Biomimetic Elastomeric Polypeptide-Based Nanofibrous Matrix for Overcoming Multidrug-Resistant Bacteria and Enhancing Full-Thickness Wound Healing/Skin Regeneration

Intrinsically bioactive multifunctional Poly(citrate-curcumin) for rapid lung injury and MRSA infection therapy

Dysregulated inflammation after trauma or infection could result in the further disease and delayed tissue reconstruction. The conventional anti-inflammatory drug treatment suffers to the poor bioavailability and side effects. Herein, we developed an amphiphilic multifunctional poly (citrate-polyglycol-curcumin) (PCGC) nano oligomer with the robust anti-inflammatory activity for treating acute lung injury (ALI) and Methicillin-resistant staphylococcus aureus (MRSA) infected wound. PCGC demonstrated the sustained curcumin release, inherent photoluminescence, good cellular compatibility, hemocompatibility, robust antioxidant activity and enhanced cellular uptake. PCGC could efficiently scavenge nitrogen-based free radicals, oxygen-based free radicals, and intracellular oxygen species, enhance the endothelial cell migration and reduce the expression of pro-inflammatory factors through the NF-κB signal pathway. Combined the anti-inflammation and antioxidant properties, PCGC can shortened the inflammatory process. In animal model of ALI, PCGC was able to reduce the pulmonary edema, bronchial cell infiltration, and lung inflammation, while exhibiting rapid metabolic behavior in vivo. The MRSA-infection wound model showed that PCGC significantly reduced the expression of pro-inflammatory factors, promoted the angiogenesis and accelerated the wound healing. The transcriptome sequencing and molecular mechanism studies further demonstrated that PCGC could inhibit multiple inflammatory related pathways including TNFAIP3, IL-15RA, NF-κB. This work demonstrates that PCGC is efficient in resolving inflammation and promotes the prospect of application in inflammatory diseases as the drug-loaded therapeutic system.

Citric Acid: A Nexus Between Cellular Mechanisms and Biomaterial Innovations

Citrate-based biodegradable polymers have emerged as a distinctive biomaterial platform with tremendous potential for diverse medical applications. By harnessing their versatile chemistry, these polymers exhibit a wide range of material and bioactive properties, enabling them to regulate cell metabolism and stem cell differentiation through energy metabolism, metabonegenesis, angiogenesis, and immunomodulation. Moreover, the recent US Food and Drug Administration (FDA) clearance of the biodegradable poly(octamethylene citrate) (POC)/hydroxyapatite-based orthopedic fixation devices represents a translational research milestone for biomaterial science. POC joins a short list of biodegradable synthetic polymers that have ever been authorized by the FDA for use in humans. The clinical success of POC has sparked enthusiasm and accelerated the development of next-generation citrate-based biomaterials. This review presents a comprehensive, forward-thinking discussion on the pivotal role of citrate chemistry and metabolism in various tissue regeneration and on the development of functional citrate-based metabotissugenic biomaterials for regenerative engineering applications.

Nanotechnology in tissue engineering: expanding possibilities with nanoparticles

Tissue engineering is a multidisciplinary field that merges engineering, material science, and medical biology in order to develop biological alternatives for repairing, replacing, maintaining, or boosting the functionality of tissues and organs. The ultimate goal of tissue engineering is to create biological alternatives for repairing, replacing, maintaining, or enhancing the functionality of tissues and organs. However, the current landscape of tissue engineering techniques presents several challenges, including a lack of suitable biomaterials, inadequate cell proliferation, limited methodologies for replicating desired physiological structures, and the unstable and insufficient production of growth factors, which are essential for facilitating cell communication and the appropriate cellular responses. Despite these challenges, there has been significant progress made in tissue engineering techniques in recent years. Nanoparticles hold a major role within the realm of nanotechnology due to their unique qualities that change with size. These particles, which provide potential solutions to the issues that are met in tissue engineering, have helped propel nanotechnology to its current state of prominence. Despite substantial breakthroughs in the utilization of nanoparticles over the past two decades, the full range of their potential in addressing the difficulties within tissue engineering remains largely untapped. This is due to the fact that these advancements have occurred in relatively isolated pockets. In the realm of tissue engineering, the purpose of this research is to conduct an in-depth investigation of the several ways in which various types of nanoparticles might be put to use. In addition to this, it sheds light on the challenges that need to be conquered in order to unlock the maximum potential of nanotechnology in this area.

Robust Gradient Hydrogel-Loaded Nanofiber Fleshy Artificial Skin Via A Coupled Microfluidic Electrospinning-Reactive Coating Strategy

Skin regeneration attracts tremendous interest due to the important role of skin for human protection and beauty. Thus, methods allowing artificial skin to be carried out in a controllable fashion are potentially important for wound healing, which involves an intersection of materials, medicine, biology, and other disciplines. Herein, aiming at a new general methodology for fleshy materials, a new hydrogel-loaded hydrophobic-hydrophilic nanofiber fleshy artificial skin is designed and fabricated. The gradient hydrogel-loaded nanofiber artificial skin integrates both advantages of nanofiber and hydrogel, exhibiting fleshy feature (comparability to real skin in terms of appearance, texture, and function), excellent air permeability, compatibility, and good mechanical and antibacterial property. Interestingly, the efficient transport channels are formed throughout the hydrogel-loaded nanofiber structure, which is beneficial for water absorption and transfer. These advantages enable the establishment of a moist and favorable microenvironment; thus, greatly accelerating wound healing process. This work couples microfluidic electrospinning with reactive coating technique, which is in favor of material design and fabrication with controllable and uniform structures. The hydrogel-loaded nanofiber fleshy artificial skin shows comparability to real skin in terms of beauty, texture, and function, which would definitely provide new opportunities for the further optimization and upgrading of artificial skin.

Multifunctional Drug- and AuNRs-Loaded ROS-Responsive Selenium-Containing Polyurethane Nanofibers for Smart Wound Healing

Elevated levels of ROS, bacterial infection, inflammation, and improper regeneration are the factors that need to be addressed simultaneously for achieving effective wound healing without scar formation. This study focuses on the fabrication of electrospun ROS-responsive selenium-containing polyurethane nanofibers incorporating deferoxamine mesylate (Def), indomethacin (Indo), and gold nanorods (AuNRs) as proangiogenesis, anti-inflammatory, and antibacterial agents for synchronized delivery to a full-thickness wound in vivo. The structure of the fabricated nanofibers was analyzed by various techniques. Toxicity was checked by CCK-8 and hemolytic assays. The efficiency of wound healing in vitro was verified by a transwell assay and cell scratch assay. The wound healing efficiency of the nanofibers was assayed in full-thickness wounds in a rat model. The multifunctional nanofibers had a porous structure, enhanced antioxidation, antibacterial activity, and promoted wound healing. They eradicated TNF-α and IL-6, increased IL-10 expression, and revealed the angiogenic potential by increased expression of HIF-1α, VEGF, and CD31.

Biomimetic Materials for Skin Tissue Regeneration and Electronic Skin

Biomimetic materials have become a promising alternative in the field of tissue engineering and regenerative medicine to address critical challenges in wound healing and skin regeneration. Skin-mimetic materials have enormous potential to improve wound healing outcomes and enable innovative diagnostic and sensor applications. Human skin, with its complex structure and diverse functions, serves as an excellent model for designing biomaterials. Creating effective wound coverings requires mimicking the unique extracellular matrix composition, mechanical properties, and biochemical cues. Additionally, integrating electronic functionality into these materials presents exciting possibilities for real-time monitoring, diagnostics, and personalized healthcare. This review examines biomimetic skin materials and their role in regenerative wound healing, as well as their integration with electronic skin technologies. It discusses recent advances, challenges, and future directions in this rapidly evolving field.

Carboxymethyl chitosan-based hydrogel-Janus nanofiber scaffolds with unidirectional storage-drainage of biofluid for accelerating full-thickness wound healing

Self-pumping wound scaffolds designed for directional biofluid transport are extensively investigated. They efficiently extract excessive biofluids from wounds, while maintaining an optimally humid wound environment, thus facilitating rapid wound healing. However, the existing designed scaffolds are insufficiently focused on stimulating the hydrophobic layer at the wound site, thereby exacerbating inflammation and impeding the wound healing process. Herein, we engineered and fabricated a hydrophilic-hydrophobic-hydrophilic sandwich-structured hydrogel-Janus nanofiber scaffold (NFS) employing a Layer-by-Layer (LbL) method. This scaffold comprises a hydrophilic carboxymethyl chitosan/silver (CMCS-Ag) hydrogel component in conjunction with a poly(caprolactone)/poly(caprolactone)-poly(citric acid)-co-ε-polylysine (PCL/PCL-PCE) Janus NFS. It is noteworthy that the hydrogel-Janus nanofiber scaffold not only demonstrates outstanding water absorption (202.2 %) and unidirectional biofluid transport capability but also possesses high breathability (308.663 m3/m2 h kPa), appropriate pore size (6.7-7.5 μm), excellent tensile performance (270 ± 10 %), and superior mechanical strength (26.36 ± 1.77 MPa). Moreover, in vitro experimentation has convincingly demonstrated the impeccable biocompatibility of hydrogel-Janus NFS. The inherent dual-antibacterial properties in CMCS-Ag and PCE significantly augment fibroblast proliferation and migration. In vivo studies further underscore its capability to expedite wound healing by absorption and expulsion of wound exudates, thereby fostering collagen deposition and vascularization. As such, this work potentially provides fresh insights into the design and fabrication of multifunctional biomimetic scaffolds, holding immense potential in the medical field for efficient wound healing.

A novel bola-molecular self-assembling hydrogel for enhancing diabetic wound healing

HYPOTHESIS

Chronic wounds, particularly those caused by diabetes, pose a significant challenge for clinical treatment due to their prolonged healing process and associated complications, which can lead to increased morbidity. A biocompatible hydrogel with strong antibacterial properties and the ability to promote angiogenesis can be directly absorbed in the wound site for healing.

EXPERIMENTS

A series of self-healing, antibacterial bolaamphiphilic supramolecular self-assembling hydrogels (HLQMes/Cu) were developed based on metal-ligand coordination between various concentrations of Cu2+ solution and the head group of l-histidine methyl ester in HLQMes. This is the first report on the application of bola-molecular supramolecular hydrogels for the treatment of chronic wounds.

FINDINGS

The bola-molecular hydrogels reduced the toxicity of copper ions by coordination, and the HLQMes/Cu hydrogel, with 1.3 mg/mL Cu2+ (HLQMes/Cu1.3), demonstrated good biocompatibility and antibacterial properties and effectively enhanced wound healing in a diabetic wound model with full-thickness injuries. Immunohistochemical analysis revealed that the HLQMes/Cu1.3 hydrogel enhanced epithelial formation and collagen deposition in wounds. Immunofluorescence studies confirmed that the HLQMes/Cu1.3 hydrogel attenuated the expression of proinflammatory factor (IL-6) and promoted angiogenesis by upregulating α-SMA and CD31. These findings demonstrate the potential of this bolaamphiphilic supramolecular self-assembling hydrogel as a promising candidate for diabetic wound treatment.

Photothermal and Photocatalytic Glycol Chitosan and Polydopamine-Grafted Oxygen Vacancy Bismuth Oxyiodide (BiO1-x I) Nanoparticles for the Diagnosis and Targeted Therapy of Diabetic Wounds

Treatment of diabetic wounds is a significant clinical challenge due to the massive infections caused by bacteria. In this study, multifunctional glycol chitosan and polydopamine-coated BiO1-x I (GPBO) nanoparticles (NPs) with near-infrared (NIR) photothermal and photocatalytic abilities are prepared. When infection occurs, the local microenvironment becomes acidic, and the pH-switchable GPBO can target the bacteria of the wound site. The NIR-assisted GPBO treatment exhibits anti-bacterial effects with fast response, high efficiency, and long duration to Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. GPBO achieves excellent photothermal imaging and CT imaging of the mouse subcutaneous abscess model. With the assistance of NIR irradiation, the GPBO promotes the healing of the diabetic wound model with the effects of anti-bacteria, anti-inflammation, the M2 polarization promotion of macrophages, and angiogenesis. This is the first-time report of nano-sized BiO1-x I. The synthesis and selected application for the imaging and targeted therapy of diabetic wounds are presented. This study offers an example of the NP-assisted precise diagnosis and therapy of bacterial infection diseases.

Solution blow spun bilayer chitosan/polylactic acid nanofibrous patch with antibacterial and anti-inflammatory properties for accelerating acne healing

The quercetin (QC) loaded chitosan (CS) nanofibrous patch (CSQC) was designed and fabricated successfully by solution blow spinning (SBS). And it was employed to explore a functional double-layer nanofibrous patch (CSQC/PLA) with polylactic acid (PLA) for overcoming the resistance of acne-causing bacteria to antibiotics and local cutaneous irritation. The nanofibrous patch possessed a fluffy bilayer structure with good air permeability, which may be befitted from the SBS method. The 10 % QC loaded CSQC0.10/PLA had sustained release ability of QC for 24 h. A high free radical clearance rate (91.18 ± 2.26 %) and robust antibacterial activity against P. acnes (94.4 %) were achieved for CSQC0.10/PLA with excellent biocompatibility. Meanwhile, E. coli and S. aureus were also suppressed with 99.4 % and 99.2 %, respectively. Moreover, the expression of pro-inflammatory cytokines (IL-6 and TNF-α) was significantly reduced, conducive to acne healing. Therefore, the CSQC0.10/PLA bilayer nanofibrous patch designed here may shed some light on developing multifunctional materials for treating acne infectious wounds.

Neutrophil Function Conversion Driven by Immune Switchpoint Regulator against Diabetes-Related Biofilm Infections

Reinforced biofilm structures and dysfunctional neutrophils induced by excessive oxidative stress contribute to the refractoriness of diabetes-related biofilm infections (DRBIs). Herein, in contrast to traditional antibacterial therapies, an immune switchpoint-driven neutrophil immune function conversion strategy based on a deoxyribonuclease I loaded vanadium carbide MXene (DNase-I@V2 C) nanoregulator is proposed to treat DRBIs via biofilm lysis and redirecting neutrophil functions from NETosis to phagocytosis in diabetes. Owing to its intrinsic superoxide dismutase/catalase-like activities, DNase-I@V2 C effectively scavenges reactive oxygen species (ROS) in a high oxidative stress microenvironment to maintain the biological activity of DNase-I. By increasing the depth of biofilm penetration of DNase-I, DNase-I@V2 C thoroughly degrades extracellular DNA and neutrophil extracellular traps (NETs) in extracellular polymeric substances, thus breaking the physical barrier of biofilms. More importantly, as an immune switchpoint regulator, DNase-I@V2 C can skew neutrophil functions from NETosis toward phagocytosis by intercepting ROS-NE/MPO-PAD4 and activating ROS-PI3K-AKT-mTOR pathways in diabetic microenvironment, thereby eliminating biofilm infections. Biofilm lysis and synergistic neutrophil function conversion exert favorable therapeutic effects on biofilm infections in vitro and in vivo. This study serves as a proof-of-principle demonstration of effectively achieving DRBIs with high therapeutic efficacy by regulating immune switchpoint to reverse neutrophil functions.

Enabling Proregenerative Medical Devices via Citrate-Based Biomaterials: Transitioning from Inert to Regenerative Biomaterials

Regenerative medicine aims to restore tissue and organ function without the use of prosthetics and permanent implants. However, achieving this goal has been elusive, and the field remains mostly an academic discipline with few products widely used in clinical practice. From a materials science perspective, barriers include the lack of proregenerative biomaterials, a complex regulatory process to demonstrate safety and efficacy, and user adoption challenges. Although biomaterials, particularly biodegradable polymers, can play a major role in regenerative medicine, their suboptimal mechanical and degradation properties often limit their use, and they do not support inherent biological processes that facilitate tissue regeneration. As of 2020, nine synthetic biodegradable polymers used in medical devices are cleared or approved for use in the United States of America. Despite the limitations in the design, production, and marketing of these devices, this small number of biodegradable polymers has dominated the resorbable medical device market for the past 50 years. This perspective will review the history and applications of biodegradable polymers used in medical devices, highlight the need and requirements for regenerative biomaterials, and discuss the path behind the recent successful introduction of citrate-based biomaterials for manufacturing innovative medical products aimed at improving the outcome of musculoskeletal surgeries.

Chicoric acid inserted in protein Z cavity exhibits higher stability and better wound healing effect under oxidative stress

Oxidative stress is one of the limiting factors that inhibit wound healing. Phytochemicals especially chicoric acid have the potential to act as an antioxidant and scavenge reactive oxygen species, thereby promoting wound healing. However, most of the phytochemicals were easy to be degraded during storage or using due to the oxidative status in wound site. Herein, we introduce a high stable protein Z that can encapsulate chicoric acid during foaming. TEM results showed that the size of protein Z-chicoric acid is in the range of nanoscale (named PZ-CA nanocomposite), and protein Z encapsulation can significantly improve the stability of chicoric acid under oxidative stress. Moreover, PZ-CA nanocomposite exhibited favorable antioxidant properties, biocompatibility, and the ability to promote cell migration in vitro. The role of PZ-CA nanocomposite in skin regeneration was explored by a mice model. Results in vivo suggest that the PZ-CA nanocomposite promotes wound healing with a faster rate as compared with a commercial spray solution, mostly through attenuating the oxidative stress, promoting cell proliferation and collagen deposition. This work not only provides a delivery vector for bioactive molecules, but also develops a kind of nanocomposite with the property of promoting wound healing.

PMN-incorporated multifunctional chitosan hydrogel for postoperative synergistic photothermal melanoma therapy and skin regeneration

Melanoma excision surgery is usually accompanied by neoplasm residual, tissue defect, and bacterial infection, resulting in high tumor recurrence and chronic wound. Nanocomposite hydrogels can satisfy the twin requirements of avoiding tumor recurrence and skin wound healing following skin melanoma surgery due to their photothermal anti-tumor and anti-bacterial activities. In this study, carboxymethyl chitosan, oxidized fucoidan and polyphenol-metal nanoparticle (PMN) of tannic acid capped gold nanoparticles were used to fabricate multifunctional nanocomposite hydrogels through Schiff base reaction. The prepared hydrogel demonstrated outstanding photothermal effect, and the controlled high temperature will rapidly kill melanoma cells as well as bacteria within 10 min. Good injectability, self-healing and adhesion combined with high reactive oxygen species (ROS) scavenging capacity, hemostasis and biocompatibility made this hydrogel platform perfect for the postoperative treatment of melanoma and promoting wound healing. With the assistance of NIR irradiance, hydrogel can inhibit tumor tissue proliferation and promote tumor cell apoptosis, thereby helping to prevent melanoma recurrence after surgical removal of tumors. Simultaneously, the irradiance heat and polyphenol component kill bacteria on the wound surface, eliminate ROS, inhibit inflammatory responses, and promote angiogenesis, collagen deposition, and skin regeneration, all of which help to speed up wound healing.

An ECM-mimicking assembled gelatin/hyaluronic acid hydrogel with antibacterial and radical scavenging functions for accelerating open wound healing

A multifunctional hydrogel dressing with hemostatic, antibacterial, and reactive oxygen species (ROS)-removing properties is highly desirable for the clinical treatment of open wounds. Although many wound dressings have been prepared, the modification of polymers is often involved in the preparation process, and the uncertainty of biological safety and stability of modified polymers hinders the clinical application of products. In this study, inspired by the composition and crosslinking pattern of extracellular matrix (ECM), a deeply ECM-mimicking multifunctional hydrogel dressing is created. Tannic acid (TA) and poly-ϵ-lysine (EPL) are added into a gelatin/hyaluronic acid (Gel/HA) matrix, and a stable hydrogel is formed due to the formation of the triple helix bundles of gelatin and hydrogen bonds between polymers. The introduction of TA and EPL endows the ECM-mimicking hydrogel with stable rheological properties, as well as antibacterial and hemostatic functions. The as-produced hydrogels have suitable swelling ratio, enzyme degradability, and good biocompatibility. In addition, it also shows a significant ability to eliminate ROS, which is confirmed by the elimination of 2,2-diphenyl-1-picrylhydrazyl free radical. Full-thickness skin wound repair experiment and histological analysis of the healing site in mice demonstrate that the developed ECM-mimicking Gel/HA hydrogels have a prominent effect on ECM formation and promotion of wound closure. Taken together, these findings suggest that the multifunctional hydrogels deeply mimicking the ECM are promising candidates for the clinical treatment of open wounds.

Bibliometric analysis of electrochemical disinfection: current status and development trend from 2002 to 2022

The removal of waterborne pathogens from water is critical in preventing the spread of waterborne diseases. Electrochemical methods have been extensively researched and implemented for disinfection, primarily owing to their simplicity, efficiency, and eco-friendliness. Thus, it is essential to conduct a review about the research progress and hotspots on this promising technique. In this paper, we provided a comprehensive bibliometric analysis to systematically study and analyze the current status, hotspots, and trends in electrochemical disinfection research from 2002 to 2022. This study analyzed literature related to electrochemical disinfection or electrochemical sterilization published in the Web of Science database from 2002 to 2022 using CiteSpace and Biblioshiny R language software packages. The analysis focused on the visualization and assessment of annual publication volume, discipline and journal distribution, collaborative networks, highly cited papers, and keywords to systematically understand the current status and trends of electrochemical disinfection. The results showed that between 2002 and 2022, 1171 publications related to electrochemical disinfection were published, with an exponential increase in the cumulative number of publications (y=17.518e0.2147x, R2= 0.9788). The publications covered 76 disciplines with many articles published in high-impact journals. However, the research power was characterized by a large number of scattered research efforts and insufficient cooperation, indicating the need for further innovative collaboration. The citation analysis and keyword analysis suggest that future development in this field may focus on optimizing electrode materials, investigating the disinfection performance of ·OH based systems, optimizing conditions for actual wastewater treatment, and reducing energy consumption to promote practical applications.

Recent advances in nanomaterial-mediated bacterial molecular action and their applications in wound therapy

Because of the multi-pathway antibacterial mechanisms of nanomaterials, they have received widespread attention in wound therapy. However, owing to the complexities of bacterial responses toward nanomaterials, antibacterial molecular mechanisms remain unclear, making it difficult to rationally design highly efficient antibacterial nanomaterials. Fortunately, molecular dynamics simulations and omics techniques have been used as effective methods to further investigate the action targets of nanomaterials. Therefore, the review comprehensively analyzes the antibacterial mechanisms of nanomaterials from the morphology-dependent antibacterial activity and physicochemical/optical properties-dependent antibacterial activity, which provided guidance for constructing excellently efficient and broad-spectrum antibacterial nanomaterials for wound therapy. More importantly, the main molecular action targets of nanomaterials from the membranes, DNA, energy metabolism pathways, oxidative stress defense systems, ribosomes, and biofilms are elaborated in detail. Furthermore, nanomaterials used in wound therapy are reviewed and discussed. Finally, future directions of nanomaterials from mechanisms to nanomedicine are further proposed.

A Homochiral Diphenylalanine Analog Based Mechanoresponsive Hydrogel: An Insight Towards Its Wound Healing Efficacy

Deciphering the most promising strategy for the evolution of potential wound-healing therapeutics is one of the greatest challenging affairs to date. The development of peptide-based smart scaffolds with innate antimicrobial, anti-inflammatory, and antioxidant properties is an appealing way out. Aligned to the goal a set of Hydrogelators I-IV were developed utilizing the concept of chiral orchestration in diphenylalanine fragment, such that the most potent construct with all the bench marks namely mechanoresponsiveness, biocompatibility, consistent antimicrobial and antioxidant properties, could be fished out from the design. Interestingly, our in vitro Antifungal and Lipid peroxidation analysis identified the homochiral isomer Boc-δ-Ava-L-Phe-L-Phe-OH (Hydrogelator I), as an ideal candidate for the wound healing experiment, so we proceeded for the in vivo histopathological and antioxidant measurements in Wister rats. Indeed the wound images obtained from the different sets of animals on the 14th day of treatment demonstrated that with increased recovery time, hydrogelator I displayed a significant reduction in the lesion diameter compared to the marketed drug, and negative control. Even the histopathological measurements using H & E staining demonstrated diminished tissue destruction, neutrophil infiltration necrosis, and lymphatic proliferation in the hydrogelators, in comparison to others, backed by in vivo lipid peroxidation data. Overall our investigation certifies hydrogelator I as an effective therapeutic for managing the wound healing complication.

Microenvironment-responsive Cu-phenolic networks coated nanofibrous dressing with timely macrophage phenotype transition for chronic MRSA infected wound healing

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a pressing clinical issue that impedes wound healing. Pro-inflammatory M1 macrophages is required to clear bacteria and recruit various cell types during the initial phase of wound healing, but timing of this process is crucial. Herein, a microenvironment-responsive nanofibrous dressing capable of timely macrophage phenotype transition in vivo is constructed by coating copper ions (Cu2+)-polydopamine (PDA) networks on poly (ε-caprolactone) fiber (PCL-fiber) membrane. During the initial post-implantation period, the nanofibrous dressing show pH-sensitive Cu2+ release in the acidic infection microenvironment. The release Cu2+ have a direct killing effect on MRSA, and promote the proinflammatory M1 phenotype of macrophages to enhance the antibacterial macrophage response. Later, PDA to become a reactive oxygen species (ROS) scavenger when in microenvironments with elevated ROS levels, which conferred the dressing with an immunomodulatory activity that convert M1 macrophages into M2 macrophages. In vivo examination in an MRSA infected full-thickness skin wounds of rat model demonstrates that this dressing significantly facilitated infection eradication and wound healing through modulating local inflammatory phenotype. Overall, this study offers a simple and effective approach for timely manipulation of inflammation progression to promote infected wound healing.

Adipose-Derived Mesenchymal Stem Cell-Derived Exosomes Biopotentiated Extracellular Matrix Hydrogels Accelerate Diabetic Wound Healing and Skin Regeneration

Wound healing is an urgent clinical challenge, particularly in the case of chronic wounds. Traditional approaches to wound healing have limited therapeutic efficacy due to lengthy healing times, risk of immune rejection, and susceptibility to infection. Recently, adipose-derived mesenchymal stem cell-derived exosomes (ADSC-exos) have emerged as a promising modality for tissue regeneration and wound repair. In this study, the development of a novel extracellular matrix hydrogel@exosomes (ECM@exo) is reported, which entails incorporation of ADSC-exos into an extracellular matrix hydrogel (ECM hydrogel). This solution forms a hydrogel at physiological temperature (≈37 °C) upon local injection into the wound site. ECM@exo enables sustained release of ADSC-exos from the ECM hydrogel, which maintains high local concentrations at the wound site. The ECM hydrogel displays good biocompatibility and biodegradability. The in vivo and in vitro results demonstrate that ECM@exo treatment effectively reduces inflammation and promotes angiogenesis, collagen deposition, cell proliferation, and migration, thereby accelerating the wound healing process. Overall, this innovative therapeutic approach offers a new avenue for wound healing via a biological hydrogel with controlled exosome release.

Carrier-Free Binary Self-Assembled Nanomedicines Originated from Traditional Herb Medicine with Multifunction to Accelerate MRSA-Infected Wound Healing by Antibacterial, Anti-Inflammation and Promoting Angiogenesis

Background

Deaths from bacterial infections have risen year by year. This trend is further aggravated as the overuse antibiotics and the bacterial resistance to all known antibacterial agents. Therefore, new therapeutic alternatives are urgently needed.

Methods

Enlightenment the combination usage of traditional herb medicine, one carrier-free binary nanoparticles (GA-BBR NPs) was discovered, which was self-assembled from gallic acid and berberine through electrostatic interaction, π-π stacking and hydrophobic interaction; and it could be successfully prepared by a green, cost-effective and "one-pot" preparation process.

Results

The nanoparticles exhibited strong antibacterial activity and biofilm removal ability against multidrug-resistant S. aureus (MRSA) by downregulating mRNA expression of rpsF, rplC, rplN, rplX, rpsC, rpmC and rpsH to block bacterial translation mechanisms in vitro and in vivo, and it had well anti-inflammatory activity and a promising role in promoting angiogenesis to accelerate the wound healing on MRSA-infected wounds model in vivo. Additionally, the nanoparticles displayed well biocompatibility without cytotoxicity, hemolytic activity, and tissue or organ toxicity.

Conclusion

GA-BBR NPs originated from the drug combination has potential clinical transformation value, and this study provides a new idea for the design of carrier-free nanomedicine derived from natural herbals.

Microenvironment responsive nanocomposite hydrogel with NIR photothermal therapy, vascularization and anti-inflammation for diabetic infected wound healing

Bacterial infection, excessive inflammation and damaging blood vessels network are the major factors to delay the healing of diabetic ulcer. At present, most of wound repair materials are passive and can't response to the wound microenvironment, resulting in a low utilization of bioactive substances and hence a poor therapeutic effect. Therefore, it's essential to design an intelligent wound dressing responsive to the wound microenvironment to achieve the release of drugs on-demand on the basis of multifunctionality. In this work, metformin-laden CuPDA NPs composite hydrogel (Met@ CuPDA NPs/HG) was fabricated by dynamic phenylborate bonding of gelatin modified by dopamine (Gel-DA), Cu-loaded polydopamine nanoparticles (CuPDA NPs) with hyaluronic acid modified by phenyl boronate acid (HA-PBA), which possessed good injectability, self-healing, adhesive and DPPH scavenging performance. The slow release of metformin was achieved by the interaction with CuPDA NPs, boric groups (B-N coordination) and the constraint of hydrogel network. Metformin had a pH and glucose responsive release behavior to treat different wound microenvironment intelligently. Moreover, CuPDA NPs endowed the hydrogel excellent photothermal responsiveness to kill bacteria of >95% within 10 min and also the slow release of Cu²⁺ to protect wound from infection for a long time. Met@ CuPDA NPs/HG also recruited cells to a certain direction and promoted vascularization by releasing Cu²⁺. More importantly, Met@CuPDA NPs/HG effectively decreased the inflammation by eliminating ROS and inhibiting the activation of NF-κB pathway. Animal experiments demonstrated that Met@CuPDA NPs/HG significantly promoted wound healing of diabetic SD rats by killing bacteria, inhibiting inflammation, improving angiogenesis and accelerating the deposition of ECM and collagen. Therefore, Met@CuPDA NPs/HG had a great application potential for diabetic wound healing.

Tannic acid-based dual-network homogeneous hydrogel with antimicrobial and pro-healing properties for infected wound healing

The clinical treatment of infected skin injuries caused by exogenous bacteria faces great challenges. Conventional therapeutic approaches are difficult to achieve synergistic effects of infection control and induction of skin regeneration. In this study, a novel tannic acid-based physically cross-linked double network hydrogel (PDH gel) was prepared on demand by covalent cross-linking of tannic acid (TA) with polyvinyl alcohol (PVA) and chelating ligand of TA with Fe³⁺. The homogeneity of the hydrogel was achieved by the action of glycol dispersant. With the anti-inflammatory and antioxidant properties of Fe³⁺ and TA, this hydrogel exhibited excellent antibacterial properties by achieving 99.69% and 99.36% bacterial inhibition against E.coli and S. aureus, respectively. Moreover, the PDH gel exhibits good biocompatibility, stretchability (up to 200%) and skin-friendliness. After 14 days of PDH-1 gel implantation in a rat model infected by S. aureus, the wound healing rate was as high as 95.21%. PDH gel-1 showed more granulation tissue, more pronounced blood vessels, higher collagen fiber density and good collagen deposition, and its recovery effect was better than that of PSH gel and PDH gel-2 in vivo. Hence, this study provides a novel avenue for the design of future clinical infected wound healing dressings.

Amphiphilic Nano-Swords for Direct Penetration and Eradication of Pathogenic Bacterial Biofilms

Bacterial biofilms are major causes of persistent and recurrent infections and implant failures. Biofilms are formable by most clinically important pathogens worldwide, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, causing recalcitrance to standard antibiotic therapy or anti-biofilm strategies due to amphiphilic impermeable extracellular polymeric substances (EPS) and the presence of resistant and persistent bacteria within the biofilm matrix. Herein, we report our design of an oligoamidine-based amphiphilic "nano-sword" with high structural compacity and rigidity. Its rigid, amphiphilic structure ensures effective penetration into EPS, and the membrane-DNA dual-targeting mechanism exerts strong bactericidal effect on the dormant bacterial persisters within biofilms. The potency of this oligoamidine is shown in two distinct modes of application: it may be used as a coating agent for polycaprolactone to fully inhibit surface biofilm growth in an implant-site mimicking micro-environment; meanwhile, it cures model mice of biofilm infections in various ex vivo and in vivo studies.

Inflammation-modulating antibacterial hydrogel sustained release asiaticoside for infection wound healing

Wound infection and persistent inflammation are considered to be the main reasons for hindering wound healing. In this study, we developed an innovative hydrogel dressing, EPL-DA/ODEX/AMs, as a platform to inhibit bacteria and inflammation and promote wound healing. Polylysine (EPL) has cationic properties and can effectively disrupt bacterial cell membranes for antibacterial purposes. Polylysine-grafted levodopa (EPL-DA) with abundant amino and catechol groups can be cross-linked with oxidized dextran through Schiff base reaction to form antibacterial hydrogels with good adhesion and mechanical properties. In addition, asiaticoside, which can effectively inhibit inflammation and promote collagen regeneration, is made into PLGA microspheres to effectively deliver asiaticoside to the wound. The innovative antibacterial hydrogel of EPL-DA/ODEX/AMs may become a competitive wound dressing for infected wound.

Biological Activities and Biocompatibility Properties of Eu(OH)3 and Tb(OH)3 Nanorods: Evaluation for Wound Healing Applications

Rare earth elements have shown promising results in both bio-imaging and therapy applications due to their superior magnetic, catalytic, and optical properties. In recent years, since lanthanide-based nanomaterials have effective results in wound healing, it has become necessary to investigate the different properties of these nanoparticles. The aim of this study is to investigate the antimicrobial, antibiofilm, and biocompability of Eu(OH)₃ and Tb(OH)₃ nanorods, which have a high potential by triggering angiogenesis and providing ROS activity, especially in wound healing. For this purpose, nanorods were obtained by the microwave-assisted synthesis method. Structural characterizations of Eu(OH)₃ and Tb(OH)₃ nanorods were performed by FT-IR, XRD, and TG-DTA methods, and morphological characterizations were performed by SEM-EDX. Microorganisms that are likely to be present in the wound environment were selected for the antimicrobial activities of the nanorods. The highest efficiency of nanorods with the disc diffusion method was shown against Pseudomonas aeruginosa ATCC 27,853 and Candida albicans ATCC 10,231 microorganisms. One of the problems frequently encountered in an infected wound environment is the formation of bacterial biofilm. Eu(OH)₃ nanorods inhibited 77.5 ± 0.43% and Tb(OH)₃ nanorods 76.16 ± 0.60% of Pseudomonas aeruginosa ATCC 27,853 biofilms. These results show promise for the development of biomaterials with superior properties by adding these nanorods to wound dressings that will be developed especially for wounds with microbial infection. Eu(OH)₃ nanorods are more toxic than Tb(OH)₃ nanorods on NCTC L929 cells. At concentrations of 500 µg/ml and above, both nanorods are toxic to cells.

Metal-coordination synthesis of a natural injectable photoactive hydrogel with antibacterial and blood-aggregating functions for cancer thermotherapy and mild-heating wound repair

Photothermal therapy (PTT) is a promising approach for treating cancer. However, it suffers from the formation of local lesions and subsequent bacterial infection in the damaged area. To overcome these challenges, the strategy of mild PTT following the high-temperature ablation of tumors is studied to achieve combined tumor suppression, wound healing, and bacterial eradication using a hydrogel. Herein, Bi₂S₃ nanorods (NRs) are employed as a photothermal agent and coated with hyaluronic acid to obtain BiH NRs with high colloidal stability. These NRs and allantoin are loaded into an injectable Fe³⁺-coordinated hydrogel composed of sodium alginate (Alg) and Farsi gum (FG), which is extracted from Amygdalus scoparia Spach. The hydrogel can be used for localized cancer therapy by high-temperature PTT, followed by wound repair through the combination of mild hyperthermia and allantoin-mediated induction of cell proliferation. In addition, an outstanding blood clotting effect is observed due to the water-absorbing ability and negative charge of FG and Alg as well as the porous structure of hydrogels. The hydrogels also eradicate infection owing to the local heat generation and intrinsic antimicrobial activity of the NRs. Lastly, in vivo studies reveal an efficient photothermal-based tumor eradication and accelerated wound healing by the hydrogel.

Succinic Ester-Based Shape Memory Gelatin Sponge for Noncompressible Hemorrhage without Hindering Tissue Regeneration

Shape memory sponges are very promising in stopping the bleeding from noncompressible and narrow entrance wounds. However, few shape memory sponges have fast degradable properties in order to not hinder tissue healing. In this work, based on cryopolymerization, a succinic ester-based sponge (Ssponge) is fabricated using gelatin and bi-polyethylene glycol-succinimidyl succinate (Bi-PEG-SS). Compared with the commercially available gelatin sponge (Csponge), Ssponge possesses better water/blood absorption ability and higher mechanical pressure over the surrounding tissues. Moreover, in the models of massive liver hemorrhage after transection and noncompressive liver wounds by penetration, Ssponge exhibits a better hemostasis performance than Csponge. Furthermore, in a liver regeneration model, Ssponge-treated livers shows higher regeneration speed compared with Csponge, including a lower injury score, more cavity-like tissues, less fibrosis and enhanced tissue regeneration. Overall, it is shown that Ssponge, with a fast degradation behavior, is not only highly efficient in stopping bleeding but also not detrimental for tissue healing, possessing promising clinical translational potential.

Engineering multifunctional bioactive citrate-based biomaterials for tissue engineering

Developing bioactive biomaterials with highly controlled functions is crucial to enhancing their applications in regenerative medicine. Citrate-based polymers are the few bioactive polymer biomaterials used in biomedicine because of their facile synthesis, controllable structure, biocompatibility, biomimetic viscoelastic mechanical behavior, and functional groups available for modification. In recent years, various multifunctional designs and biomedical applications, including cardiovascular, orthopedic, muscle tissue, skin tissue, nerve and spinal cord, bioimaging, and drug or gene delivery based on citrate-based polymers, have been extensively studied, and many of them have good clinical application potential. In this review, we summarize recent progress in the multifunctional design and biomedical applications of citrate-based polymers. We also discuss the further development of multifunctional citrate-based polymers with tailored properties to meet the requirements of various biomedical applications.

•

Multifunctional bioactive citrate-based biomaterials have broad applications in regenerative medicine.

•

Recent advances in multifunctional design and biomedical applications of citate-based polymers are summarized.

•

Future challenge of citrate-based polymers in various biomedical applications are discussed.

Milk Exosomes Facilitate Oral Delivery of Drugs against Intestinal Bacterial Infections

Biopharmaceutics Classification System (BCS) class II and IV drugs exhibit low solubility and suffer a limitation in oral administration. Exosomes have attracted intensive attention in the efficient delivery of such compounds. However, low gastrointestinal stability and high production cost of exosomes hinder their development as drug carriers. Here, milk exosomes are functionalized with phosphatidylserine and are capable of improving the solubility of BCS class II and IV drugs, resulting in facilitating the oral delivery of the drugs. A natural flavonoid, α-mangostin, is loaded into exosomes (AExo) to enhance the antibacterial efficiency, demonstrated by clearing 99% of bacteria in macrophages. Furthermore, AExo exhibits high mucus penetrability and shows a significant therapeutic efficacy in two animal infection models. Collectively, this work expands the application of exosomes from bovine milk with simple operation and low cost, shedding light on the potential of milk exosomes in improving the solubility of drugs to enhance the efficacy of oral administration.

Current Progress and Outlook of Nano-Based Hydrogel Dressings for Wound Healing

Wound dressing is an important tool for wound management. Designing wound dressings by combining various novel materials and drugs to optimize the peri-wound environment and promote wound healing is a novel concept. Hydrogels feature good ductility, high water content, and favorable oxygen transport, which makes them become some of the most promising materials for wound dressings. In addition, nanomaterials exhibit superior biodegradability, biocompatibility, and colloidal stability in wound healing and can play a role in promoting healing through their nanoscale properties or as carriers of other drugs. By combining the advantages of both technologies, several outstanding and efficient wound dressings have been developed. In this paper, we classify nano-based hydrogel dressings into four categories: hydrogel dressings loaded with a nanoantibacterial drug; hydrogel dressings loaded with oxygen-delivering nanomedicines; hydrogel dressings loaded with nanonucleic acid drugs; and hydrogel dressings loaded with other nanodelivered drugs. The design ideas, advantages, and challenges of these nano-based hydrogel wound dressings are reviewed and analyzed. Finally, we envisaged possible future directions for wound dressings in the context of relevant scientific and technological advances, which we hope will inform further research in wound management.

Engineering functional natural polymer-based nanocomposite hydrogels for wound healing

Skin injury occurs due to acute trauma, chronic trauma, infection, and surgical intervention, which can result in severe dysfunction and even death in humans. Therefore, clinical intervention is critical for the treatment of skin wounds. One idealized method is to use wound dressings to protect skin wounds and promote wound healing. Among these wound dressings, nanocomposite natural polymer hydrogels (NNPHs) are multifunctional wound dressings for wound healing. The combination of nanomaterials and natural polymer hydrogels avoids the shortcomings of a single component. Moreover, nanomaterials could provide improved antibacterial, anti-inflammatory, antioxidant, stimuli-responsive, electrically conductive and mechanical properties of hydrogels to accelerate wound healing. This review focuses on recent advancements in NNPHs for skin wound healing and repair. Initially, the functions and requirements of NNPHs as wound dressings were introduced. Second, the design, preparation and capacities of representative NNPHs are classified based on their nanomaterial. Third, skin wound repair applications of NNPHs have been summarized based on the types of wounds. Finally, the potential issues of NNPHs are discussed, and future research is proposed to prepare idealized multifunctional NNPHs for skin tissue regeneration.

Design of Near-Infrared-Triggered Cellulose Nanocrystal-Based In Situ Intelligent Wound Dressings for Drug-Resistant Bacteria-Infected Wound Healing

Postoperative infected wound complications caused by residual tumor cells, bacterial biofilms, and drug-resistant bacteria have become the main challenge in postsurgical skin regeneration. Herein, a bionic cellulose nanocrystal (CNC)-based in situ intelligent wound dressing with near-infrared (NIR)-, temperature-, and pH-responsive functions was designed by using NIR-responsive CNC as the network skeleton, dynamic imine bonds between dialdehyde cellulose nanocrystals and doxorubicin, chitosan oligosaccharide as the pH-responsive switch, and temperature-sensitive poly(N-isopropyl acrylamide) as the temperature-responsive in situ formation switch. The as-prepared wound dressing with the intertwining three-dimensional (3D) network structure possessed high drug loadability of indocyanine green (30 mg/g) and doxorubicin (420 mg/g) simultaneously. The temperature-, NIR-, and pH-responsive switches endowed the wound dressing with controllable on-demand drug release behavior. In particular, the temperature switch endowed the dressing with a shape-adaptable ability on irregularly infected wounds. Interestingly, the wound dressing showed excellent antitumor activity for A375 tumor cells, antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and bacterial biofilm removal ability. Therefore, the developed wound dressing can provide an ideal synergistic treatment strategy combined with chemotherapy and photodynamic and photothermal therapy for postoperative drug-resistant bacteria-infected wound healing.

Dual-Functional Nanofibrous Patches for Accelerating Wound Healing

Bacterial infections and inflammation are two main factors for delayed wound healing. Coaxial electrospinning nanofibrous patches, by co-loading and sequential co-delivering of anti-bacterial and anti-inflammation agents, are promising wound dressing for accelerating wound healing. Herein, curcumin (Cur) was loaded into the polycaprolactone (PCL) core, and broad-spectrum antibacterial tetracycline hydrochloride (TH) was loaded into gelatin (GEL) shell to prepare PCL-Cur/GEL-TH core-shell nanofiber membranes. The fibers showed a clear co-axial structure and good water absorption capacity, hydrophilicity and mechanical properties. In vitro drug release results showed sequential release of Cur and TH, in which the coaxial mat showed good antioxidant activity by DPPH test and excellent antibacterial activity was demonstrated by a disk diffusion method. The coaxial mats showed superior biocompatibility toward human immortalized keratinocytes. This study indicates a coaxial nanofiber membrane combining anti-bacterial and anti-inflammation agents has great potential as a wound dressing for promoting wound repair.

Enzyme-Responsive COF-Based Thiol-Targeting Nanoinhibitor for Curing Bacterial Infections

Pathogen infections impose severe challenges in clinical practice, especially for patients infected with antibiotic-resistant microbes. The thioredoxin (Trx) system in Gram-positive bacteria serves as an ideal antimicrobial target for novel medicine design due to the structural differences from corresponding system in mammals. However, a backup thiol-dependent antioxidant glutathione (GSH) system limits the effectiveness of drugs in many Gram-negative bacteria. Herein, we synthesize a thiol-targeting nanoinhibitor based on an enzyme-responsive covalent organic framework (COF) coloaded with silver nanoparticles (AgNPs) and ebselen (EBS) (Ag-TA-CON@EBS@PEG) to exert synergistic antibacterial effects. Since azoreductase can dissociate the enzyme-responsive COF, we adopt this strategy to achieve the accurate release of EBS and Ag⁺ at infection sites. Our research identifies that the functionalized nanoinhibitor shows excellent bactericidal performance for Gram-positive and Gram-negative bacteria in vitro and exhibits low toxicity to normal cells. Besides, the nanoinhibitor presents favorable biocompatibility, anti-inflammatory property, and effective wound healing ability in mice. This paper provides a promising clinical strategy for synergistic antibacterial therapy and enhanced wound healing properties via an optimized combination of the targeted nanomedicines with an intelligent drug conveying platform.

Rational Design of Intelligent and Multifunctional Dressing to Promote Acute/Chronic Wound Healing

Currently, the clinic's treatment of acute/chronic wounds is still unsatisfactory due to the lack of functional and appropriate wound dressings. Intelligent and multifunctional dressings are considered the most advanced wound treatment modalities. It is essential to design and develop wound dressings with required functions according to the wound microenvironment in the clinical treatment. This work summarizes microenvironment characteristics of various common wounds, such as acute wound, diabetic wound, burns wound, scalded wound, mucosal wound, and ulcers wound. Furthermore, the factors of transformation from acute wounds to chronic wounds were analyzed. Then we focused on summarizing how researchers fully and thoroughly combined the complex microenvironment with modern advanced technology to ensure the usability and value of the dressing, such as photothermal-sensitive dressings, microenvironment dressing (pH-sensitive dressings, ROS-sensitive dressings, and osmotic pressure dressings), hemostatic dressing, guiding tissue regeneration dressing, microneedle dressings, and 3D/4D printing dressings. Finally, the revolutionary development of wound dressings and how to transform the existing advanced functional dressings into clinical needs as soon as possible have carried out a reasonable and meaningful outlook.

Regenerative antibacterial hydrogels from medicinal molecule for diabetic wound repair

Hydrogel products for chronic diabetic wounds, a serious and prevalent complication of diabetes, show limited effects on disability and remain nonspecific. Thus, improvements in the usage of pharmaceutical molecule in the hydrogels are highly desirable to increase the therapeutic effect of hydrogels. In this study, thioctic acid (a common medicine molecule in diabetes treatment) is used for preparing regenerative antibacterial hydrogels (RAH) which contains in situ synthesized silver nanoparticles (AgNPs). The RAH shows regenerative, self-healing and injectable ability, because of the reversible hydrogen and coordination bonds. With good regenerative capacity, RAH can be stored as powder to avoid the water loss and facilitate storage availability. Owing to the antioxidant properties of thioctic acid, the RAH can decrease the oxidative damage and retain cell proliferation efficiency. Due to the in situ synthesized AgNPs, the RAH also exhibits extraordinary antimicrobial capacities against MDR bacteria. All of these superiorities enable RAH to be a promising therapy for chronic diabetic wounds.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

In Situ Transformation of Electrospun Nanofibers into Nanofiber-Reinforced Hydrogels

Nanofiber-reinforced hydrogels have recently gained attention in biomedical engineering. Such three-dimensional scaffolds show the mechanical strength and toughness of fibers while benefiting from the cooling and absorbing properties of hydrogels as well as a large pore size, potentially aiding cell migration. While many of such systems are prepared by complicated processes where fibers are produced separately to later be embedded in a hydrogel, we here provide proof of concept for a one-step solution. In more detail, we produced core-shell nanofibers from the natural proteins zein and gelatin by coaxial electrospinning. Upon hydration, the nanofibers were capable of directly transforming into a nanofiber-reinforced hydrogel, where the nanofibrous structure was retained by the zein core, while the gelatin-based shell turned into a hydrogel matrix. Our nanofiber-hydrogel composite showed swelling to ~800% of its original volume and water uptake of up to ~2500% in weight. The physical integrity of the nanofiber-reinforced hydrogel was found to be significantly improved in comparison to a hydrogel system without nanofibers. Additionally, tetracycline hydrochloride was incorporated into the fibers as an antimicrobial agent, and antimicrobial activity against Staphylococcus aureus and Escherichia coli was confirmed.

Co-spray-dried poly-L-lysine with L-leucine as dry powder inhalations for the treatment of pulmonary infection: Moisture-resistance and desirable aerosolization performance

Poly-L-lysine (PLL) is a promising candidate for the treatment of pulmonary infection with lower occurrence of drug-resistance due to its unique antibacterial mechanisms. Dry powder inhalations (DPIs) are considered as the first choice for formulating PLL to treat pulmonary infection on account of direct delivery and satisfactory stability. However, hygroscopicity of PLL limited its therapeutic effect on pulmonary infection when PLL developed into DPIs. The hygroscopicity caused two obstacles including the low drug deposition in the lower respiratory tract and undesirable aerosolization performance deterioration. In this study, PLL was co-spray-dried with L-leucine (LL) to achieve moisture-resistance and desirable aerosolization performance. The ratio of PLL and LL was optimized to obtain particles with different morphology, hygroscopicity and aerodynamic properties. The obtained PLL DPIs were suitable for inhalation with a corrugated surface formed by hydrophobic LL. The anti-hygroscopicity, aerosolization performance and rheological properties of P₂ DPIs were optimal when PLL:LL = 85:15. The DPIs particles were stable after being stored at high relative humidity (60 ± 5%), and their superiority in treating pulmonary infections was also proved by in vitro and in vivo experiments. The established PLL DPIs were proved to be a feasible and desirable approach to treat pulmonary infections.

Exosomes from human adipose-derived mesenchymal stromal/stem cells accelerate angiogenesis in wound healing: implication of the EGR-1/lncRNA-SENCR/DKC1/VEGF-A axis

Exosomes (Exos) extracted from human adipose mesenchymal stromal/stem cells (hAD-MSCs) have been reported as therapeutic tools for tissue repair, but how they regulate angiogenesis of endothelial cells remains unknown. In this study, hAD-MSCs were isolated, and early growth response factor-1, Smooth muscle and endothelial cell enriched migration/differentiation-associated long-noncoding RNA (lncRNA-SENCR), and vascular endothelial growth factor-A (VEGF-A) overexpression or knockdown was achieved. Exos extracted from hAD-MSCs (hADSC-Exos) were co-cultured with human umbilical vein endothelial cells (HUVECs) to detect the effects of EGR-1, lncRNA-SENCR, and VEGF-A on angiogenesis and the relationships between EGR-1, lncRNA-SENCR, Dyskerin pseudouridine synthase 1 (DKC1), and VEGF-A. An in vivo experiment verified the effect of hADSC-Exos on the wound healing process. hADSC-Exos substantially promoted the proliferation, migration, and angiogenesis of HUVECs, which could be reversed by short-hairpin RNA SENCR (shSENCR) transfection. hADSC-Exos had elevated expression of EGR-1, which bound to the lncRNA-SENCR promoter. The suppressive effect of Exo-shEGR1 on HUVECs was counteracted by SENCR overexpression. LncRNA-SENCR was shown to interact with DKC1. Overexpression of DKC1 or lncRNA-SENCR maintained stable VEGF-A expression. Overexpression of VEGF-A reversed the suppressive effect of shSENCR on HUVECs. Consistent results were obtained in mice in vivo. Overall, hADSC-Exo EGR-1 upregulates lncRNA-SENCR expression to activate the DKC1/VEGF-A axis, facilitating the wound-healing process by increasing angiogenesis.

An overview on electrospinning and its advancement toward hard and soft tissue engineering applications

One of the emerging technologies of the recent times harboring nanotechnology to fabricate nanofibers for various biomedical and environmental applications are electrospinning (nanofiber technology). Their relative ease in use, simplicity, functionality and diversity has surpassed the pitfalls encountered with the conventional method of generating fibers. This review aims to provide an overview of electrospinning, principle, methods, feed materials, and applications toward tissue engineering. To begin with, evolution of electrospinning and its typical apparatus have been briefed. Simultaneously, discussion on the production of nanofibers with diversified feed materials such as polymers, small molecules, colloids, and nanoparticles and its transformation into a powerful technology has been dealt with. Further, highlights on the application of nanofibers in tissue engineering and the commercialized products developed using nanofiber technology have been summed up. With this rapidly emerging technology, there would be a great demand pertaining to scalability and environmental challenge toward tissue engineering applications.

Enhanced postoperative cancer therapy by iron-based hydrogels

Surgical resection is a widely used method for the treatment of solid tumor cancers. However, the inhibition of tumor recurrence and metastasis are the main challenges of postoperative tumor therapy. Traditional intravenous or oral administration have poor chemotherapeutics bioavailability and undesirable systemic toxicity. Polymeric hydrogels with a three-dimensional network structure enable on-site delivery and controlled release of therapeutic drugs with reduced systemic toxicity and have been widely developed for postoperative adjuvant tumor therapy. Among them, because of the simple synthesis, good biocompatibility, biodegradability, injectability, and multifunctionality, iron-based hydrogels have received extensive attention. This review has summarized the general synthesis methods and construction principles of iron-based hydrogels, highlighted the latest progress of iron-based hydrogels in postoperative tumor therapy, including chemotherapy, photothermal therapy, photodynamic therapy, chemo-dynamic therapy, and magnetothermal-chemical combined therapy, etc. In addition, the challenges towards clinical application of iron-based hydrogels have also been discussed. This review is expected to show researchers broad perspectives of novel postoperative tumor therapy strategy and provide new ideas in the design and application of novel iron-based hydrogels to advance this sub field in cancer nanomedicine.

Design and Fabrication of a Dual Protein-Based Trilayered Nanofibrous Scaffold for Efficient Wound Healing

Chronic wound healing is a major threat all over the world. There are currently a plethora of biomaterials-based wound dressings available for wound healing applications. In this study, a dual protein-based (silk fibroin and sericin) nanofibrous scaffold from a natural source (B.mori silkworm cocoons) with antibacterial and antioxidative properties for wound healing was investigated. An electrospun layer-by-layer silk protein-based nanofibrous scaffold was fabricated with a top layer of hydrophobic silk fibroin protein blended with polyvinyl alcohol (PVA), a middle layer of waste protein silk sericin loaded with silver(I) sulfadiazine as an antibacterial agent, and a bottom layer using silk fibroin blended with polycaprolactone (PCL). The trilayered nanofibrous scaffold with a smooth and bead-free morphology demonstrated excellent wettability, slow in vitro degradation, controlled drug release, and potent antibacterial and antioxidant properties. In vitro, the scaffold also demonstrated excellent hemocompatibility and biocompatibility. Furthermore, in vivo wound contraction, histological, and micro-CT investigations show complete wound healing and the formation of new skin tissue in a male Balb/c mouse model treated with the scaffold. The antioxidant properties of the sericin protein and SSD-based triple-layered nanofibrous scaffold protect the wound from bacterial infection and improve wound healing in a mouse model. The current study develops a dual protein-based nanofibrous scaffold with antibacterial and antioxidant properties as a promising wound dressing material.

A review of current advancements for wound healing: Biomaterial applications and medical devices

Wound healing is a complex process that is critical in restoring the skin's barrier function. This process can be interrupted by numerous diseases resulting in chronic wounds that represent a major medical burden. Such wounds fail to follow the stages of healing and are often complicated by a pro‐inflammatory milieu attributed to increased proteinases, hypoxia, and bacterial accumulation. The comprehensive treatment of chronic wounds is still regarded as a significant unmet medical need due to the complex symptoms caused by the metabolic disorder of the wound microenvironment. As a result, several advanced medical devices, such as wound dressings, wearable wound monitors, negative pressure wound therapy devices, and surgical sutures, have been developed to correct the chronic wound environment and achieve skin tissue regeneration. Most medical devices encompass a wide range of products containing natural (e.g., chitosan, keratin, casein, collagen, hyaluronic acid, alginate, and silk fibroin) and synthetic (e.g., polyvinyl alcohol, polyethylene glycol, poly[lactic‐co‐glycolic acid], polycaprolactone, polylactic acid) polymers, as well as bioactive molecules (e.g., chemical drugs, silver, growth factors, stem cells, and plant compounds). This review addresses these medical devices with a focus on biomaterials and applications, aiming to deliver a critical theoretical reference for further research on chronic wound healing.

Alloyed nanostructures integrated metal-phenolic nanoplatform for synergistic wound disinfection and revascularization

New materials for combating bacteria-caused infection and promoting the formation of microvascular networks during wound healing are of vital importance. Although antibiotics can be used to prevent infection, treatments that can disinfect and accelerate wound healing are scarce. Herein, we engineer a coating that is both highly compatible with current wound dressing substrates and capable of simultaneously disinfecting and revascularizing wounds using a metal-phenolic nanoplatform containing an alloyed nanostructured architecture (Ag@Cu-MPN_NC). The alloyed nanostructure is formed by the spontaneous co-reduction and catalytic disproportionation reaction of multiple metal ions on a foundation metal-phenolic supramolecular layer. This synergistic presence of metals greatly improves the antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria, while demonstrating negligible cytotoxicity to normal tissue. In infected rat models, the Ag@Cu-MPN_NC could kill bacteria efficiently, promoting revascularization and accelerate wound closure with no adverse side effects in infected in vivo models. In other words, this material acts as a combination therapy by inhibiting bacterial invasion and modulating bio-nano interactions in the wound.

Multi-activity cobalt ferrite/MXene nanoenzymes for drug-free phototherapy in bacterial infection treatment

Drug-free antibacterial strategies are of great significance for pathogenic bacterial infection treatment in clinical practice. Phototherapy with antibacterial function plays a vital role in mainstream germicidal research. However, phototherapy could lead to residual heat and excess reactive oxygen species (ROS), which are the main side-effects during antibacterial treatment. Unique CoFe₂O₄/MXene (CM) nanoenzymes, which were fabricated with electrostatic interactions, have been designed to conquer those challenges caused by side-effects of phototherapy in our research. The CM nanoenzymes possess many promising properties including photothermal and photodynamic induced phototherapy and mimic peroxidase (POD), glutathione oxidase (GSHOx), and catalase (CAT). Upon treatment with near-infrared (NIR) light, CM nanoenzymes can create a local high-temperature circumstance as well as raise bacterial membrane permeability. Furthermore, the photodynamic process and multi-enzyme-mimicking activities of CM enzymes boost the interbacterial ROS level. Herein, bacteria can hardly survive in synergistic phototherapy and multi-enzyme-mimicking catalytic therapy in vitro and in vivo. Meanwhile, the CM nanoenzymes exhibit excellent biocompatibility in vitro and in vivo. Overall, this research establishes a strong foundation for effectively employing nanoenzymes, leading to a new way to cure bacterial infections.

The CM nanoenzymes are synthesized with electrostatic interactions. Bacteria can hardly survive synergistic phototherapy and multi-enzyme-mimicking catalytic therapy with CM, which reinforces the foundation of drug-free antibacterial strategies.