durable and biocompatible low adhesion material developed in this study will provide an effective solution to the wound adhesion problem in the practice of wound management.

Supramolecular interactions-driven aggregation to prepare lipoic acid-bioadhesives for seawater-immersed wounds

Seawater-immersed wounds can be threatened by high pH, high permeability and infection, which may lead to the development of chronic wounds. The present study develops an aggregation strategy for the rapid preparation of α-lipoic acid (LA)-based bioadhesives at room temperature with strong and underwater adhesion for emergency treatment of trauma in maritime activities. The bioadhesives are fabricated from the aggregation of LA, MXene and Ag+ through their supramolecular interactions, which can be rapidly formed in mild environments, showing strong interface adhesion without adhesive failure caused by depolymerization, while exhibiting mechanical self-reinforcing. To further improve the adhesive strength, the formation of MXene/Ag+/LA interactions was integrated into poly(2-hydroxyethyl methacrylate) (pHEMA) electrospinning to manufacture electrospun film with the adhesion strength as high as 2 MPa. The bioadhesives are sensitive to alkaline environments and can lead to deprotonation of LA. The released H+ can instantly adjust the pH of weakly alkaline seawater-immersed wounds to normal pH, while deprotonated LA is released into wounds to exert anti-inflammatory functions. Together with antibacterial property, bioadhesives applied to seawater-immersed wounds provide stable barrier protection and correct adverse microenvironment, promoting wound healing.

Bifunctional Electrospun Nanocomposite Dressing: Integrating Antibacterial Efficacy and Controllable Antioxidant Properties for Expedited Wound Healing

Current wound dressings are insufficient in simultaneously addressing bacterial infections and oxidative stress, which severely affects wound healing outcomes. To solve this problem, we introduced poly(ionic liquid) (PIL) with strong antibacterial properties and cerium oxide nanoparticles (CeO2NPs) with excellent antioxidant capabilities into polyacrylonitrile (PAN) nanofiber membranes to prepare a novel composite dressing. The PIL-CeO2NPs-PAN nanofiber membrane provides sustained antibacterial activity through stably embedded PIL, while the uniformly distributed CeO2NPs achieve controlled release, avoiding safety issues caused by the rapid release of active substances. In vitro and in vivo experiments demonstrated that the membrane exhibits outstanding biocompatibility, significant antibacterial effects (inhibition rates of 88.3% against Escherichia coli and 93.2% against Staphylococcus aureus), and excellent antioxidant performance (64.7% reactive oxygen species scavenging rate). More importantly, PIL-CeO2NPs-PAN achieved a 94.1% wound healing rate within 14 days, significantly superior to traditional treatment methods. The results indicate that this composite membrane significantly improves wound healing by simultaneously resisting infection and oxidative stress, providing a safe and effective new option for clinical applications. Our work offers an innovative design strategy that combines antibacterial and antioxidant mechanisms for wound care.

Ferric Iron/Shikonin Nanoparticle-Embedded Hydrogels with Robust Adhesion and Healing Functions for Treating Oral Ulcers in Diabetes

Oral ulcers can be addressed using various biomaterials designed to deliver medications or cytokines. Nevertheless, the effectiveness of these substances is frequently limited in many patients due to poor adherence, short retention time in the mouth, and less-than-optimal drug efficacy. In this study, a new hydrogel patch (FSH3) made of a silk fibroin/hyaluronic acid matrix with light-sensitive adhesive qualities infused with ferric iron/shikonin nanoparticles to enhance healing effects is presented. Initially, this hydrogel forms an adhesive barrier over mucosal lesions through a straightforward local injection, solidifying when exposed to UV light. Subsequently, FSH3 demonstrates superior reactive oxygen species elimination and near-infrared photothermal bactericidal activity. These characteristics support bacterial elimination and regulate oxidative levels, promoting a wound's progression from inflammation to tissue regeneration. In a diabetic rat model mimicking oral ulcers, FSH3 significantly speeds up healing by adjusting the inflammatory environment of the injured tissue, maintaining balance in oral microbiota, and promoting faster re-epithelialization. Overall, the light-sensitive FSH3 hydrogel shows potential for rapid wound recovery and may transform therapeutic methods for managing oral ulcers in diabetes.

A New Strategy to Inhibit Scar Formation by Accelerating Normal Healing Using Silicate Bioactive Materials

Inspired by the scar-free wound healing in infants, an anti-scar strategy is proposed by accelerating wound healing using silicate bioactive materials. Bioglass/alginate composite hydrogels are applied, which significantly inhibit scar formation in rabbit ear scar models. The underlining mechanisms include stimulation of Integrin Subunit Alpha 2 expression in dermal fibroblasts to accelerate wound healing, and induction of apoptosis of hypertrophic scar fibroblasts by directly stimulating the N-Acylsphingosine Amidohydrolase 2 expression in hypertrophic scar fibroblasts, and indirectly upregulating the secretion of Cathepsin K in dermal fibroblasts. Considering specific functions of the bioactive silicate materials, two scar treatment regimes are tested. For severe scars, a regenerative intervention is applied by surgical removal of the scar followed by the treatment with bioactive hydrogels to reduce the formation of scars by activating dermal fibroblasts. For mild scars, the bioactive dressing is applied on the formed scar and reduces scar by inducing scar fibroblasts apoptosis.

Artificial Bacteriophages for Treating Oral Infectious Disease via Localized Bacterial Capture and Enhanced Catalytic Sterilization

With the rapid emergence of antibiotic-resistant pathogens, nanomaterial-assisted catalytic sterilization has been well developed to combat pathogenic bacteria by elevating the level of reactive oxygen species including hydroxyl radical (·OH). Although promising, the ultra-short lifetime and limited diffusion distance of ·OH severely limit their practical antibacterial usage. Herein, the rational design and preparation of novel virus-like copper silicate hollow spheres (CSHSs) are reported, as well as their applications as robust artificial bacteriophages for localized bacterial capture and enhanced catalytic sterilization in the treatment of oral infectious diseases. During the whole process of capture and killing, CSHSs can efficiently capture bacteria via shortening the distance between bacteria and CSHSs, produce massive ·OH around bacteria, and further iinducing the admirable effect of bacterial inhibition. By using mucosal infection and periodontitis as typical oral infectious diseases, it is easily found that the bacterial populations around lesions in animals after antibacterial treatment fall sharply, as well as the well-developed nanosystem can decrease the inflammatory reaction and promote the hard or soft tissue repair. Together, the high Fenton-like catalytic activity, strong bacterial affinity, excellent antibacterial activity, and overall safety of the nanoplatform promise its great therapeutic potential for further catalytic bacterial disinfection.

Rapidly Gelled Lipoic Acid-Based Supramolecular Hydrogel for 3D Printing of Adhesive Bandage

Developing a strongly adhesive, easily removable, and robust bandage is valuable in trauma emergencies. Poly(lipoic acid) (PLA)-based adhesives with good mechanical properties have been well-developed through a thermal ring-opening polymerization (ROP) method that is easiness. However, the additive manufacturing of PLA-based adhesives remains a challenge. Herein, α-lipoic acid (LA) and trometamol (Tris) are found to rapidly form a supramolecular hydrogel at room temperature with injectability and 3D printing potential. Meanwhile, the synthesized LA-grafted hyaluronic acid and cellulose nanocrystals are involved not only to optimize the extrusion of 3D printing but also to effectively promote fidelity and prevent the inverse closed-loop depolymerization of PLA in water. The hydrogel bandage exhibits strong adhesion to skin while it can be removed with no residue by water flushing, showing protection to neo-tissue during dressing replacement. The in vivo application of the hydrogel bandage significantly promoted wound healing by closing the wound, forming a physical barrier, and providing an anti-inflammatory effect, showing great potential in future clinical applications.

Influence of Physicochemical Properties of Iron Oxide Nanoparticles on Their Antibacterial Activity

The increasing occurrence of infectious diseases caused by antimicrobial resistance organisms urged the necessity to develop more potent, selective, and safe antimicrobial agents. The unique magnetic and tunable properties of iron oxide nanoparticles (IONPs) make them a promising candidate for different theragnostic applications, including antimicrobial agents. Though IONPs act as a nonspecific antimicrobial agent, their antimicrobial activities are directly or indirectly linked with their synthesis methods, synthesizing precursors, size, shapes, concentration, and surface modifications. Alteration of these parameters could accelerate or decelerate the production of reactive oxygen species (ROS). An increase in ROS role production disrupts bacterial cell walls, cell membranes, alters major biomolecules (e.g., lipids, proteins, nucleic acids), and affects metabolic processes (e.g., Krebs cycle, fatty acid synthesis, ATP synthesis, glycolysis, and mitophagy). In this review, we will investigate the antibacterial activity of bare and surface-modified IONPs and the influence of physiochemical parameters on their antibacterial activity. Additionally, we will report the potential mechanism of IONPs' action in driving this antimicrobial activity.

Principles and Design of Bionic Hydrogel Adhesives for Skin Wound Treatment

Over millions of years of evolution, nature has developed a myriad of unique features that have inspired the design of adhesives for wound healing. Bionic hydrogel adhesives, capable of adapting to the dynamic movements of tissues, possess superior biocompatibility and effectively promote the healing of both external and internal wounds. This paper provides a systematic review of the design and principles of these adhesives, focusing on the treatment of skin wounds, and explores the feasibility of incorporating nature-inspired properties into their design. The adhesion mechanisms of bionic adhesives are analyzed from both chemical and physical perspectives. Materials from natural and synthetic polymers commonly used as adhesives are detailed regarding their biocompatibility and degradability. The multifunctional design elements of hydrogel adhesives for skin trauma treatment, such as self-healing, drug release, responsive design, and optimization of mechanical and physical properties, are further explored. The aim is to overcome the limitations of conventional treatments and offer a safer, more effective solution for the application of bionic wound dressings.

High-Performance Engineered Composites Biofabrication Using Fungi

Various natural polymers offer sustainable alternatives to petroleum-based adhesives, enabling the creation of high-performance engineered materials. However, additional chemical modifications and complicated manufacturing procedures remain unavoidable. Here, a sustainable high-performance engineered composite that benefits from bonding strategies with multiple energy dissipation mechanisms dominated by chemical adhesion and mechanical interlocking is demonstrated via the fungal smart creative platform. Chemical adhesion is predominantly facilitated by the extracellular polymeric substrates and glycosylated proteins present in the fungal outer cell walls. The dynamic feature of non-covalent interactions represented by hydrogen bonding endows the composite with extensive unique properties including healing, recyclability, and scalable manufacturing. Mechanical interlocking involves multiple mycelial networks (elastic modulus of 2.8 GPa) binding substrates, and the fungal inner wall skeleton composed of chitin and β-glucan imparts product stability. The physicochemical properties of composite (modulus of elasticity of 1455.3 MPa, internal bond strength of 0.55 MPa, hardness of 82.8, and contact angle of 110.2°) are comparable or even superior to those of engineered lignocellulosic materials created using petroleum-based polymers or bioadhesives. High-performance composite biofabrication using fungi may inspire the creation of other sustainable engineered materials with the assistance of the extraordinary capabilities of living organisms.

Hemostatic and Ultrasound-Controlled Bactericidal Silk Fibroin Hydrogel via Integrating a Perfluorocarbon Nanoemulsion

Excessive blood loss and infections are the prominent risks accounting for mortality and disability associated with acute wounds. Consequently, wound dressings should encompass adequate adhesive, hemostatic, and bactericidal attributes, yet their development remains challenging. This investigation presented the benefits of incorporating a perfluorocarbon nanoemulsion (PPP NE) into a silk-fibroin (SF)-based hydrogel. By stimulating the β-sheet conformation of the SF chains, PPP NEs drastically shortened the gelation time while augmenting the elasticity, mechanical stability, and viscosity of the hydrogel. Furthermore, the integration of PPP NEs improved hemostatic competence by boosting the affinity between cells and biomacromolecules. It also endowed the hydrogel with ultrasound-controlled bactericidal ability through the inducement of inner cavitation by perfluorocarbon and reactive oxygen species (ROS) generated by the sonosensitizer protoporphyrin. Ultimately, we employed a laparotomy bleeding model and a Staphylococcus aureus-infected trauma wound to demonstrate the first-aid efficacy. Thus, our research suggested an emulsion-incorporating strategy for managing emergency wounds.

Natural polyphenolic antibacterial bio-adhesives for infected wound healing

Bio-adhesives used clinically, commonly have the ability to fill surgical voids and support wound healing, but which are devoid of antibacterial activity, and thus, could not meet the particular needs of the infected wound site. Herein, a series of natural polyphenolic antibacterial bio-adhesives were prepared via simple mixing and heating of polyphenols and acid anhydrides without any solvent or catalyst. Upon the acid anhydride ring opening and acylation reactions, various natural polyphenolic bio-adhesives could adhere to various substrates (i.e., tissue, wood, glass, rubber, paper, plastic, and metal) based on multi-interactions. Moreover, these bio-adhesives showed excellent antibacterial and anti-infection activity, rapid hemostatic performance and appropriate biodegradability, which could be widely used in promoting bacterial infection wound healing and hot burn infection wound repair. This work could provide a new strategy for strong adhesives using naturally occurring molecules, and provide a method for the preparation of novel multifunctional wound dressings for infected wound healing.

Chlorella-Loaded Antibacterial Microneedles for Microacupuncture Oxygen Therapy of Diabetic Bacterial Infected Wounds

Hypoxia and infection are urgent clinical problems in chronic diabetic wounds. Herein, living Chlorella-loaded poly(ionic liquid)-based microneedles (PILMN-Chl) are constructed for microacupuncture oxygen and antibacterial therapy against methicillin-resistant Staphylococcus aureus (MRSA)-infected chronic diabetic wounds. The PILMN-Chl can stably and continuously produce oxygen for more than 30 h due to the photosynthesis of the loaded self-supported Chlorella. By combining the barrier penetration capabilities of microneedles, the continuous and sufficient oxygen supply of Chlorella, and the sterilization activities of PIL, the PILMN-Chl can accelerate chronic diabetic wounds in vivo by topical targeted sterilization and hypoxia relief in deep parts of wounds. Thus, the self-oxygen produced microneedles modality may provide a promising and facile therapeutic strategy for treating chronic, hypoxic, and infected diabetic wounds.

Metal-Phenolic Networks for Chronic Wounds Therapy

Chronic wounds are recalcitrant complications of a variety of diseases, with pathologic features including bacterial infection, persistent inflammation, and proliferation of reactive oxygen species (ROS) levels in the wound microenvironment. Currently, the use of antimicrobial drugs, debridement, hyperbaric oxygen therapy, and other methods in clinical for chronic wound treatment is prone to problems such as bacterial resistance, wound expansion, and even exacerbation. In recent years, researchers have proposed many novel materials for the treatment of chronic wounds targeting the disease characteristics, among which metal-phenolic networks (MPNs) are supramolecular network structures that utilize multivalent metal ions and natural polyphenols complexed through ligand bonds. They have a flexible and versatile combination of structural forms and a variety of formations (nanoparticles, coatings, hydrogels, etc.) that can be constructed. Functionally, MPNs combine the chemocatalytic and bactericidal properties of metal ions as well as the anti-inflammatory and antioxidant properties of polyphenol compounds. Together with the excellent properties of rapid synthesis and negligible cytotoxicity, MPNs have attracted researchers' great attention in biomedical fields such as anti-tumor, anti-bacterial, and anti-inflammatory. This paper will focus on the composition of MPNs, the mechanisms of MPNs for the treatment of chronic wounds, and the application of MPNs in novel chronic wound therapies.