The Antimicrobial, Hemostatic, and Anti-Adhesion Effects of a Peptide Hydrogel Constructed by the All-d-Enantiomer of Antimicrobial Peptide Jelleine-1

Magnesium Ion/Gallic Acid MOF-Laden Multifunctional Acellular Matrix Hydrogels for Diabetic Wound Healing

The main objective for diabetic wound treatment is the design of a functional dressing that scavenges free radicals, alleviates inflammation, and is antibacterial while promoting neovascularization. Herein, a multifunctional acellular matrix hydrogel was prepared with the antimicrobial peptide jelleine-1 and a magnesium ion/gallic acid metal framework to exhibit antioxidant, anti-inflammatory, and proangiogenesis effects in diabetic wounds. The prepared hydrogel termed Gel-J-MOF efficiently released gallic acid in the acidic microenvironment of the diabetic wound, scavenged excess free radicals in vitro, and effectively reduced the levels of inflammation by regulating M2 macrophage polarization in vivo. The antimicrobial peptide jelleine-1 in the composite hydrogel effectively inhibited S. aureus and E. coli in vitro, promoting a suitable microenvironment for wound healing. In the later stage of wound healing, the composite hydrogel stimulated angiogenesis, accelerating the re-epithelialization and collagen deposition in the wound. In conclusion, this multifunctional composite hydrogel provides a regulated microenvironment for treating diabetic wounds and, therefore, has significant potential application promise in the treatment of chronic diabetic wounds.

Vascular Endothelial Growth Factor-Mimetic Peptide and Mitochondria-Targeted Antioxidant-Loaded Hydrogel System Improves Repair of Myocardial Infarction in Mice

Myocardial infarction (MI) is a pathological state characterized by persistent ischemia of the heart. Following MI, the structural and functional remodeling of the myocardium and vasculature involves oxidative stress and mitochondrial dysfunction, which exacerbate myocardial injury. Currently, there are limited effective treatments available to alleviate MI-induced damage. Vascular endothelial growth factor-mimetic (QK) peptides and mitochondria-targeted Szeto-Schiller (SS31) peptides have been extensively investigated for their therapeutic potential in various ischemic cardiomyopathies. However, traditional topical agents used in myocardial ischemia treatment suffer from limitations such as transient retention or undesirable diffusion of the drug. Consequently, a controlled drug delivery system capable of delivering QK and SS31 has gained significant attention for repair. In this study, we constructed self-assembled nanofibrous hydrogels incorporating QK and SS31 with customizable peptide amphiphilic (PA) molecules, resulting in PA1-QK and PA2-SS31 formulations. In vitro experiments demonstrated that both QK and SS31 effectively inhibited mitochondrial damage and apoptosis in a cellular hypoxia/reoxygenation (H/R) model. In vivo studies using a mouse MI model revealed that PA1-QK and PA2-SS31 significantly promoted vascular regeneration, attenuated mitochondrial dysfunction and apoptosis, and facilitated the recovery of cardiac structure and function. These results suggest that PA1-QK and PA2-SS31-loaded self-assembled nanofiber hydrogels represent an effective drug delivery system for promoting regenerative repair of myocardium and blood vessels following MI.

Ultra-short lipopeptides containing d-amino acid exhibiting excellent stability and antibacterial activity against gram-positive bacteria

As novel antibacterial agents, antimicrobial peptides (AMPs) possess broad-spectrum antibacterial activity and low drug resistance, holding significant development potential. Nevertheless, the stability of AMPs significantly restricts their application. In light of this, we synthesized a series of ultra-short lipopeptides using d-amino acid substitution to enhance the stability of ultra-short lipopeptide C12-RRW-NH2 that was selected from our previous research while maintaining its antibacterial activity against gram-positive bacteria. Amongst, the ultra-short lipopeptide Lip7 (C12-rrw-NH2) with full d-amino acid demonstrated outstanding stability in protease, serum, and salt ion environments. It exerted excellent antibacterial activity against gram-positive bacteria, especially against methicillin-resistant Staphylococcus aureus (MRSA). Meanwhile, Lip7 presented a low propensity to develop bacterial resistance with potential for combination therapy with conventional antibiotics. Studies on its antibacterial mechanism revealed that Lip7 could rapidly depolarize the bacterial cytoplasmic membrane, disrupt the integrity of the bacterial membrane, lead to leakage of nucleic acid and protein, promote the generation of reactive oxygen species, and ultimately result in bacterial death. Additionally, Lip7 also exhibited therapeutic potential in both local and systemic MRSA-infected mice models with better safety in vivo. These findings highlighted that Lip7 is an ideal novel antibacterial alternative to offer guiding schemes for developing high-stability antimicrobial peptides to fight multidrug-resistant gram-bacteria.

Bioactive hemostatic materials: a new strategy for promoting wound healing and tissue regeneration

Wound healing remains a critical global healthcare challenge, with an annual treatment cost exceeding $50 billion worldwide. Over the past decade, significant advances in wound care have focused on developing sophisticated biomaterials that promote tissue regeneration and prevent complications. Despite these developments, there remains a crucial need for multifunctional wound healing materials that can effectively address the complex, multiphase nature of wound repair while being cost effective and easily applicable in various clinical settings. This review systematically analyzes the latest developments in wound healing materials, examining their chemical composition, structural design, and therapeutic mechanisms. We comprehensively evaluate various bioactive components, including natural polymers, synthetic matrices, and hybrid composites, along with their different forms, such as hydrogels, powders, and smart dressings. Special attention is given to emerging strategies in material design that integrate multiple therapeutic functions, including sustained drug delivery, infection prevention, and tissue regeneration promotion. The insights provided in this review illuminate the path toward next-generation wound healing materials, highlighting opportunities for developing more effective therapeutic solutions that can significantly improve patient outcomes and reduce healthcare burden.

Ultrashort Peptide Hydrogels Biomaterials with Potent Antibacterial Activity

For the past few decades, ultrashort peptide hydrogels have been at the forefront of biomaterials due to their unique properties like biocompatibility, tunable mechanical properties, and potent antibacterial activity. These ultrashort peptides self-assemble into a hydrogel matrix with nanofibrous networks. In this minireview, we have explored the design and self-assembly of these ultrashort peptide hydrogels by focusing on their antibacterial properties. Cationic and hydrophobic residues are incorporated to engineer the peptides, facilitating interaction with bacterial membranes and leading to membrane disruption and cell death. The hydrogels exhibit broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. Overall, this minireview highlights the potential of ultrashort peptide hydrogels as versatile and practical antibacterial biomaterials, providing a novel approach to combating bacterial infections and addressing the growing challenge of antibiotic resistance.

Curcumin-release antibacterial dressings with antioxidation and anti-inflammatory function for diabetic wound healing and glucose monitoring

Diabetic wound healing remains a challenge due to high levels of oxidative stress, excessive inflammation, and bacterial infection. Smart dressings loaded with natural active monomers are proving to be effective strategies for enhancing diabetic wound healing. Herein, the bio-composites (PTIGA-Cur and PTIGA-Cur-Ag) with curcumin (Cur) responsive release were reported for promoting angiogenesis and diabetic wound repair, showing excellent anti-inflammatory, antioxidant, and antibacterial properties. The integration of three-dimensional networks and chemical bonds endowed the bio-composites with superior thermodynamic, mechanical, and self-healing properties. Notably, pH-responsive Schiff base as well as ester groups in the matrix enable the Cur to be released in a controlled manner. A biosensor assembled from PTIGA-Cur-Ag demonstrated electronic conductivity based on in-situ synthesis of AgNPs, which enabled sensitive monitoring of blood glucose levels. In addition, the release of AgNPs enhanced the antibacterial and anti-inflammatory properties. Expectedly, the bio-composites exhibited remarkable biocompatibility, effectively promoting the polarization of macrophages to M2 phenotype, and reducing the expression of proinflammatory cytokines. The full-thickness diabetic wound model revealed that PTIGA-Cur and PTIGA-Cur-Ag were able to effectively promote collagen deposition, neovascularization, and granulation tissue regeneration through their anti-inflammatory, antioxidant, and antibacterial properties. This study provides evidence supporting the potential utility of bio-composites with both pro-healing properties and monitoring functions in the management of diabetic wounds.

The novel β-hairpin antimicrobial peptide D-G(RF)3 demonstrates exceptional antibacterial efficacy

The clinical application of most natural antimicrobial peptides (AMPs) is hindered by their lack of a synergistic combination of high antibacterial efficacy, low toxicity, and stability, necessitating frequent complex modifications that incur significant labor and economic costs. Therefore, it is imperative to optimize the antibacterial properties of AMPs using some simplified approach. In this study, we designed a library of β-hairpin AMPs with identical β-turn sequences (-D-Pro-Gly-) and varying repetition units (IR, FR, and WK). Ultimately, candidate peptide G(RF)3 exhibited high antibacterial activity and low toxicity; however, its stability was compromised. Moreover, we synthesized the new analogue D-G(RF)3 by D-type amino acid substitution of G(RF)3, and D-G(RF)3 demonstrated concurrent high antibacterial activity, low toxicity, and remarkable stability. Interestingly, both G(RF)3 and D-G(RF)3 exerted bactericidal effects by disrupting the bacterial membrane. However, D-G(RF)3 displayed superior antibiofilm activity with a faster bactericidal rate compared to G(RF)3 and also showed enhanced synergy with antibiotics. Furthermore, D-G(RF)3 exhibited potent in vivo bactericidal activity without inducing drug resistance and has the potential to be a novel antibiotic alternative or adjuvant.

A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

JOURNAL/nrgr/04.03/01300535-202502000-00028/figure1/v/2024-05-28T214302Z/r/image-tiff Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI (QK) are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases. However, conventional topical drug delivery often results in a burst release of the drug, leading to transient retention (inefficacy) and undesirable diffusion (toxicity) in vivo. Therefore, a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke. Matrix metalloproteinase-2 (MMP-2) is gradually upregulated after cerebral ischemia. Herein, vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG (TIMP) and customizable peptide amphiphilic (PA) molecules to construct nanofiber hydrogel PA-TIMP-QK. PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro. The results indicated that PA-TIMP-QK promoted neuronal survival, restored local blood circulation, reduced blood-brain barrier permeability, and restored motor function. These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

Epidermal Sensors Constructed by a Stabilized Nanosilver Hydrogel with Self-Healing, Antimicrobial, and Temperature-Responsive Properties

The development of conductive hydrogels has garnered significant attention in the field of wearable devices and smart sensors. However, the fabrication of hydrogels that possess both multifunctionality and structural stability remains a challenging task. In this study, a novel hydrogel, PAgHCB, was synthesized using a mild method and exhibited outstanding characteristics such as electrical conductivity, self-healing capability, antimicrobial activity, dimensional stability, and temperature sensitivity. The exceptional mechanical performance (∼120 kPa at a strain of 450%) of PAgHCB is attributed to the incorporation of hydroxypropylmethylcellulose (HPMC) and the mechanical reinforcement of the gel network by carboxylated carbon nanotubes (CNT-COOH). The borate bonds between or within poly(vinyl alcohol) (PVA) chains confer self-healing capabilities upon PAgHCB, with a healing efficiency of 74.1%. The in situ reduction of silver nanoparticles through ultraviolet irradiation imparts antimicrobial characteristics to the hydrogel [against Escherichia coli, zone of inhibition (ZOI) = 3.7 mm; against Staphylococcus aureus, ZOI = 6.3 mm]. The linear temperature responsiveness of the PAgHCB hydrogel (R = -3.99T + 608.84 and COD = 0.9988) arises from the migration of silver ions within the gel matrix and the dissociation of borate bonds. Furthermore, PAgHCB was seamlessly integrated into sensors designed for monitoring human motion. The gel-based sensors exhibited three distinct sensing strain ranges corresponding to three different gauge factors (GF1 = 2.976, GF2 = 1.063, and GF3 = 2.97). Notably, PAgHCB gel sensors demonstrated the capability to detect electrical signals generated by finger and wrist joint movements and even discerned signals arising from subtle deformations induced by activities such as speaking. Additionally, the PAgHCB gel was utilized as a pressure sensor to detect external pressures applied to the skin (from 0.373 to 15.776 kPa). This work expands the avenues for designing and synthesizing multifunctional conductive hydrogels, promoting the application of hydrogel sensors with comfortable wear and high sensitivity.

Biodegradable Janus sonozyme with continuous reactive oxygen species regulation for treating infected critical-sized bone defects

Critical-sized bone defects are usually accompanied by bacterial infection leading to inflammation and bone nonunion. However, existing biodegradable materials lack long-term therapeutical effect because of their gradual degradation. Here, a degradable material with continuous ROS modulation is proposed, defined as a sonozyme due to its functions as a sonosensitizer and a nanoenzyme. Before degradation, the sonozyme can exert an effective sonodynamic antimicrobial effect through the dual active sites of MnN4 and Cu2O8. Furthermore, it can promote anti-inflammation by superoxide dismutase- and catalase-like activities. Following degradation, quercetin-metal chelation exhibits a sustaining antioxidant effect through ligand-metal charge transfer, while the released ions and quercetin also have great self-antimicrobial, osteogenic, and angiogenic effects. A rat model of infected cranial defects demonstrates the sonozyme can rapidly eliminate bacteria and promote bone regeneration. This work presents a promising approach to engineer biodegradable materials with long-time effects for infectious bone defects.

Antimicrobial Peptide Delivery Systems as Promising Tools Against Resistant Bacterial Infections

The extensive use of antibiotics during recent years has led to antimicrobial resistance development, a significant threat to global public health. It is estimated that around 1.27 million people died worldwide in 2019 due to infectious diseases caused by antibiotic-resistant microorganisms, according to the WHO. It is estimated that 700,000 people die each year worldwide, which is expected to rise to 10 million by 2050. Therefore, new and efficient antimicrobials against resistant pathogenic bacteria are urgently needed. Antimicrobial peptides (AMPs) present a broad spectrum of antibacterial effects and are considered potential tools for developing novel therapies to combat resistant infections. However, their clinical application is currently limited due to instability, low selectivity, toxicity, and limited bioavailability, resulting in a narrow therapeutic window. Here we describe an overview of the clinical application of AMPs against resistant bacterial infections through nanoformulation. It evaluates metal, polymeric, and lipid AMP delivery systems as promising for the treatment of resistant bacterial infections, offering a potential solution to the aforementioned limitations.

D-Peptide cell culture scaffolds with enhanced antibacterial and controllable release properties

The development of peptide-based hydrogels characterized by both high biostability and potent antimicrobial activity, aimed at combating multidrug-resistant bacterial infections and providing scaffolds for cell cultures, continues to pose a significant challenge. The susceptibility of antimicrobial peptides (AMPs) to degradation by cations, serum, and proteases restricted their applications in clinical environments. In this study, we designed a peptide sequence (termed D-IK1) entirely consisting of D-amino acids, an enantiomer of a previously reported AMP IK1. Our results demonstrated remarkably improved antibacterial and anticancer activities of D-IK1 as compared to IK1. D-IK1 self-assembled into hydrogels that effectively inhibited bacterial and cancer cell growth by the controlled and sustained release of D-IK1. Importantly, D-IK1 was extremely stable in salt solutions and resisted serum and protease degradation. In addition, the D-IK1 hydrogel fostered cell adhesion and proliferation, proving its viability as a 3D scaffold for cell culture applications. Our research presents a versatile, highly stable antibacterial hydrogel scaffold with potential widespread applications in cell culture, wound healing, and the eradication of multidrug-resistant bacterial infections.

A bioinspired injectable antioxidant hydrogel for prevention of postoperative adhesion

Postoperative adhesions, a prevalent complication following abdominal surgery, affect 90% of patients undergoing abdominal surgical procedures. Currently, the primary approach to prevent postoperative adhesions involves physical isolation of the surgical site and surrounding tissues using a hydrogel; however, this method represents a rudimentary strategy. Herein, considering the impact of oxidative stress and free radicals on postoperative adhesion during wound healing, an injectable antioxidant hydrogel, named PU-OHA-D, was successfully synthesized, which is formed by the crosslinking of dopamine-modified oxidized hyaluronic acid (OHA-D) and dihydrazide-terminated polyurethane (PU-ADH) through hydrazone bonding. PU-OHA-D hydrogel possesses versatile characteristics such as rapid gel formation, injectability, self-repair capability and biodegradability. Additionally, they exhibit an excellent ability to clear free radicals and superior tissue adhesion. PU-OHA-D can be injected in situ to form a hydrogel to prevent abdominal wall-cecum adhesion. Importantly, it can effectively eliminate free radicals and inhibit oxidative stress at the wound site. Thereby, it leads to collagen physiological degradation and prevents the occurrence of postoperative adhesions. The bioinspired hydrogel demonstrates its great potential in preventing postoperative adhesion and promoting wound healing.

Nanofiber Peptides for Bacterial Trapping: A Novel Approach to Antibiotic Alternatives in Wound Infections

The pervasive employment of antibiotics has engendered the advent of drug-resistant bacteria, imperiling the well-being and health of both humans and animals. Infections precipitated by such multi-resistant bacteria, especially those induced by methicillin-resistant Staphylococcus aureus (MRSA), pervade hospital settings, constituting a grave menace to patient vitality. Antimicrobial peptides (AMPs) have garnered considerable attention as a potent countermeasure against multidrug resistant bacteria. In preceding research endeavors, an insect-derived antimicrobial peptide is identified that, while possessing antimicrobial attributes, manifested suboptimal efficacy against drug-resistant Gram-positive bacteria. To ameliorate this issue, this work enhances the antimicrobial capabilities of the initial β-hairpin AMPs by substituting the structural sequence of the original AMPs with variant lengths of hydrophobic amino acid-hydrophilic amino acid repeat units. Throughout this endeavor, this work has identified a number of peptides that possess highly effective antibacterial characteristics against a wide range of bacteria. Additionally, some of these peptides have the ability to self-assemble into nanofibers, which then build networks in a distinctive manner to capture bacteria. Consequently, they represent prospective antibiotic alternatives for addressing wound infections engendered by drug-resistant bacteria.

Rational Design and Testing of Antibacterial Aloe Vera Hemostatic Hydrogel

Bleeding resulting from surgical procedures or trauma, including gunshot wounds, represents a life-threatening health issue. Therefore, the development of safe, effective, and convenient hemostatic agents is critical in securing the "golden time" to save patients' lives. Plant-derived compounds and plant extracts have been regarded as promising sources of hemostatic agents in previous studies, regulating hemostatic function with low toxicity and minimal side effects within the human body. Aloe vera-based hydrogels, which are characterized by flexible strength and high functionality, have emerged as a promising platform for wound applications due to their unique biocompatibility features. This study provides a comprehensive exploration of the utilization of thickening agents and natural agents such as xanthan gum, carrageenan, Carbomer, and alginate in applying aloe vera-based hydrogels as a hemostatic. Furthermore, it also tests the use of aloe vera-based hydrogels for therapeutic delivery at wound sites through the incorporation of various antimicrobial agents to extend the utility of the hydrogels beyond hemostasis. Our novel applied research utilizes aloe vera-based hydrogel as an antimicrobial hemostatic agent, providing valuable insights for a wide range of applications and highlighting its potential to enhance hemorrhage control in various emergency scenarios.

Electrospray Nano-Micro Composite Sodium Alginate Microspheres with Shape-Adaptive, Antibacterial, and Angiogenic Abilities for Infected Wound Healing

Nonhealing infectious wounds, characterized by bacterial colonization, wound microenvironment destruction, and shape complexity, present an intractable problem in clinical practice. Inspired by LEGOs, building-block toys that can be assembled into desired shapes, we proposed the use of electrospray nano-micro composite sodium alginate (SA) microspheres with antibacterial and angiogenic properties to fill irregularly shaped wounds instantly. Specifically, porous poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) encapsulating basic fibroblast growth factor (bFGF) were produced by a water-in-oil-in-water double-emulsion method. Then, bFGF@MSs were blended with the SA solution containing ZIF-8 nanoparticles. The resultant solution was electrosprayed to obtain nano-micro composite microspheres (bFGF@MS/ZIF-8@SAMSs). The composite MSs' size could be regulated by PLGA MS mass proportion and electrospray voltage. Moreover, bFGF, a potent angiogenic agent, and ZIF-8, bactericidal nanoparticles, were found to release from bFGF@MS/ZIF-8@SAMSs in a controlled and sustainable manner, which promoted cell proliferation, migration, and tube formation and killed bacteria. Through experimentation on rat models, bFGF@MS/ZIF-8@SAMSs were revealed to adapt to wound shapes and accelerate infected wound healing because of the synergistic effects of antibacterial and angiogenic abilities. In summation, this study developed a feasible approach to prepare bioactive nano-micro MSs as building blocks that can fill irregularly shaped infected wounds and improve healing.

Injectable self-assembled GDF5-containing dipeptide hydrogels for enhanced tendon repair

Owing to the tissue characteristics of tendons with few blood vessels and cells, the regeneration and repair of injured tendons can present a considerable challenge, which considerably affects the motor function of limbs and leads to serious physical and mental pain, along with an economic burden on patients. Herein, we designed and fabricated a dipeptide hydrogel (DPH) using polypeptides P11-4 and P11-8. This hydrogel exhibited self-assembly characteristics and could be administered in vitro. To endow the hydrogel with differentiation and regeneration abilities, we added different concentrations of growth differentiation factor 5 (GDF5) to form GDF5@DPH. GDF5@DPH promoted the aggregation and differentiation of tendon stem/progenitor cells and promoted the regeneration and repair of tendon cells and collagen fibers in injured areas. In addition, GDF5@DPH inhibited inflammatory reactions in the injured area. Owing to its injectable properties, DPH can jointly inhibit adhesion and scar hyperplasia between tissues caused by endogenous inflammation and exogenous surgery and can provide a favorable internal environment for the regeneration and repair of the injured area. Overall, the GDF5@DPH system exhibits considerable promise as a novel approach to treating tendon injury.

Screening and investigation of a short antimicrobial peptide: AVGAV

Bacterial resistance to various drugs is a major problem concerning the field of antibacterial agents. Fortunately, peptides with antibacterial activity can alleviate this problem. In this study, a short peptide (AVGAV) with excellent antibacterial activity was successfully screened from a peptide library by a self-made membrane chromatographic packing. The AVGAV peptide exhibits good biocompatibility and is non-toxic and non-irritating, which ensures that it presents safe antibacterial effects. AVGAV promoted wound healing in a mouse wound bacterial infection model. Most importantly, as a synthetic antimicrobial peptide, AVGAV can alleviate the problem of bacterial resistance, thus improving its application potential. This study provides a solution to the existing and potential problem of bacterial resistance.