Fast in situ generated ɛ-polylysine-poly (ethylene glycol) hydrogels as tissue adhesives and hemostatic materials using an enzyme-catalyzed method

Swift Covalent Gelation Coupled with Robust Wet Adhesive Powder: A Novel Approach for Acute Massive Hemorrhage Control in Dynamic and High-Pressure Wound Environments

The quest for efficient hemostatic agents in emergency medicine is critical, particularly for managing massive hemorrhages in dynamic and high-pressure wound environments. Traditional self-gelling powders, while beneficial due to their ease of application and rapid action, fall short in such challenging conditions. To bridge this gap, the research introduces a novel self-gelling powder that combines ultrafast covalent gelation and robust wet adhesion, presenting a significant advancement in acute hemorrhage control. This ternary system comprises ε-polylysine (ε-PLL) and 4-arm polyethylene glycol succinyl succinate (4-arm-PEG-NHS) forming the hydrogel framework. Na2HPO4 functions as the "H+ sucker" to expedite the amidation reaction, slashing gelation time to under 10 s, crucial for immediate blood loss restriction. Moreover, PEG chains' hydrophilicity facilitates efficient absorption of interfacial blood, increasing the generated hydrogel's cross-linking density and strengthens its tissue bonding, thereby resulting in excellent mechanical and wet adhesion properties. In vitro experiments reveal the optimized formulation's exceptional tissue compliance, procoagulant activity, biocompatibility and antibacterial efficacy. In porcine models of heart injuries and arterial punctures, it outperforms commercial hemostatic agent Celox, confirming its rapid and effective hemostasis. Conclusively, this study presents a transformative approach to hemostasis, offering a reliable and potent solution for the emergency management of massive hemorrhage.

Antibacterial polylysine-containing hydrogels for hemostatic and wound healing applications: preparation methods, current advances and future perspectives

The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.

Engineered Hemostatic Biomaterials for Sealing Wounds

Hemostatic biomaterials show great promise in wound control for the treatment of uncontrolled bleeding associated with damaged tissues, traumatic wounds, and surgical incisions. A surge of interest has been directed at boosting hemostatic properties of bioactive materials via mechanisms triggering the coagulation cascade. A wide variety of biocompatible and biodegradable materials has been applied to the design of hemostatic platforms for rapid blood coagulation. Recent trends in the design of hemostatic agents emphasize chemical conjugation of charged moieties to biomacromolecules, physical incorporation of blood-coagulating agents in biomaterials systems, and superabsorbing materials in either dry (foams) or wet (hydrogel) states. In addition, tough bioadhesives are emerging for efficient and physical sealing of incisions. In this Review, we highlight the biomacromolecular design approaches adopted to develop hemostatic bioactive materials. We discuss the mechanistic pathways of hemostasis along with the current standard experimental procedures for characterization of the hemostasis efficacy. Finally, we discuss the potential for clinical translation of hemostatic technologies, future trends, and research opportunities for the development of next-generation surgical materials with hemostatic properties for wound management.

Effect of crosslinking strategy on the biological, antibacterial and physicochemical performance of hyaluronic acid and ɛ-polylysine based hydrogels

The design of multifunctional hydrogels based on bioactive hyaluronic acid (HA) and antibacterial cationic polymer ɛ-poly-l-lysine (ε-PL) is a promising tool in tissue engineering applications. In the current study, we have designed hyaluronic acid and ɛ-polylysine composite hydrogel systems with antibacterial and cell attractive properties. Two distinct crosslinking approaches were used: the physical crosslinking based on electrostatic attractions and the chemical crosslinking of charged functional groups (-NH₂ and -COOH). The impact of the crosslinking strategy on fabricated hydrogel molecular structure, swelling behavior, gel fraction, morphology, porosity, viscoelastic properties, antibacterial activity, and in vitro biocompatibility was evaluated. Both chemically and physically crosslinked HA/ԑ-PL hydrogels demonstrated fast swelling behavior and long-term stability for at least 28 days, as well as similar order of stiffness (10-30 kPa). We demonstrated that physically crosslinked hydrogels inhibited over 99.999% of Gram-negative E. coli, while chemically crosslinking strategy led to the antibacterial efficiency decrease. However, cell viability was significantly improved, confirming the importance of the applied crosslinking approach to the antibacterial activity and in vitro biocompatibility. The distinct differences in the physicochemical and biological properties of the developed materials provide new opportunities to design next-generation functional composite hydrogel systems.

By Endowing Polyglutamic Acid/Polylysine Composite Hydrogel with Super Intrinsic Characteristics to Enhance its Wound Repair Potential

In this study, multifunctional porous composite hydrogels are prepared via composite technology and using poly(glutamic acid) and (polylysine) as precursors, casein as foaming agent, and calcium ions as coagulant. The results show that the as-prepared hydrogels have high porosity and water absorbency, and good mechanical, inherent antibacterial, and bioadhesive properties. The results show such high water absorption, bioadhesion, and porosity of the as-prepared hydrogel can effectively concentrate blood components and seal wounds better. The release of calcium ions in the as-prepared hydrogels can activate coagulation factors. Both factors can play an important role in hemostasis. The excellent hydroscopicity, moisture retention, adhesion, and inherent antibacterial properties of the as-prepared hydrogel can create a moist, sterile, and closed microenvironment for the wound healing. The experimental results of a deep skin defect model have verified its good effect of promoting wound repair. These inherent excellent properties can endow the as-prepared hydrogel with a wide range of application values.

Uniting Electroceutical and Cosmeceutical Interventions in Combating Coronavirus Using Ԑ-Poly-l-Lysine

Combating the COVID-19 pandemic warrants the exploitation of all the available tools and implies a major focus on both the biological and the physical properties of the causing virus (SARS-CoV2). We hereby introduce a new prophylaxis hypothesis by decreasing the viral load in the body entrances such as the nose and the mouth using pharmaceutical and cosmeceutical preparations that incorporate viral electrostatic repulsive nanofibers fabricated from an abundant marine-derived or a fermentation product polymer; Ԑ-poly-l-lysine was prepared using the electrospinning technique.

Polymeric Hydrogel Systems as Emerging Biomaterial Platforms to Enable Hemostasis and Wound Healing

Broad interest in developing new hemostatic technologies arises from unmet needs in mitigating uncontrolled hemorrhage in emergency, surgical, and battlefield settings. Although a variety of hemostats, sealants, and adhesives are available, development of ideal hemostatic compositions that offer a range of remarkable properties including capability to effectively and immediately manage bleeding, excellent mechanical properties, biocompatibility, biodegradability, antibacterial effect, and strong tissue adhesion properties, under wet and dynamic conditions, still remains a challenge. Benefiting from tunable mechanical properties, high porosity, biocompatibility, injectability and ease of handling, polymeric hydrogels with outstanding hemostatic properties have been receiving increasing attention over the past several years. In this review, after shedding light on hemostasis and wound healing processes, the most recent progresses in hydrogel systems engineered from natural and synthetic polymers for hemostatic applications are discussed based on a comprehensive literature review. Most studies described used in vivo models with accessible and compressible wounds to assess the hemostatic performance of hydrogels. The challenges that need to be tackled to accelerate the translation of these novel hemostatic hydrogel systems to clinical practice are emphasized and future directions for research in the field are presented.

Structure and sequence features of mussel adhesive protein lead to its salt-tolerant adhesion ability

Mussels can strongly adhere to hydrophilic minerals in sea habitats by secreting adhesive proteins. The adhesion ability of these proteins is often attributed to the presence of Dopa derived from posttranslational modification of Tyr, whereas the contribution of structural feature is overlooked. It remains largely unknown how adhesive proteins overcome the surface-bound water layer to establish underwater adhesion. Here, we use molecular dynamics simulations to probe the conformations of adhesive protein Pvfp-5β and its salt-tolerant underwater adhesion on superhydrophilic mica. Dopa and positively charged basic residues form pairs, in this intrinsically disordered protein, and these residue pairs can lead to firm surface binding. Our simulations further suggest that the unmodified Tyr shows similar functions on surface adhesion by forming pairing structure with a positively charged residue. We confirm the presence of these residue pairs and verify the strong binding ability of unmodified proteins using nuclear magnetic resonance spectroscopy and lap shear tests.

Gel-like ionic complexes for antimicrobial, hemostatic and adhesive properties

Ion-specific effects offer a great opportunity to construct intelligent macromolecular systems with diverse architectures, on-demand controlled release behaviors and interfacial responsiveness.

Enzyme-induced dual-network ε-poly-l-lysine-based hydrogels with robust self-healing and antibacterial performance

An enzyme-induced strategy is reported to construct novel self-mending hydrogels based on ε-poly-l-lysine with both excellent self-healing properties (95%) and antibacterial capacity. Most importantly, the hydrogels are able to accelerate wound healing efficiently, which shows great potential in myriad biomedical fields, such as wound repair, artificial skin, and tissue engineering.

Horseradish peroxidase-catalyzed hydrogelation for biomedical applications

Hydrogels catalyzed by horseradish peroxidase (HRP) serve as an efficient and effective platform for biomedical applications due to their mild reaction conditions for cells, fast and adjustable gelation rate in physiological conditions, and an abundance of substrates as water-soluble biocompatible polymers.

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.

Photo-cross-linked biodegradable hydrogels based on n-arm-poly(ethylene glycol), poly(ε-caprolactone) and/or methacrylic acid for controlled drug release

In this paper, a novel kind of photo-cross-linked biodegradable hydrogels based on n-arm-poly(ethylene glycol) ( n = 2, 3, and 4) and poly(ɛ-caprolactone) was prepared by ultraviolet-initiated free radical polymerization. The resulting n-arm-poly(ethylene glycol)-poly(ɛ-caprolactone) and n-arm-poly(ethylene glycol)-poly(ɛ-caprolactone) acrylate (n-arm-PEG-PCL-AC, macromer) were characterized by proton nuclear magnetic resonance and fourier transform infrared spectra. The influences of arm numbers and concentration of macromer on the properties of hydrogel were researched systematically, and the results showed that the gelation time, equilibrium swelling ratio, in vitro degradation, and drug release rate decreased with the increase of arm numbers and concentration of macromer. The degradation and drug release rate could be controlled by varying the cross-linking density of hydrogel, indicating a potential application as controlled drug delivery system. Cytotoxicity test of hydrogel extracts was conducted using L929 mouse fibroblasts, and the relative growth rate exceeded 75% (cytotoxicity type: class 1) after incubation for 24 h, showing excellent cytocompatibility. In addition, the paper presented a pH-sensitive hydrogel (G4_pH) based on 4-arm-PEG-PCL-AC and acrylic acid, and the influences of pH value on swelling behaviors and in vitro drug release of the pH-sensitive hydrogel were examined. The hydrogels shrank under acidic condition and would swell in neutral or basic medium. The pH-dependent drug release behaviors indicated a promising application of the materials as oral drug delivery vehicles.

In situ forming gelatin hydrogels by dual-enzymatic cross-linking for enhanced tissue adhesiveness

In situ forming hydrogels show promise as therapeutic implants and carriers in a wide range of biomedical applications.

Tannin-based adhesive for protection of colonic anastomosis in the open abdomen

This study was aimed to evaluate the effect of tannin acid- polyethylene glycol (TP) adhesive on the wound healing process of primary colonic anastomosis in the open abdomen (OA). Adhesion strength test, degradation and hemostatic ability of TP were investigated. In a rat model, after standard colonic anastomoses, rats were divided into three groups: OA group; OA + FG (fibrin glue) group; OA + TP group. Five days after surgery, body weight, anastomotic bursting pressure (ABP), and histology of anastomotic tissue were evaluated. Performance of adhesion strength and hemostatic ability of TP was better than that of FG. The weight of TP decreased by over 50% after 11-day incubation. All rats survived well after surgery. Compared to OA group and OA + FG group, OA + TP group showed a significant improvement in body weight, ABP and healing state. Application of TP adhesive, used as an auxiliary treatment of colonic anastomosis operation, improved the wound strength and promoted the anastomotic healing after OA.

Antimicrobial and biocompatible ε-polylysine–γ-poly(glutamic acid)–based hydrogel system for wound healing

Biocompatible and antimicrobial wound dressings are important biomaterials for tissue adhesion and healing. Hydrogels derived from natural polyamino acids are ideal wound dressing because of their good water solubility, biocompatibility, and biodegradability. In this study, we introduce poly(amino acid)–based hydrogels as a new type of wound dressing for wound healing. The composite hydrogels were derived from water-soluble ε-polylysine and γ-poly(glutamic acid) cross-linked by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxy-succinimide. The gelation is attributed to the reaction between the amino groups of ε-polylysine and carboxyl groups of γ-poly(glutamic acid). Fourier transform infrared spectroscopy was used to characterize the composite hydrogels. The effect of the ratio of ε-polylysine and γ-poly(glutamic acid) on the gelation time, surface morphology, equilibrium swelling, elastic moduli, adhesive strength, and in vitro degradation of composite hydrogels was examined. The hydrogels showed excellent antimicrobial efficacy against Escherichia coli and Staphylococcus aureus. Indirect cytotoxicity assessment indicated that the composite hydrogels were nontoxic to the L929 cell. The potential of the composite hydrogel as wound dressing was demonstrated by applying it in the skin incision. Results demonstrated that the composite hydrogel showed superior healing effects compared with suture, fibrin glue, and compont skin adhesive, while eliciting less inflammatory response. In conclusion, antimicrobial and biocompatible ε-polylysine–γ-poly(glutamic acid) composite may have great application for wound healing.

Enzymatically crosslinked epsilon-poly-l-lysine hydrogels with inherent antibacterial properties for wound infection prevention

Anin situforming hydrogel derived from epsilon-poly-l-lysine was crosslinked by the enzymatic catalysis method and showed excellent antibacterial properties for wound infection prevention.

The gelation process and protein absorption property of injectable SA-CMBC hydrogel used for procoagulant material

CMBC showed obvious influence on properties of injectable SA-CMBC hydrogel, containing gelation time, mechanical property, protein absorption and procoagulant property.