Mild Heat-Assisted Polydopamine/Alginate Hydrogel Containing Low-Dose Nanoselenium for Facilitating Infected Wound Healing

3D bioprinting of engineered exosomes secreted from M2-polarized macrophages through immunomodulatory biomaterial promotes in vivo wound healing and angiogenesis

Biomaterial composition and surface charge play a critical role in macrophage polarization, providing a molecular cue for immunomodulation and tissue regeneration. In this study, we developed bifunctional hydrogel inks for accelerating M2 macrophage polarization and exosome (Exo) cultivation for wound healing applications. For this, we first fabricated polyamine-modified three-dimensional (3D) printable hydrogels consisting of alginate/gelatin/polydopamine nanospheres (AG/NSPs) to boost M2-exosome (M2-Exo) secretion. The cultivated M2-Exo were finally encapsulated into a biocompatible collagen/decellularized extracellular matrix (COL@d-ECM) bioink for studying angiogenesis and in vivo wound healing study. Our findings show that 3D-printed AGP hydrogel promoted M2 macrophage polarization by Janus kinase/signal transducer of activation (JAK/STAT), peroxisome proliferator-activated receptor (PPAR) signaling pathways and facilitated the M2-Exo secretion. Moreover, the COL@d-ECM/M2-Exo was found to be biocompatible with skin cells. Transcriptomic (RNA-Seq) and real-time PCR (qRT-PCR) study revealed that co-culture of fibroblast/keratinocyte/stem cells/endothelial cells in a 3D bioprinted COL@d-ECM/M2-Exo hydrogel upregulated the skin-associated signature biomarkers through various regulatory pathways during epidermis remodeling and downregulated the mitogen-activated protein kinase (MAPK) signaling pathway after 7 days. In a subcutaneous wound model, the 3D bioprinted COL@d-ECM/M2-Exo hydrogel displayed robust wound remodeling and hair follicle (HF) induction while reducing canonical pro-inflammatory activation after 14 days, presenting a viable therapeutic strategy for skin-related disorders.

S-Alkylated sulfonium betulin derivatives: Synthesis, antibacterial activities, and wound healing applications

Betulin, a bioactive triterpenoid derived from Betulaceae bark with antimicrobial and anti-inflammatory properties, holds great potential as a therapeutic agent. In this work, cationic sulfonium-modified betulin derivatives were synthesized to enhance their antibacterial efficacy for wound healing application. Mono- and dual S-alkylated sulfonium derivatives significantly outperformed betulin in antibacterial activity against pathogens such as S. aureus, Methicillin-resistant S. aureus (MRSA), and E. coli. S-nonylated sulfonium betulin reduced the minimum inhibitory concentration of betulin against MRSA from 24 to 0.015 mM. The sulfonium modification enhanced cationic interactions, leading to bacterial membrane disruption. The derivatives expedited the process of wound healing by mitigating inflammation and exhibited satisfactory biosafety, proposing a viable approach to the development of antibacterial agents.

Application of Drug Delivery System Based on Nanozyme Cascade Technology in Chronic Wound

Chronic wounds are characterized by long-term inflammation, including diabetic ulcers, traumatic ulcers, etc., which provide an optimal environment for bacterial proliferation. At present, antibiotics are the main clinical treatment method for chronic wound infections. However, the overuse of antibiotics may accelerate the emergence of drug-resistant bacteria, which poses a significant threat to human health. Therefore, there is an urgent need to develop new therapeutic strategies for bacterial infections. Nanozyme-based antimicrobial therapy (NABT) is an emerging antimicrobial strategy with broad-spectrum activity and low drug resistance compared to traditional antibiotics. NABT has shown great potential as an emerging antimicrobial strategy by catalyzing the generation of reactive oxygen species (ROS) with its enzyme-like catalytic properties, producing a powerful bactericidal effect without developing drug resistance. Nanozyme-based cascade antimicrobial technology offers a new approach to infection control, effectively improving antimicrobial efficacy by activating cascades against bacterial cell membranes and intracellular DNA while minimizing potential side effects. However, it is worth noting that this technology is still in the early stages of research. This article comprehensively reviews wound classification, current methods for the treatment of wound infection, different types of nanozymes, the application of nanozyme cascade reaction technology in antimicrobial therapy, and future challenges and prospects.

Milk exosome-infused fibrous matrix for treatment of acute wound

To provide an advanced therapy for wound recovery, in this study, pasteurized bovine milk-derived exosomes (mEXO) are immobilized onto a polydopamine (PDA)-coated hyaluronic acid (HA)-based electrospun nanofibrous matrix (mEXO@PMAT) via a simple dip-coating method to formulate an mEXO-immobilized mesh as a wound-healing biomaterial. Purified mEXOs (∼82 nm) contain various anti-inflammatory, cell proliferation, and collagen synthesis-related microRNAs (miRNAs), including let-7b, miR-184, and miR-181a, which elicit elevated mRNA expression of keratin5, keratin14, and collagen1 in human keratinocytes (HaCaT) and fibroblasts (HDF). The mEXOs immobilized onto the PDA-coated meshes are gradually released from the meshes over 14 days without burst-out effect. After treatment with HaCaT and HDF, the degree of in vitro cell migration increases significantly in the mEXO@PMAT-treated HaCaT and HDF cells compared to the unmodified or PDA-coated meshes-treated cells. Additionally, the mEXO@PMAT provides significantly faster wound closure in vivo without notable toxicity. Thus, the sustained liberation of bioactive mEXO from the meshes can effectively enhance cell proliferation in vitro and accelerate wound closure in vivo, which could be harnessed mEXO@PMAT as a promising wound-healing biomaterial.

Bioinspired Wearable Hydrogel Composite with Sustained Drug-Release for Wound Healing and Naked-Eye Visual Early Warning of Wound Dehiscence

Wound healing is critical to the structural and functional restoration of damaged tissue. However, effective wound closure and healing are always great challenges in regenerative engineering. This study provided bioinspired wearable hydrogel composites with drug-releasing hydrogel and nonclose-packed photonic crystals (NPCs) for wound therapy and naked-eye visual early warning of wound dehiscence. Molecular dynamics models and drug-releasing results illustrated the sustained drug release of ibuprofen, and the mechanical properties of the drug-releasing hydrogel were optimized with 1410% tensile strain by introducing fish collagen; their biocompatibility and adhesion were also improved. The structural color of the NPCs blue-shifted from 630 to 500 nm with 15.0% strain, and the original color was customized with poly(methyl methacrylate) (PMMA) concentration and acrylamide content. Compared with the gauze and the traditional hydrogels, the composite provided a moist environment and an effectively closed wound; the debridement and released drug avoided inflammation, and the rat wound was healed 40.5% on the third day and essentially 100% on the 14th day. The work provided a novel strategy for wound healing and naked-eye visual early warning when a wound deforms, which is expected to promote the synergistic development of clinical treatment and visualized early warning.

Injectable polyamide-amine dendrimer-crosslinked meloxicam-containing poly-γ-glutamic acid hydrogel for prevention of postoperative tissue adhesion through inhibiting inflammatory responses and balancing the fibrinolytic system

Establishing a physical barrier between the peritoneum and the cecum is an effective method to reduce the risk of postoperative abdominal adhesions. Meloxicam (MX), a nonsteroidal anti-inflammatory drug has also been applied to prevent postoperative adhesions. However, its poor water solubility has led to low bioavailability. Herein, we developed an injectable hydrogel as a barrier and drug carrier for simultaneous postoperative adhesion prevention and treatment. A third-generation polyamide-amine dendrimer (G3) was exploited to dynamically combine with MX to increase the solubility and the bioavailability. The formed G3@MX was further used to crosslink with poly-γ-glutamic acid (γ-PGA) to prepare a hydrogel (GP@MX hydrogel) through the amide bonding. In vitro and in vivo experiments evidenced that the hydrogel had good biosafety and biodegradability. More importantly, the prepared hydrogel could control the release of MX, and the released MX is able to inhibit inflammatory responses and balance the fibrinolytic system in the injury tissues in vivo. The tunable rheological and mechanical properties (compressive moduli: from ∼ 57.31 kPa to ∼ 98.68 kPa;) and high anti-oxidant capacity (total free radical scavenging rate of ∼ 94.56 %), in conjunction with their syringeability and biocompatibility, indicate possible opportunities for the development of advanced hydrogels for postoperative tissue adhesions management.

A Hydrogel Dressing Comprised of Silk Fibroin, Ag Nanoparticles, and Reduced Graphene Oxide for NIR Photothermal-Enhanced Antibacterial Efficiency and Skin Regeneration

Bacterial infection, inflammation, and excessive oxidative stress are the primary factors that contribute to delayed healing of skin wounds. In this study, a multifunctional wound dressing (SF/Ag@rGO hydrogel) is developed to promote the healing of infected skin wounds by combining the inherent antibacterial activity of Ag nanoparticles (NPs) with near-infrared (NIR)-assisted antibacterial therapy. Initially, L-ascorbic acid is used as a reducing agent and PVP-K17 as a stabilizer and dispersant, this facilitates the synthesis of reduced graphene oxide loaded with Ag NPs (Ag@rGO). Ag@rGO is then blended with a silk fibroin (SF) solution to form an instantly gelling SF/Ag@rGO hydrogel that exhibits rapid self-healing, injectability, shape adaptability, NIR responsiveness, antioxidant, high tissue adhesion, and robust mechanical properties. In vitro and in vivo experiments show that the SF/Ag@rGO hydrogel demonstrates strong antioxidant and photothermal antibacterial capabilities, promoting wound healing through angiogenesis, stimulating collagen generation, alleviating inflammation, antioxidant, and promoting cell proliferation, indicating that the SF/Ag@rGO hydrogel dressing is an ideal candidate for clinical treatment of full-thickness bacterial-stained wounds.

Mechanism Analysis of Selenium-Containing Compounds in Alleviating Spinal Cord Injury Based on Network Pharmacology and Molecular Docking Technology

Spinal cord injury (SCI) is a severe traumatic condition in spinal surgery characterized by nerve damage in and below the injured area. Despite advancements in understanding the pathophysiology of SCI, effective clinical treatments remain elusive. Selenium compounds have become a research hotspot due to their diverse medicinal activities. Previously, our group synthesized a selenium-containing Compound 34# with significant anti-inflammatory activity. This study aimed to explore the anti-SCI effects of selenium-containing compounds using network pharmacology, molecular docking (MD), and ADMET methods. To identify SCI-related targets and those associated with 34#, GeneCards, NCBI, and SEA databases were employed. Eight overlapping targets were considered candidate targets, and molecular docking was performed using the PDB database and AutoDock software. The STRING database was used to obtain protein-protein interactions (PPI). Molecular dynamics simulation, MM/GBSA binding free energy score, and ADMET prediction were used to evaluate the potential targets and drug properties of 34#. Finally, experiments on NSC34 cells and mice were to verify the effects of 34# on SCI. Our results revealed eight candidate targets for 34# in the treatment of SCI. PPI and MD identified ADRB2 and HTR1F as the highest connectivity with 34#. ADMET analysis confirmed the low toxicity and safety of 34#. In vitro and in vivo models validated the anti-SCI effects. Our study elucidated candidate targets for alleviating SCI with 34#, explored PPI and target-related signaling pathways, and validated its anti-SCI effects. These findings enhance our understanding of 34#'s mechanism in treating SCI, positioning it as a potential candidate for SCI prevention.

Molybdenum Disulfide-Supported Cuprous Oxide Nanocomposite for Near-Infrared-I Light-Responsive Synergistic Antibacterial Therapy

Drug-resistant bacterial infections pose a serious threat to human health; thus, there is an increasingly growing demand for nonantibiotic strategies to overcome drug resistance in bacterial infections. Mild photothermal therapy (PTT), as an attractive antibacterial strategy, shows great potential application due to its good biocompatibility and ability to circumvent drug resistance. However, its efficiency is limited by the heat resistance of bacteria. Herein, Cu2O@MoS2, a nanocomposite, was constructed by the in situ growth of Cu2O nanoparticles (NPs) on the surface of MoS2 nanosheets, which provided a controllable photothermal therapeutic effect of MoS2 and the intrinsic catalytic properties of Cu2O NPs, achieving a synergistic effect to eradicate multidrug-resistant bacteria. Transcriptome sequencing (RNA-seq) results revealed that the antibacterial process was related to disrupting the membrane transport system, phosphorelay signal transduction system, oxidative stress response system, as well as the heat response system. Animal experiments indicated that Cu2O@MoS2 could effectively treat wounds infected with methicillin-resistant Staphylococcus aureus. In addition, satisfactory biocompatibility made Cu2O@MoS2 a promising antibacterial agent. Overall, our results highlight the Cu2O@MoS2 nanocomposite as a promising solution to combating resistant bacteria without inducing the evolution of antimicrobial resistance.

CuCS/Cur composite wound dressings promote neuralized skin regeneration by rebuilding the nerve cell "factory" in deep skin burns

Regenerating skin nerves in deep burn wounds poses a significant clinical challenge. In this study, we designed an electrospun wound dressing called CuCS/Cur, which incorporates copper-doped calcium silicate (CuCS) and curcumin (Cur). The unique wound dressing releases a bioactive Cu2+-Cur chelate that plays a crucial role in addressing this challenge. By rebuilding the "factory" (hair follicle) responsible for producing nerve cells, CuCS/Cur induces a high expression of nerve-related factors within the hair follicle cells and promotes an abundant source of nerves for burn wounds. Moreover, the Cu2+-Cur chelate activates the differentiation of nerve cells into a mature nerve cell network, thereby efficiently promoting the reconstruction of the neural network in burn wounds. Additionally, the Cu2+-Cur chelate significantly stimulates angiogenesis in the burn area, ensuring ample nutrients for burn wound repair, hair follicle regeneration, and nerve regeneration. This study confirms the crucial role of chelation synergy between bioactive ions and flavonoids in promoting the regeneration of neuralized skin through wound dressings, providing valuable insights for the development of new biomaterials aimed at enhancing neural repair.

Multifunctional nanoplatform based on tetragonal BaTiO3-Au@polydopamine for computed tomography imaging-guided photothermal synergistic and enhanced piezocatalytic cancer therapy

Non-centrosymmetric tetragonal barium titanate nanocrystals have the potential to serve as piezoelectric catalysts in cancer therapy. When exposed to ultrasound irradiation, BaTiO3 can generate reactive oxygen species with a noninvasive and deep tissue-penetrating approach. However, the application of BaTiO3 in cancer nanomedicine is limited by their biosafety, biocompatibility, and dosage efficiency. To explore the potential application of BaTiO3 in nanomedical cancer treatment, we introduced ultra-small Au nanoparticles onto the surface of BaTiO3 to enhance the piezoelectric catalytic performance. Additionally, we also coated the BaTiO3 with polydopamine to improve their biosafety and biocompatibility. This led to the preparation of a novel multifunctional BaTiO3-based nanoplatform called BTAPs. In vitro and in vivo experiments demonstrated that the incorporation of Au dopants and polydopamine coating successfully improved the piezoelectric catalysis properties and biocompatibility of BaTiO3. Compared with unmodified BaTiO3, BTAPs achieved a similar piezoelectric catalytic effect at a low dose (0.3 mg ml-1 in vitro and 10 mg kg-1 in vivo). Moreover, BTAPs also exhibited enhanced properties in computed tomography imaging and photothermal effects in vivo. Therefore, BTAPs offer valuable insights into the advantages and limitations of piezoelectric catalytic nanomedicine in cancer treatment.

Janus silk fibroin/polycaprolactone-based scaffold with directionally aligned fibers and porous structure for bone regeneration

To promote bone repair, it is desirable to develop three-dimensional multifunctional fiber scaffolds. The densely stacked and tightly arranged conventional two-dimensional electrospun fibers hinder cell penetration into the scaffold. Most of the existing three-dimensional structural materials are isotropic and monofunctional. In this research, a Janus nanofibrous scaffold based on silk fibroin/polycaprolactone (SF/PCL) was fabricated. SF-encapsulated SeNPs demonstrated stability and resistance to aggregation. The outside layer (SF/PCL/Se) of the Janus nanofiber scaffold displayed a structured arrangement of fibers, facilitating cell growth guidance and impeding cell invasion. The inside layer (SF/PCL/HA) featured a porous structure fostering cell adhesion. The Janus fiber scaffold containing SeNPs notably suppressed S. aureus and E. coli activities, correlating with SeNPs concentration. In vitro, findings indicated considerable enhancement in alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts and upregulation of genes linked to osteogenic differentiation with exposure to the SF/PCL/HA/Se Janus nanofibrous scaffold. Moreover, in vivo, experiments demonstrated successful critical bone defect repair in mouse skulls using the SF/PCL/HA/Se Janus nanofiber scaffold. These findings highlight the potential of the SF/PCL-based Janus nanofibrous scaffold, integrating SeNPs and nHA, as a promising biomaterial in bone tissue engineering.

pH-Responsive Wound Dressing Based on Biodegradable CuP Nanozymes for Treating Infected and Diabetic Wounds

Nanozymes, emerging nanomaterials for wound healing, exhibit enzyme-like activity to modulate the levels of reactive oxygen species (ROS) at wound sites. Yet, the solo regulation of endogenous ROS by nanozymes often falls short, particularly in chronic refractory wounds with complex and variable pathological microenvironments. In this study, we report the development of a multifunctional wound dressing integrating a conventional alginate (Alg) hydrogel with a newly developed biodegradable copper hydrogen phosphate (CuP) nanozyme, which possesses good near-infrared (NIR) photothermal conversion capabilities, sustained Cu ion release ability, and pH-responsive peroxidase/catalase-mimetic catalytic activity. When examining acute infected wounds characterized by a low pH environment, the engineered Alg/CuP composite hydrogels demonstrated high bacterial eradication efficacy against both planktonic bacteria and biofilms, attributed to the combined action of catalytically generated hydroxyl radicals and the sustained release of Cu ions. In contrast, when applied to chronic diabetic wounds, which typically have a high pH environment, these composite hydrogels exhibit significant angiogenic performance. This is driven by the provision of catalytically generated dissolved oxygen and a beneficial supplement of Cu ions released from the degradable CuP nanozyme. Further, a mild thermal effect induced by NIR irradiation amplifies the catalytic activities and bioactivity of Cu ions, thereby enhancing the healing process of both infected and diabetic wounds. Our study validates that the synergistic integration of photothermal effects, catalytic activity, and released Cu ions can concurrently yield high antibacterial efficiency and tissue regenerative activity, rendering it highly promising for various clinical applications in wound healing.

TiB2-Derived Nanosheets Enhance the Tensile Strength and Controlled Drug Release of Biopolymeric Films Used in Wound Healing

Wound healing using an alginate-based biopolymeric film is one of the most preferred treatments. However, these films lack mechanical strength (elasticity and tensile strength), show higher initial burst release, and exhibit high vapor permeability. The present study reports the development of nanosheets derived from titanium diboride (10 nm) (NTB)-incorporated biopolymeric films (0.025, 0.05, and 0.1% w/v) using sodium alginate (SA) and carboxymethyl cellulose (CMC) to overcome the shortfalls. The surface properties of the film, nanosheet distribution within the film, and possible interactions with the film are explored by using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). These analyses confirm that nanosheets are uniformly distributed in the film and introduce unevenness on the film's surface. The tensile strength of the nanosheet-incorporated film (0.1% NTB film) using UTM is found to be 24.30 MPa (six times higher compared to the blank film), equivalent to human skin. The water vapor transmission rate of the film is also found to be in the desired range (i.e., 2000-2500 g/m2 day). The biocompatibility of the NTB film is confirmed by the MTT assay test using NIH/3T3 cells and HEK 293 cells. Furthermore, the scratch assay shows that the developed films promote cell migration and proliferation. The antibacterial activity of the film is also demonstrated using a model drug, tetracycline hydrochloride (TCl). Besides, the film exhibits the sustained release of TCl and follows the Korsmeyer-Peppas model for drug release. Overall, the 0.1% w/v NTB film is easy to fabricate, biocompatible and shows superior mechanical properties.

Functional drug-delivery hydrogels for oral and maxillofacial wound healing

The repair process for oral and maxillofacial injuries involves hemostasis, inflammation, proliferation, and remodeling. Injury repair involves a variety of cells, including platelets, immune cells, fibroblasts, and various cytokines. Rapid and adequate healing of oral and maxillofacial trauma is a major concern to patients. Functional drug-delivery hydrogels play an active role in promoting wound healing and have shown unique advantages in wound dressings. Functional hydrogels promote wound healing through their adhesive, anti-inflammatory, antioxidant, antibacterial, hemostatic, angiogenic, and re-epithelialization-promoting properties, effectively sealing wounds and reducing inflammation. In addition, functional hydrogels can respond to changes in temperature, light, magnetic fields, pH, and reactive oxygen species to release drugs, enabling precise treatment. Furthermore, hydrogels can deliver various cargos that promote healing, including nucleic acids, cytokines, small-molecule drugs, stem cells, exosomes, and nanomaterials. Therefore, functional drug-delivery hydrogels have a positive impact on the healing of oral and maxillofacial injuries. This review describes the oral mucosal structure and healing process and summarizes the currently available responsive hydrogels used to promote wound healing.

Natural biomarocmolecule-based antimicrobial hydrogel for rapid wound healing: A review

Antibacterial hydrogels are a type of hydrogel that is designed to inhibit the growth of bacteria and prevent infections. These hydrogels typically contain antibacterial agents that are either integrated into the polymer network or coated onto the surface of the hydrogel. The antibacterial agents in these hydrogels can work through a variety of mechanisms, such as disrupting bacterial cell walls or inhibiting bacterial enzyme activity. Some examples of antibacterial agents that are commonly used in hydrogels include silver nanoparticles, chitosan, and quaternary ammonium compounds. Antibacterial hydrogels have a wide range of applications, including wound dressings, catheters, and medical implants. They can help to prevent infections, reduce inflammation, and promote tissue healing. In addition, they can be designed with specific properties to suit different applications, such as high mechanical strength or controlled release of antibacterial agents over time. Hydrogel wound dressings have come a long way in recent years, and the future looks very promising for these innovative wound care products. Overall, the future of hydrogel wound dressings is very promising, and we can expect to see continued innovation and advancement in this field in the years to come.

Layer-by-Layer Microneedle-Mediated rhEGF Transdermal Delivery for Enhanced Wound Epidermal Regeneration and Angiogenesis

Appropriate treatments for acute traumas tend to avoid hemorrhages, vascular damage, and infections. However, in the homeostasis-imbalanced wound microenvironment, currently developed therapies could not precisely and controllably deliver biomacromolecular drugs, which are confronted with challenges due to large molecular weight, poor biomembrane permeability, low dosage, rapid degradation, and bioactivity loss. To conquer this, we construct a simple and effective layer-by-layer (LBL) self-assembly transdermal delivery patch, bearing microneedles (MN) coated with recombinant human epidermal growth factor (LBL MN-rhEGF) for a sustained release to wound bed driven by typical electrostatic force. Pyramidal LBL MN-rhEGF patches hold so enough mechanical strength to penetrate the stratum corneum, and generated microchannels allow rhEGF direct delivery in situ. The administrable delivery of biomacromolecular rhEGF through hierarchically coated MN arrays follows the diffusion mechanism of Fick's second law. Numerous efforts further have illustrated that finger-pressing LBL MN-rhEGF patches could not only promote cell proliferation of normal human dermal fibroblasts (NHDF) and human umbilical vein endothelial cells (HUVEC) in vitro but also take significant effects (regenerative epidermis: ∼144 μm; pro-angiogenesis: higher CD31 expression) in accelerating wound healing of mechanically injured rats, compared to the traditional dressing, which relies on passive diffusion. Our proof-of-concept features novel LBL biomacromolecular drug-delivery systems and self-administrated precision medicine modes at the point of care.