Biopolymer Nano-Network for Antimicrobial Peptide Protection and Local Delivery

The Promoting Effect of Animal Bioactive Proteins and Peptide Components on Wound Healing: A Review

The skin is the first line of defense to protect the host from external environmental damage. When the skin is damaged, the wound provides convenience for the invasion of external substances. The prolonged nonhealing of wounds can also lead to numerous subsequent complications, seriously affecting the quality of life of patients. To solve this problem, proteins and peptide components that promote wound healing have been discovered in animals, which can act on key pathways involved in wound healing, such as the PI3K/AKT, TGF-β, NF-κ B, and JAK/STAT pathways. So far, some formulations for topical drug delivery have been developed, including hydrogels, microneedles, and electrospinning nanofibers. In addition, some high-performance dressings have been utilized, which also have great potential in wound healing. Here, research progress on the promotion of wound healing by animal-derived proteins and peptide components is summarized, and future research directions are discussed.

Integrated computational approaches for advancing antimicrobial peptide development

The increasing prevalence of antimicrobial resistance has intensified the need for novel antimicrobial drugs. Antimicrobial peptides (AMPs) are promising alternative antibiotics due to their broad-spectrum activity and slower resistance development. However, the time-consuming, costly development and challenge of systematic optimization limit their translation into the clinic. Recently, integrating computational methods have led to breakthroughs in the precise design and optimization of AMPs, reduced resource consumption, and accelerated AMP development process. We highlight the application of these integrated approaches in AMP molecule discovery, optimization, and delivery and demonstrate the synergy of these strategies to fuel AMP development.

Silver Nanowire Reinforced Conductive and Injectable Colloidal Gel for Effective Wound Healing Via Electrical Stimulation

The remarkable biocapacity, injectability, and adaptability of colloidal gels lead to their widespread use in tissue engineering as irregular defect implants. However, multifunctionalities including electroconductivity and antibacterial property are highly required for colloidal gels. In addition, the inherently weak mechanical property of physically crosslinked colloidal gels limits their application. Herein, Ag nanowires (Ag NWs)-reinforced colloidal gels composed of biocompatible gelatin nanoparticles and polydopamine-modified Ag NWs through the controlled electrostatic assembly, which are injectable and conductive, are presented. 1D Ag NWs can significantly improve the mechanical and electrical properties of the colloidal gel while maintaining its inherent excellent injectability. Owing to the network of Ag NWs, the storage modulus and conductivity of the optimized Ag NW colloidal gel are 7.5 and 13 times higher, respectively, than those of the colloidal gel made up of polydopamine-modified Ag nanoparticles with equivalent Ag concentration. Further, this Ag NW colloidal gel can adapt to sharp wounds on skin, which accelerates the healing of an MRSA-infected wound via electrical stimulation.

Antimicrobial Peptides and Their Biomedical Applications: A Review

The emergence of drug resistance genes and the detrimental health effects caused by the overuse of antibiotics are increasingly prominent problems. There is an urgent need for effective strategies to antibiotics or antimicrobial resistance in the fields of biomedicine and therapeutics. The pathogen-killing ability of antimicrobial peptides (AMPs) is linked to their structure and physicochemical properties, including their conformation, electrical charges, hydrophilicity, and hydrophobicity. AMPs are a form of innate immune protection found in all life forms. A key aspect of the application of AMPs involves their potential to combat emerging antibiotic resistance; certain AMPs are effective against resistant microbial strains and can be modified through peptide engineering. This review summarizes the various strategies used to tackle antibiotic resistance, with a particular focus on the role of AMPs as effective antibiotic agents that enhance the host's immunological functions. Most of the recent studies on the properties and impregnation methods of AMPs, along with their biomedical applications, are discussed. This review provides researchers with insights into the latest advancements in AMP research, highlighting compelling evidence for the effectiveness of AMPs as antimicrobial agents.

Versatile Mechanically Tunable Hydrogels for Therapeutic Delivery Applications

Hydrogels provide a versatile platform for biomedical material fabrication that can be structurally and mechanically fine-tuned to various tissues and applications. Applications of hydrogels in biomedicine range from highly dynamic injectable hydrogels that can flow through syringe needles and maintain or recover their structure after extrusion to solid-like wound-healing patches that need to be stretchable while providing a selective physical barrier. In this study, a toolbox is designed using thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) polymeric matrices and nanocelluloses as reinforcing agent to obtain biocompatible hydrogels with altering mechanical properties, from a liquid injectable to a solid-like elastic hydrogel. The liquid hydrogels possess low viscosity and shear-thinning properties at 25 °C, which allows facile injection at room temperature, while they become viscoelastic gels at body temperature. In contrast, the covalently cross-linked solid-like hydrogels exhibit enhanced viscoelasticity. The liquid hydrogels are biocompatible and are able to delay the in vitro release and maintain the bioactivity of model drugs. The antimicrobial agent loaded solid-like hydrogels are effective against typical wound-associated pathogens. This work presents a simple method of tuning hydrogel mechanical strength to easily adapt to applications in different soft tissues and broaden the potential of renewable bio-nanoparticles in hybrid biomaterials with controlled drug release capabilities.

Light-degradable nanocomposite hydrogels for antibacterial wound dressing applications

Skin injuries infected by bacteria can cause life-threatening human diseases if not treated properly. In this work, we developed a light-degradable nanocomposite hydrogel to achieve both controlled antibiotic delivery and hydrogel degradation using light as the sole stimulus. Specifically, we incorporated triclosan-loaded, poly(N-isopropylacrylamide)-based nanogels (TCS-NGs) that exhibited potent antibacterial efficacy, into a light-degradable poly (ethylene glycol) (PEG)-based hydrogel matrix via simple physical entrapment method. Upon exposure to 365 nm light, the hydrogel matrix could rapidly degrade, which subsequently released the entrapped TCS-NGs into the surrounding environment. Our results demonstrated that TCS-NGs released from light-degradable nanocomposite hydrogels still possessed remarkable antibacterial efficacy by inhibiting the growth of Staphylococcus aureus both in solution (a fivefold reduction in optical density compared to the blank control) and on bacteria-infected porcine skins (a fivefold reduction in colony-forming units compared to the blank control). Finally, using an alamarBlue assay on human dermal fibroblasts, we determined that each component of the nanocomposite hydrogel exhibited excellent biocompatibility (>90% cell viability) and would not cause significant cytotoxicity. Overall, the fabricated light-degradable nanocomposite hydrogels could serve as novel material for antibacterial wound dressing applications.

Current status of development and biomedical applications of peptide-based antimicrobial hydrogels

Microbial contamination poses a serious threat to human life and health. Through the intersection of material science and modern medicine, advanced bionic hydrogels have shown great potential for biomedical applications due to their unique bioactivity and ability to mimic the extracellular matrix environment. In particular, as a promising antimicrobial material, the synthesis and practical biomedical applications of peptide-based antimicrobial hydrogels have drawn increasing research interest. The synergistic effect of peptides and hydrogels facilitate the controlled release of antimicrobial agents and mitigation of their biotoxicity while achieving antimicrobial effects and protecting the active agents from degradation. This review reports on the progress and trends of researches in the last five years and provides a brief outlook, aiming to provide theoretical background on peptide-based antimicrobial hydrogels and make suggestions for future related work.

Nanotechnological interventions in bacteriocin formulations - advances, and scope for challenging food spoilage bacteria and drug-resistant foodborne pathogens

Food spoilage bacteria (FSB) and multidrug-resistant (MDR) foodborne pathogens have emerged as one of the principal public health concerns in the twenty first century. The harmful effects of FSB lead to economic losses for the food industries. Similarly, MDR foodborne pathogens are accountable for multiple illnesses and pose a threat to consumers. Therefore, there is an urgent need to establish effective formulations for successful application against such microorganisms. In this context, the fusion of knowledge from biotechnology and nanotechnology can explore endless possibilities in the development of innovative formulations against FSB and foodborne pathogens. The current review critically examines the application of bacteriocins in the food industry and the use of nanomaterials to enhance the antimicrobial activity, stability, and precision in the target delivery of bacteriocins. This review also explores the technologies involved in the development of bacteriocin-based nanoformulations and their action against FSB and MDR foodborne pathogens, offering new possibilities in preservation technologies and addressing food safety issues in the food industry. The review highlights the challenges in the commercialization and technoeconomical feasibility of nanobacteriocin. Overall, it provides essential information and interpretation about nanotechnological advancements in bacteriocin formulation action against FSB and foodborne pathogens and future scopes.

Conjugation of antimicrobial peptides to enhance therapeutic efficacy

The growing prevalence of antimicrobial resistance (AMR) has brought with it a continual increase in the numbers of deaths from multidrug-resistant (MDR) infections. Since the current arsenal of antibiotics has become increasingly ineffective, there exists an urgent need for discovery and development of novel antimicrobials. Antimicrobial peptides (AMPs) are considered to be a promising class of molecules due to their broad-spectrum activities and low resistance rates compared with other types of antibiotics. Since AMPs also often play major roles in elevating the host immune response, the molecules may also be called "host defense peptides." Despite the great promise of AMPs, the majority remain unsuitable for clinical use due to issues of structural instability, degradation by proteases, and/or toxicity to host cells. Moreover, AMP activities in vivo can be influenced by many factors, such as interaction with blood and serum biomolecules, physiological salt concentrations or different pH values. To overcome these limitations, structural modifications can be made to the AMP. Among several modifications, physical and chemical conjugation of AMP to other biomolecules is widely considered an effective strategy. In this review, we discuss structural modification strategies related to conjugation of AMPs and their possible effects on mode of action. The conjugation of fatty acids, glycans, antibiotics, photosensitizers, polymers, nucleic acids, nanoparticles, and immobilization to biomaterials are highlighted.

Advancements and Applications of Injectable Hydrogel Composites in Biomedical Research and Therapy

Injectable hydrogels have gained popularity for their controlled release, targeted delivery, and enhanced mechanical properties. They hold promise in cardiac regeneration, joint diseases, postoperative analgesia, and ocular disorder treatment. Hydrogels enriched with nano-hydroxyapatite show potential in bone regeneration, addressing challenges of bone defects, osteoporosis, and tumor-associated regeneration. In wound management and cancer therapy, they enable controlled release, accelerated wound closure, and targeted drug delivery. Injectable hydrogels also find applications in ischemic brain injury, tissue regeneration, cardiovascular diseases, and personalized cancer immunotherapy. This manuscript highlights the versatility and potential of injectable hydrogel nanocomposites in biomedical research. Moreover, it includes a perspective section that explores future prospects, emphasizes interdisciplinary collaboration, and underscores the promising future potential of injectable hydrogel nanocomposites in biomedical research and applications.

Understanding the Role of Antimicrobial Peptides in Neutrophil Extracellular Traps Promoting Autoimmune Disorders

AMPs are small oligopeptides acting as integral elements of the innate immune system and are of tremendous potential in the medical field owing to their antimicrobial and immunomodulatory activities. They offer a multitude of immunomodulatory properties such as immune cell differentiation, inflammatory responses, cytokine production, and chemoattraction. Aberrancy in neutrophil or epithelial cell-producing AMPs leads to inflammation culminating in various autoimmune responses. In this review, we have tried to explore the role of prominent mammalian AMPs-defensins and cathelicidins, as immune regulators with special emphasis on their role in neutrophil extracellular traps which promotes autoimmune disorders. When complexed with self-DNA or self-RNA, AMPs act as autoantigens which activate plasmacytoid dendritic cells and myeloid dendritic cells leading to the production of interferons and cytokines. These trigger a series of self-directed inflammatory reactions, leading to the emergence of diverse autoimmune disorders. Since AMPs show both anti- and pro-inflammatory abilities in different ADs, there is a dire need for a complete understanding of their role before developing AMP-based therapy for autoimmune disorders.

S100 Proteins as Novel Therapeutic Targets in Psoriasis and Other Autoimmune Diseases

Psoriasis is one of the most common inflammatory skin diseases affecting about 1-3% of the population. One of the characteristic abnormalities in psoriasis is the excessive production of antimicrobial peptides and proteins, which play an essential role in the pathogenesis of the disease. Antimicrobial peptides and proteins can be expressed differently in normal and diseased skin, reflecting their usefulness as diagnostic biomarkers. Moreover, due to their very important functions in innate immunity, members of host defense peptides and proteins are currently considered to be promising new therapeutic targets for many inflammatory diseases. Koebnerisin (S100A15) belongs to an S100 family of antimicrobial proteins, which constitute the multigenetic group of calcium-binding proteins involved in ion-dependent cellular functions and regulation of immune mechanisms. S100A15 was first discovered to be overexpressed in 'koebnerized' psoriatic skin, indicating its involvement in the disease phenotype and the same promising potential as a new therapeutic target. This review describes the involvement of antimicrobial peptides and proteins in inflammatory diseases' development and therapy. The discussion focuses on S100 proteins, especially koebnerisin, which may be involved in the underlying mechanism of the Köebner phenomenon in psoriasis, as well as other immune-mediated inflammatory diseases described in the last decade.

Self-Healing Injectable Hydrogels for Tissue Regeneration

Biomaterials with the ability to self-heal and recover their structural integrity offer many advantages for applications in biomedicine. The past decade has witnessed the rapid emergence of a new class of self-healing biomaterials commonly termed injectable, or printable in the context of 3D printing. These self-healing injectable biomaterials, mostly hydrogels and other soft condensed matter based on reversible chemistry, are able to temporarily fluidize under shear stress and subsequently recover their original mechanical properties. Self-healing injectable hydrogels offer distinct advantages compared to traditional biomaterials. Most notably, they can be administered in a locally targeted and minimally invasive manner through a narrow syringe without the need for invasive surgery. Their moldability allows for a patient-specific intervention and shows great prospects for personalized medicine. Injected hydrogels can facilitate tissue regeneration in multiple ways owing to their viscoelastic and diffusive nature, ranging from simple mechanical support, spatiotemporally controlled delivery of cells or therapeutics, to local recruitment and modulation of host cells to promote tissue regeneration. Consequently, self-healing injectable hydrogels have been at the forefront of many cutting-edge tissue regeneration strategies. This study provides a critical review of the current state of self-healing injectable hydrogels for tissue regeneration. As key challenges toward further maturation of this exciting research field, we identify (i) the trade-off between the self-healing and injectability of hydrogels vs their physical stability, (ii) the lack of consensus on rheological characterization and quantitative benchmarks for self-healing injectable hydrogels, particularly regarding the capillary flow in syringes, and (iii) practical limitations regarding translation toward therapeutically effective formulations for regeneration of specific tissues. Hence, here we (i) review chemical and physical design strategies for self-healing injectable hydrogels, (ii) provide a practical guide for their rheological analysis, and (iii) showcase their applicability for regeneration of various tissues and 3D printing of complex tissues and organoids.

Antimicrobial Peptides: From Design to Clinical Application

Infection of multidrug-resistant (MDR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae (CRE), and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, brings public health issues and causes economic burden. Pathogenic bacteria develop several methods to resist antibiotic killing or inhibition, such as mutation of antibiotic function sites, activation of drug efflux pumps, and enzyme-mediated drug degradation. Antibiotic resistance components can be transferred between bacteria by mobile genetic elements including plasmids, transposons, and integrons, as well as bacteriophages. The development of antibiotic resistance limits the treatment options for bacterial infection, especially for MDR bacteria. Therefore, novel or alternative antibacterial agents are urgently needed. Antimicrobial peptides (AMPs) display multiple killing mechanisms against bacterial infections, including directly bactericidal activity and immunomodulatory function, as potential alternatives to antibiotics. In this review, the development of antibiotic resistance, the killing mechanisms of AMPs, and especially, the design, optimization, and delivery of AMPs are reviewed. Strategies such as structural change, amino acid substitution, conjugation with cell-penetration peptide, terminal acetylation and amidation, and encapsulation with nanoparticles will improve the antimicrobial efficacy, reduce toxicity, and accomplish local delivery of AMPs. In addition, clinical trials in AMP studies or applications of AMPs within the last five years were summarized. Overall, AMPs display diverse mechanisms of action against infection of pathogenic bacteria, and future research studies and clinical investigations will accelerate AMP application.