Hierarchically multifunctional bioactive nanoglass for integrated tumor/infection therapy and impaired wound repair

Global Advancements in Bioactive Material Manufacturing for Drug Delivery: A Comprehensive Study

Manufacturing bioactive materials for drug delivery involves developing materials that interact with biological tissues to release drugs in a controlled and targeted manner. The goal is to optimize therapeutic efficacy and reduce side effects by combining knowledge from materials engineering, biology, and pharmacology. This study presents a detailed bibliometric analysis, exploring the keywords "manufacturing," "bioactive materials," and "drug delivery" to identify and highlight significant advancements in the field. From the Web of Science, 36,504 articles were analyzed, with 171 selected for a deeper analysis, identifying key journals, countries, institutions, and authors. The results highlight the field's interdisciplinary nature, with keywords grouped into four main themes, including regenerative medicine, scaffolds, three-dimensional (3D) printing, bioactive glass, and tissue engineering. Future research in this area will focus on more effective and precise systems using technologies like 3D printing and nanotechnology to enhance the customization and control of drug release, aiming for more efficient and targeted therapies.

Photo-controlled multifunctional hydrogel for photothermal sterilization and microenvironment amelioration of infected diabetic wounds

Diabetic foot ulcers are linked to a high disability rate, with no effective treatment currently available. Addressing infection, reducing oxidative stress, and safely managing chronic inflammation remain major challenges. In this study, a composite hydrogel dressing was developed using natural substances or clinically approved components (dopamine, D-alpha-tocopheryl polyethylene glycol succinate, and rhein). Upon near-infrared laser irradiation, the composite system rapidly heats and solidifies into a gel with photothermal antibacterial properties. Additionally, the decomposition of hydrogen peroxide releases oxygen, alleviating wound hypoxia. The hydrogel exhibited strong bactericidal activity against multiple bacterial strains. Without laser irradiation, the hydrogel effectively scavenged various free radicals and intracellular reactive oxygen species, restoring redox balance. Furthermore, it significantly reduced the expression of inflammatory cytokines, including interleukin-6 and interleukin-1β. In a diabetic mouse wound model infected with S. aureus, the mild photothermal therapy, combined with the antibacterial action of rhein, effectively managed bacterial infections, reduced inflammation, and promoted wound healing. Consequently, the photo-controlled therapeutic approach, offering antibacterial, antioxidant, and anti-inflammatory effects, holds promise for the effective treatment and management of infected diabetic wounds.

A bioactive multifunctional dressing with simultaneous visible monitoring of pH values and H2O2 concentrations for promoting diabetic wound healing

Wound healing in diabetes is a complex physiological process with risks of ulceration and amputation. Real-time monitoring and treatment of diabetic wounds is an effective prevention of further deterioration. Herein, a multifunctional dressing is developed by encapsulating europium-containing bioactive glass (EuBG) and MoO3-x in a biocompatible sodium alginate (SA) dressing (MoO3-x-EuBG-SA), aiming to simultaneously monitor the wound pH value and hydrogen peroxide (H2O2) concentration, establish an anti-inflammatory microenvironment, and promote wound healing. The pH-responsive fluorescence quenching effect of EuBG contributes to visible monitoring of pH values, and MoO3-x enables high responsiveness and accurate colorimetric indication of H2O2 variability to understand the dynamic wound status. Then, these fluorescent and colorimetric changes can be captured using a smartphone and transformed into signals for wound pH values and H2O2 concentrations, enabling rapid and convenient real-time assessment of wound dynamics. Furthermore, the MoO3-x-EuBG-SA dressing can reduce inflammation and promote the proliferation, differentiation, and migration of fibroblasts and endothelial cells in vitro with the help of the released bioactive Si, Ca, and Mo ions. Notably, the MoO3-x-EuBG-SA dressing exhibits excellent abilities to monitor a wound microenvironment and immune regulation and promote diabetic wound healing in vivo. Overall, the multifunctional dressing has great potential for managing diabetic wounds and promoting wound healing.

Advanced Thermoactive Nanomaterials for Thermomedical Tissue Regeneration: Opportunities and Challenges

Nanomaterials usually possess remarkable properties, including excellent biocompatibility, unique physical and chemical characteristics, and bionic attributes, which make them highly promising for applications in tissue regeneration. Thermal therapy has emerged as a versatile approach for wound healing, nerve repair, bone regeneration, tumor therapy, and antibacterial tissue regeneration. By combining nanomaterials with thermal therapy, multifunctional nanomaterials with thermogenic effects and tissue regeneration capabilities can be engineered to achieve enhanced therapeutic outcomes. This study provides a comprehensive review of the effects of thermal stimulation on cellular and tissue regeneration. Furthermore, it highlights the applications of photothermal, magnetothermal, and electrothermal nanomaterials, and thermally responsive drug delivery systems in tissue engineering. In Addition, the bioactivities and biocompatibilities of several representative thermal nanomaterials are discussed. Finally, the challenges facing thermal nanomaterials are outlined, and future prospects in the field are presented with the aim of offering new opportunities and avenues for the utilization of thermal nanomaterials in tissue regeneration.

Bioactive Glass in Tissue Regeneration: Unveiling Recent Advances in Regenerative Strategies and Applications

Bioactive glass (BG) is a class of biocompatible, biodegradable, multifunctional inorganic glass materials, which is successfully used for orthopedic and dental applications, with several products already approved for clinical use. Apart from exhibiting osteogenic properties, BG is also known to be angiogenic and antibacterial. Recently, BG's role in immunomodulation has been gradually revealed. While the therapeutic effect of BG is mostly reported in the context of bone and skin-related regeneration, its application in regenerating other tissues/organs, such as muscle, cartilage, and gastrointestinal tissue, has also been explored recently. The strategies of applying BG have also expanded from powder or cement form to more advanced strategies such as fabrication of composite polymer-BG scaffold, 3D printing of BG-loaded scaffold, and BG-induced extracellular vesicle production. This review presents a concise overview of the recent applications of BG in regenerative medicine. Various regenerative strategies of BG will be first introduced. Next, the applications of BG in regenerating various tissues/organs, such as bone, cartilage, muscle, tendon, skin, and gastrointestinal tissue, will be discussed. Finally, clinical applications of BG for tissue regeneration will be summarized, and future challenges and directions for the clinical translation of BG will be outlined.

Antimicrobial materials based on photothermal action and their application in wound treatment

Considering the increasing abundance of antibiotic-resistant bacteria, novel antimicrobial approaches need to be investigated. Photothermal therapy (PTT), an innovative noninvasive therapeutic technique, has demonstrated significant potential in addressing drug-resistant bacteria and bacterial biofilms. However, when used in isolation, PTT requires higher-temperature conditions to effectively eradicate bacteria, thereby potentially harming healthy tissues and inducing new inflammation. This study aims to present a comprehensive review of nanomaterials with intrinsic antimicrobial properties, antimicrobial materials relying on photothermal action, and nanomaterials using drug delivery antimicrobial action, along with their applications in antimicrobials. Additionally, the synergistic mechanisms of these antimicrobial approaches are elucidated. The review provides a reference for developing multifunctional photothermal nanoplatforms for treating bacterially infected wounds.

Amoeba-Inspired Soft Robot for Integrated Tumor/Infection Therapy and Painless Postoperative Drainage

Tumor recurrence and wound infection are devastating complications of wide excision surgery for melanoma, and deep postoperative wound drainage typically increases pain. An amoeba-inspired magnetic soft robot (ASR) with switchable dormant and active phases is developed to address the aforementioned challenges. The dormant ASR supports wounds through its solid-like elasticity and regulates reactive oxygen species (ROS) levels bidirectionally, promoting healing in infected wounds and eliminating residual tumors. It solves the challenge caused by the contradictory need for ROS scavenging in wound healing and ROS amplification in tumor/infection management. The active ASR removes absorbed wound exudate by crawling out from irregular wounds; interestingly, this crawling motion prevents damage to fragile tissues and alleviates wound pain via "non-direct friction." More importantly, ASR switches different states in response to an alternating magnetic field owing to its magnetothermal properties, and this process also exerts synergistic antitumor and bacteriostatic effects. Due to the appropriate mechanical structure (cohesive force) of ASR, the content of magnetic nanoparticles required to drive the ASR is ten-fold lower than that of conventional magnetic soft robots, enabling in vivo degradation. These outcomes highlight the vantage of the ASR for treating post-tumor excision wounds and underscore their potential for clinical application.

Living photosynthetic microneedle patches for in situ oxygenation and postsurgical melanoma therapy

Surgical excision remains the principal treatment for melanoma, while tumor recurrence and delayed wound healing often occur due to the residual tumor cells and hypoxic microenvironment in the postoperative skin wounds. Herein, we present a living photosynthetic microneedle (MN) patch (namely MA/CM@MN) loaded with microalgae (MA) and cuttlefish melanin (CM) for postsurgical melanoma therapy and skin wound healing. Benefiting from the oxygenic photosynthesis of the alive MA in the MN base, the MA/CM@MN can generate oxygen under light exposure, thus facilitating skin cell proliferation and protecting cells against hypoxia-induced cell death. In addition, with CM nanoparticles embedded in the MN tips, the MA/CM@MN can be effectively heated up under near-infrared (NIR) irradiation, contributing to a strong tumor killing efficacy on melanoma cells in vitro. Further experiments demonstrate that the NIR-irradiated MA/CM@MN effectively prevents local tumor recurrence and simultaneously promotes the healing of tumor-induced wounds after incomplete tumor resection in melanoma-bearing mice, probably because the MA/CM@MN can inhibit tumor cell proliferation, stimulate tumor cell apoptosis, and mitigate tissue hypoxia in light. These results indicate that the living photosynthetic MN patch offers an effective therapeutic strategy for postoperative cancer therapy and wound healing applications.

Multifunctional bioactive glass nanoparticles: surface-interface decoration and biomedical applications

Developing bioactive materials with multifunctional properties is crucial for enhancing their biomedical applications in regenerative medicine. Bioactive glass nanoparticle (BGN) is a new generation of biomaterials that demonstrate high biocompatibility and tissue-inducing capacity. However, the hard nanoparticle surface and single surface property limited their wide biomedical applications. In recent years, the surface functional strategy has been employed to decorate the BGN and improve its biomedical applications in bone tissue repair, bioimaging, tumor therapy and wound repair. This review summarizes the progress of surface-interface design strategy, customized multifunctional properties and biomedical applications in detail. We also discussed the current challenges and further development of multifunctional BGN to meet the requirements of various biomedical applications.

A novel mussel-inspired desensitizer based on radial mesoporous bioactive nanoglass for the treatment of dentin exposure: An in vitro study

OBJECTIVES

The dentin exposure always leads to dentin hypersensitivity and the acid-resistant/abrasion-resistant stability of current therapeutic approaches remain unsatisfatory. Inspired by the excellent self-polymerization/adherence activity of mussels and the superior mineralization ability of bioactive glass, a novel radial mesoporous bioactive nanoglass coated with polydopamine (RMBG@PDA) was developed for prevention and management of dentin hypersensitivity.

METHODS

Radial mesoporous bioactive nanoglass (RMBG) was synthesized by the sol-gel process combined with the cetylpyridine bromide template self-assembly technique. RMBG@PDA was synthesized by a self-polymerization process involving dopamine and RMBG in an alkaline environment. Then, the nanoscale morphology, chemical structure, crystalline phase and Zeta potential of RMBG and RMBG@PDA were characterized. Subsequently, the ion release ability, bioactivity, and cytotoxicity of RMBG and RMBG@PDA in vitro were investigated. Moreover, an in vitro experimental model of dentin hypersensitivity was constructed to evaluate the effectiveness of RMBG@PDA on dentinal tubule occlusion, including resistances against acid and abrasion. Finally, the Young's modulus and nanohardness of acid-etched dentin were also detected after RMBG@PDA treatment.

RESULTS

RMBG@PDA showed a typical nanoscale morphology and noncrystalline structure. The use of RMBG@PDA on the dentin surface could effectively occlude dentinal tubules, reduce dentin permeability and achieve excellent acid- and abrasion-resistant stability. Furthermore, RMBG@PDA with excellent cytocompatibility held the capability to recover the Young's modulus and nanohardness of acid-etched dentin.

CONCLUSION

The application of RMBG@PDA with superior dentin tubule occlusion ability and acid/abrasion-resistant stability can provide a therapeutic strategy for the prevention and the management of dentin hypersensitivity.

Ecofriendly and scalable production of bioglass using an organic calcium source enhanced bioactivity for tissue repair

The eco-friendly and scalable production of bioglass remains a challenging but attractive strategy for advancing its widespread biomedical applications. Although the sol-gel method has been considered a valuable approach for bioglass production, the application of calcium nitrate as a calcium source markedly limits its industrialization owing to environmental pollution, high administration costs, and numerous calcium-rich regions in the as-prepared bioglass. Therefore, organic Ca has been proposed as an alternative to inorganic Ca. In the current study, bioglass was successfully prepared using a novel calcium source (calcium glycerol) and was named regeneration silicon (RegeSi). The biocompatibity of bioglass was examined by performing the methyl thiazolyl tetrazolium (MTT) assay using L929 fibroblasts. The biological and tissue repair properties of RegeSi were better than those of bioglass prepared with calcium nitrate using the sol-gel or traditional melting methods. The applicability of RegeSi was validated using suitable wound healing and dental restoration models. Notably, RegeSi ensured closure of a deep wound (1.6 cm diameter, 2 mm depth) within 11 d. Moreover, RegeSi facilitated tooth repair with a blocking rate of 97.1%. More importantly, large-scale production of RegeSi was achieved at low cost, high bioactivity, and using environmental technology, reaching a capacity of 100 kg/batch.

Multifunctional Therapeutic Nanodiamond Hydrogels for Infected-Wound Healing and Cancer Therapy

Wound infection and tumor recurrence are the two main threats to cancer patients after surgery. Although researchers have developed new treatment systems to address the two significant challenges simultaneously, the potential side effects of the heavy-metal-ion-based treatment systems still severely limit their widespread application in therapy. In addition, the wounds from tumor removal compared with general operative wounds are more complex. The tumor wounds mainly exhibit more hemorrhage, larger trauma area, greater vulnerability to bacterial infection, and residual tumor cells. Therefore, a multifunctional treatment platform is urgently needed to integrate rapid hemostasis, sterilization, wound healing promotion, and antitumor functions. In this work, nanodiamonds (NDs), a material that has been well proven to have excellent biocompatibility, are added into a solution of acrylic-grafted chitosan (CEC) and oxidized hyaluronic acid (OHA) to construct a multifunctional treatment platform (CEC-OHA-NDs). The hydrogels exhibit rapid hemostasis, a wound-healing-promoting effect, excellent self-healing, and injectable abilities. Moreover, CEC-OHA-NDs can effectively eliminate bacteria and inhibit tumor proliferation by the warm photothermal effect of NDs under tissue-penetrable near-infrared laser irradiation (NIR) without cytotoxicity. Consequently, we adopt a simple and convenient strategy to construct a multifunctional treatment platform using carbon-based nanomaterials with excellent biocompatibility to promote the healing of infected wounds and to inhibit tumor cell proliferation simultaneously.

Injectable hydrogel with antimicrobial and anti-inflammatory properties for postoperative tumor wound care

Clinically, tumor removal surgery leaves irregularly shaped wounds that are susceptible to bacterial infection and further lead to excessive inflammation. Injectable hydrogel dressings with antimicrobial and anti-inflammatory properties have been recognized as an effective strategy to care for postoperative tumor wounds and prevent recurrence in recent years. In this work, we constructed a hydrogel network by ionic bonding interactions between quaternized chitosan (QCS) and epigallocatechin gallate (EGCG)-Zn complexes which were coordinated by EGCG and zinc ions. Because of the synergistic effect of QCS and EGCG-Zn, the hydrogel exhibited outstanding antimicrobial capacity (>99.9% inhibition), which could prevent infections caused byEscherichia coli and Staphylococcus aureus. In addition, the hydrogel was able to inhibit the growth of mice breast cancer cells (56.81% survival rate within 72 h) and reduce inflammation, which was attributed to the sustained release of EGCG. The results showed that the hydrogel was effective in inhibiting tumor recurrence and accelerating wound closure when applied to the postoperative tumor wounds. This study provided a simple and reliable strategy for postoperative tumor wound care using antimicrobial and anti-inflammatory injectable dressings, confirming their great potential in the field of postoperative wound dressings.

A Smart Stimulation-Deadhesion and Antimicrobial Hydrogel for Repairing Diabetic Wounds Infected with Methicillin-Resistant Staphylococcus aureus

The healing of chronic diabetic wounds is a common and significant challenge in the medical field. Despite extensive efforts, the development of hydrogel dressings with satisfactory functionality remains an ongoing concern. In this study, a multifunctional hydrogel wound dressing (PAN/Ag-PLG) with adhesion, antibacterial, hemostatic, and other properties, which can effectively repair diabetic wounds infected with methicillin-resistant Staphylococcus aureus (MRSA), is presented. The hydrogel dressing is composed of gallic acid (GA)-functionalized polylysine (PL)-reduced silver nanoparticles (Ag-PLG), oxidized hyaluronic acid (OHA), and cross-linked polyacrylic acid grafted with N-hydrosuccinimide ester. Notably, compared to most conventional wound dressing that lack adhesion or are difficult to remove, the prepared hydrogels exhibit excellent adhesion and mild stimulation-triggered detachment. In vitro and in vivo experiments reveal that the PAN/Ag-PLG hydrogel exhibits outstanding biocompatibility and antibacterial properties and promotes diabetic wound repair by reducing oxidative damage and promoting cell migration and angiogenesis. The smart PAN/Ag-PLG hydrogel reported in this study provides an approach for the potential clinical development of painless antibacterial dressings.

Recent advances in composite hydrogels: synthesis, classification, and application in the treatment of bone defects

Bone defects are often difficult to treat due to their complexity and specificity, and therefore pose a serious threat to human life and health. Currently, the clinical treatment of bone defects is mainly surgical. However, this treatment is often more harmful to patients and there is a potential risk of rejection and infection. Hydrogels have a unique three-dimensional structure that can accommodate a variety of materials, including particles, polymers and small molecules, making them ideal for treating bone defects. Therefore, emerging composite hydrogels are considered one of the most promising candidates for the treatment of bone defects. This review describes the use of different types of composite hydrogel in the treatment of bone defects. We present the basic concepts of hydrogels, different preparation techniques (including chemical and physical crosslinking), and the clinical requirements for hydrogels used to treat bone defects. In addition, a review of numerous promising designs of different types of hydrogel doped with different materials (e.g., nanoparticles, polymers, carbon materials, drugs, and active factors) is also highlighted. Finally, the current challenges and prospects of composite hydrogels for the treatment of bone defects are presented. This review will stimulate research efforts in this field and promote the application of new methods and innovative ideas in the clinical field of composite hydrogels.

Engineering Single-Component Antibacterial Anti-inflammatory Polyitaconate-Based Hydrogel for Promoting Methicillin-Resistant Staphylococcus aureus-Infected Wound Healing and Skin Regeneration

Hydrogel wound dressings play a crucial role in promoting the healing of drug-resistant bacterially infected wounds. However, their clinical application often faces challenges such as the use of numerous components, a complicated preparation process, and insufficient biological activity. Itaconic acid, known for its excellent biological and reaction activities, has not been extensively studied for the preparation of itaconic acid-based hydrogels and their application in infected wound healing. Therefore, there is a need to develop a multifunctional single-component itaconic acid-based hydrogel that is easy to synthesize and holds promising prospects for clinical use in promoting the healing of infected wounds. In this study, we present a single-component polyitaconate-based hydrogel (PICGI) with antibacterial, anti-inflammatory, and biological activity. The PICGI hydrogel demonstrates great potential in promoting healing of infected wounds and skin regeneration. It exhibits desirable thermosensitive, injectable, and adhesive properties, as well as broad-spectrum antibacterial activity and anti-inflammatory effects. Furthermore, the PICGI hydrogel is biocompatible and significantly enhances the migration and tube formation of endothelial cells. In the case of drug-resistant bacterially infected wounds, the PICGI hydrogel effectively inhibits bacterial infection and inflammation, promotes angiogenesis, and facilitates collagen deposition, thereby accelerating the healing and regeneration of the skin. This study highlights the promising application of the PICGI hydrogel as a single-component hydrogel in tissue repair associated with bacterial infection and inflammation. Moreover, the simplicity of its components, convenient preparation process, and sufficient biological activity make the PICGI hydrogel highly suitable for promotion and clinical application.

Glucose-primed PEEK orthopedic implants for antibacterial therapy and safeguarding diabetic osseointegration

Diabetic infectious microenvironment (DIME) frequently leads to a critical failure of osseointegration by virtue of its main peculiarities including typical hyperglycemia and pathogenic infection around implants. To address the plaguing issue, we devise a glucose-primed orthopedic implant composed of polyetheretherketone (PEEK), Cu-chelated metal-polyphenol network (hauberk coating) and glucose oxidase (GOx) for boosting diabetic osseointegration. Upon DIME, GOx on implants sostenuto consumes glucose to generate H2O2, and Cu liberated from hauberk coating catalyzes the H2O2 to highly germicidal •OH, which massacres pathogenic bacteria through photo-augmented chemodynamic therapy. Intriguingly, the catalytic efficiency of the coating gets greatly improved with the turnover number (TON) of 0.284 s-1. Moreover, the engineered implants exhibit satisfactory cytocompatibility and facilitate osteogenicity due to the presence of Cu and osteopromotive polydopamine coating. RNA-seq analysis reveals that the implants enable to combat infections and suppress pro-inflammatory phenotype (M1). Besides, in vivo evaluations utilizing infected diabetic rat bone defect models at week 4 and 8 authenticate that the engineered implants considerably elevate osseointegration through pathogen elimination, inflammation dampening and osteogenesis promotion. Altogether, our present study puts forward a conceptually new tactic that arms orthopedic implants with glucose-primed antibacterial and osteogenic capacities for intractable diabetic osseointegration.

Nanostructured bioactive glasses: A bird's eye view on cancer therapy

Bioactive glasses (BGs) arewell known for their successful applications in tissue engineering and regenerative medicine. Recent experimental studies have shown their potential usability in oncology, either alone or in combination with other biocompatible materials, such as biopolymers. Direct contact with BG particles has been found to cause toxicity and death in specific cancer cells (bone-derived neoplastic stromal cells) in vitro. Nanostructured BGs (NBGs) can be doped with anticancer elements, such as gallium, to enhance their toxic effects against tumor cells. However, the molecular mechanisms and intracellular targets for anticancer compositions of NBGs require further clarification. NBGs have been successfully evaluated for use in various well-established cancer treatment strategies, including cancer hyperthermia, phototherapy, and anticancer drug delivery. Existing results indicate that NBGs not only enhance cancer cell death, but can also participate in the regeneration of lost healthy tissues. However, the application of NBGs in oncology is still in its early stages, and numerous unanswered questions must be addressed. For example, the impact of the composition, biodegradation, size, and morphology of NBGs on their anticancer efficacy should be defined for each type of cancer and treatment strategy. Moreover, it should be more clearly assessed whether NBGs can shrink tumors, slow/stop cancer progression, or cure cancer completely. In this regard, the use of computational studies (in silico methods) is highly recommended to design the most effective glass formulations for cancer therapy approaches and to predict, to some extent, the relevant properties, efficacy, and outcomes. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Photothermal antibacterial materials to promote wound healing

Wound healing is a crucial process that restores the integrity and function of the skin and other tissues after injury. However, external factors, such as infection and inflammation, can impair wound healing and cause severe tissue damage. Therefore, developing new drugs or methods to promote wound healing is of great significance. Photothermal therapy (PTT) is a promising technique that uses photothermal agents (PTAs) to convert near-infrared radiation into heat, which can eliminate bacteria and stimulate tissue regeneration. PTT has the advantages of high efficiency, controllability, and low drug resistance. Hence, nanomaterial-based PTT and its related strategies have been widely explored for wound healing applications. However, a comprehensive review of PTT-related strategies for wound healing is still lacking. In this review, we introduce the physiological mechanisms and influencing factors of wound healing, and summarize the types of PTAs commonly used for wound healing. Then, we discuss the strategies for designing nanocomposites for multimodal combination treatment of wounds. Moreover, we review methods to improve the therapeutic efficacy of PTT for wound healing, such as selecting the appropriate wound dressing form, controlling drug release, and changing the infrared irradiation window. Finally, we address the challenges of PTT in wound healing and suggest future directions.

pH Switchable Nanozyme Platform for Healing Skin Tumor Wound Infected with Drug-Resistant Bacteria

Nanozymes capable of generating reactive oxygen species have recently emerged as promising treatments for wounds infected with drug-resistant bacteria, possessing a reduced possibility of inducing resistance. However, the therapeutic effect is limited by a shortage of endogenous oxy-substrates and undesirable off-target biotoxicity. Herein, a ferrocenyl coordination polymer (FeCP) nanozyme, featuring pH switchable peroxidase (POD)- and catalase (CAT)-like activity is incorporated with indocyanine green (ICG) and calcium peroxide (CaO2 ) to fabricate an H2 O2 /O2 self-supplying system (FeCP/ICG@CaO2 ) for precise treatment of bacterial infections. At the wound site, CaO2 reacts with water to generate H2 O2 and O2 . Acting as a POD mimic under an acidic bacterial microenvironment, FeCP catalyzes H2 O2 into hydroxyl radicals to prevent infection. However, FeCP switches to CAT-like activity in neutral tissue, decomposing H2 O2 into H2 O and O2 to prevent oxidative damage and facilitate wound healing. Additionally, FeCP/ICG@CaO2 shows photothermal therapy capability, as ICG can emit heat under near-infrared laser irradiation. This heat assists FeCP in fully exerting its enzyme-like activity. Thus, this system achieves an antibacterial efficiency of 99.8% in vitro for drug-resistant bacteria, and effectively overcomes the main limitations of nanozyme-based treatment assays, resulting in satisfactory therapeutic effects in repairing normal and special skin tumor wounds infected with drug-resistant bacteria.

Bioactive nanoglass regulating the myogenic differentiation and skeletal muscle regeneration

Bioactive glass nanoparticles (BGNs) are widely used in the field of biomedicine, including drug delivery, gene therapy, tumor therapy, bioimaging, molecular markers and tissue engineering. Researchers are interested in using BGNs in bone, heart and skin regeneration. However, there is inadequate information on skeletal muscle tissue engineering, limited information on the biological effects of BGNs on myoblasts, and the role of bioactive glass composite materials on myogenic differentiation is unknown. Herein, we report the effects of BGNs with different compositions (60Si-BGN, 80Si-BGN, 100Si-BGN) on the myogenic differentiation in C2C12 cells and in vivo skeletal tissue regeneration. The results showed that 80Si-BGN could efficiently promote the myogenic differentiation of C1C12 cells, including the myotube formation and myogenic gene expression. The in vivo experiment in a rat skeletal muscle defect model also confirmed that 80Si-BGN could significantly improve the complete regeneration of skeletal muscle tissue during 4 weeks implantation. This work firstly demonstrated evidence that BGN could be the bioactive material in enhancing skeletal muscle regeneration.

Multifunctional antibacterial bioactive nanoglass hydrogel for normal and MRSA infected wound repair

Large-scale skin damage brings potential risk to patients, such as imbalance of skin homeostasis, inflammation, fluid loss and bacterial infection. Moreover, multidrug resistant bacteria (MDRB) infection is still a great challenge for skin damage repair. Herein, we developed an injectable self-healing bioactive nanoglass hydrogel (FABA) with robust antibacterial and anti-inflammatory ability for normal and Methicillin-resistant Staphylococcus aureus (MRSA) infected skin wound repair. FABA hydrogel was fabricated facilely by the self-crosslinking of F127-CHO (FA) and alendronate sodium (AL)-decorated Si-Ca-Cu nanoglass (BA). FABA hydrogel could significantly inhibit the growth of Staphylococcus aureus, Escherichia coli and MRSA in vitro, while showing good cytocompatibility and hemocompatibility. In addition, FABA hydrogel could inhibit the expression of proinflammatory factor TNF-α and enhance the expression of anti-inflammatory factor IL-4/ IL-10. Based on its versatility, FABA hydrogel could complete wound closure efficiently (75% at day 3 for normal wound, 70% at day 3 for MRSA wound), which was almost 3 times higher than control wound, which was related with the decrease of inflammatory factor in early wound. This work suggested that FABA hydrogel could be a promising dressing for acute and MRSA-infected wound repair.

Sandwich-Structured Implants to Obstruct Multipath Energy Supply and Trigger Self-Enhanced Hypoxia-Initiated Chemotherapy Against Postsurgical Tumor Recurrence and Metastasis

As a currently common strategy to treat cancer, surgical resection may cause tumor recurrence and metastasis due to residual postoperative tumors. Herein, an implantable sandwich-structured dual-drug depot is developed to trigger a self-intensified starvation therapy and hypoxia-induced chemotherapy sequentially. The two outer layers are 3D-printed using a calcium-crosslinked mixture ink containing soy protein isolate, polyvinyl alcohol, sodium alginate, and combretastatin A4 phosphate (CA4P). The inner layer is one patch of poly (lactic-co-glycolic acid)-based electrospun fibers loaded with tirapazamine (TPZ). The preferentially released CA4P destroys the preexisting blood vessels and prevents neovascularization, which obstructs the external energy supply to cancer cells but aggravates hypoxic condition. The subsequently released TPZ is bioreduced to cytotoxic benzotriazinyl under hypoxia, further damaging DNA, generating reactive oxygen species, disrupting mitochondria, and downregulating hypoxia-inducible factor 1α, vascular endothelial growth factor, and matrix metalloproteinase 9. Together these processes induce apoptosis, block the intracellular energy supply, counteract the disadvantage of CA4P in favoring intratumor angiogenesis, and suppress tumor metastasis. The in vivo and in vitro results and the transcriptome analysis demonstrate that the postsurgical adjuvant treatment with the dual-drug-loaded sandwich-like implants efficiently inhibits tumor recurrence and metastasis, showing great potential for clinical translation.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Engineered photoresponsive biohybrids for tumor therapy

Engineered biohybrids have recently emerged as innovative biomimetic platforms for cancer therapeutic applications. Particularly, engineered photoresponsive biohybrids hold tremendous potential against tumors due to their intriguing biomimetic properties, photoresponsive ability, and enhanced biotherapeutic functions. In this review, the design principles of engineered photoresponsive biohybrids and their latest progresses for tumor therapy are summarized. Representative engineered photoresponsive biohybrids are highlighted including biomolecules-associated, cell membrane-based, eukaryotic cell-based, bacteria-based, and algae-based photoresponsive biohybrids. Representative tumor therapeutic modalities of the engineered photoresponsive biohybrids are presented, including photothermal therapy, photodynamic therapy, synergistic therapy, and tumor therapy combined with tissue regeneration. Moreover, the challenges and future perspectives of these photoresponsive biohybrids for clinical practice are discussed.

Bioinspired Piezoelectric Periosteum to Augment Bone Regeneration via Synergistic Immunomodulation and Osteogenesis

Ideal periosteum materials are required to participate in a sequence of bone repair-related physiological events, including the initial immune response, endogenous stem cell recruitment, angiogenesis, and osteogenesis. However, conventional tissue-engineered periosteal materials have difficulty achieving these functions by simply mimicking the periosteum via structural design or by loading exogenous stem cells, cytokines, or growth factors. Herein, we present a novel biomimetic periosteum preparation strategy to comprehensively enhance the bone regeneration effect using functionalized piezoelectric materials. The resulting biomimetic periosteum possessing an excellent piezoelectric effect and improved physicochemical properties was prepared using a biocompatible and biodegradable poly(3-hydroxybutyric acid-co-3-hydrovaleric acid) (PHBV) polymer matrix, antioxidized polydopamine-modified hydroxyapatite (PHA), and barium titanate (PBT), which were further incorporated into the polymer matrix to fabricate a multifunctional piezoelectric periosteum by a simple one-step spin-coating method. The addition of PHA and PBT dramatically enhanced the physicochemical properties and biological functions of the piezoelectric periosteum, resulting in improved surface hydrophilicity and roughness, enhanced mechanical performance, tunable degradation behavior, and stable and desired endogenous electrical stimulations, which is conducive to accelerating bone regeneration. Benefiting from endogenous piezoelectric stimulation and bioactive components, the as-fabricated biomimetic periosteum demonstrated favorable biocompatibility, osteogenic activity, and immunomodulatory functions in vitro, which not only promoted adhesion, proliferation, and spreading as well as osteogenesis of mesenchymal stem cells (MSCs) but also effectively induced M2 macrophage polarization, thereby suppressing reactive oxygen species (ROS)-induced inflammatory reactions. Through in vivo experiments, the biomimetic periosteum with endogenous piezoelectric stimulation synergistically accelerated the formation of new bone in a rat critical-sized cranial defect model. The whole defect was almost completely covered by new bone at 8 weeks post treatment, with a thickness close to that of the host bone. Collectively, with its favorable immunomodulatory and osteogenic properties, the biomimetic periosteum developed here represents a novel method to rapidly regenerate bone tissue using piezoelectric stimulation.

Engineering Multifunctional Polyether Ether Ketone Implant: Mechanics-Adaptability, Biominerialization, Immunoregulation, Anti-Infection, Osteointegration, and Osteogenesis

Polyether ether ketone (PEEK) has become one of the most promising polymer implants in bone orthopedics, due to the biocompatibility, good processability, and radiation resistance. However, the poor mechanics-adaptability/osteointegration/osteogenesis/antiinfection limits the long-term in vivo applications of PEEK implants. Herein, a multifunctional PEEK implant (PEEK-PDA-BGNs) is constructed through in situ surface deposition of polydopamine-bioactive glass nanoparticles (PDA-BGNs). PEEK-PDA-BGNs exhibit good performance on osteointegration and osteogenesis in vitro and in vivo, due to their multifunctional properties including mechanics-adaptability, biominerialization, immunoregulation, anti-infection, and osteoinductive activity. PEEK-PDA-BGNs can show the bone tissue-adaptable mechanic surface and induce the rapid biomineralization (apatite formation) under a simulated body solution. Additionally, PEEK-PDA-BGNs can induce the M2 phenotype polarization of macrophages, reduce the expression of inflammatory factors, promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and improve the osseointegration and osteogenesis ability of the PEEK implant. PEEK-PDA-BGNs also show good photothermal antibacterial activity and can kill 99% of Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA), suggesting their potential antiinfection ability. This work suggests that PDA-BGNs coating is probably a facile strategy to construct multifunctional (biomineralization, antibacterial, immunoregulation) implants for bone tissue replacement.

Multi-layer-structured bioactive glass nanopowder for multistage-stimulated hemostasis and wound repair

Current treatments for full-thickness skin injuries are still unsatisfactory due to the lack of hierarchically stimulated dressings that can integrate the rapid hemostasis, inflammation regulation, and skin tissue remodeling into the one system instead of single-stage boosting. In this work, a multilayer-structured bioactive glass nanopowder (BGN@PTE) is developed by coating the poly-tannic acid and ε-polylysine onto the BGN via facile layer-by-layer assembly as an integrative and multilevel dressing for the sequential management of wounds. In comparison to BGN and poly-tannic acid coated BGN, BGN@PTE exhibited the better hemostatic performance because of its multiple dependent approaches to induce the platelet adhesion/activation, red blood cells (RBCs) aggregation and fibrin network formation. Simultaneously, the bioactive ions from BGN facilitate the regulation of the inflammatory response while the poly-tannic acid and antibacterial ε-polylysine prevent the wound infection, promoting the wound healing during the inflammatory stage. In addition, BGN@PTE can serve as a reactive oxygen species scavenger, alleviate the oxidation stress in wound injury, induce the cell migration and angiogenesis, and promote the proliferation stage of wound repair. Therefore, BGN@PTE demonstrated the significantly higher wound repair capacity than the commercial bioglass dressing Dermlin™. This multifunctional BGN@PTE is a potentially valuable dressing for full-thickness wound management and may be expected to extend to the other wounds therapy.

Nanocomposite multifunctional hyaluronic acid hydrogel with photothermal antibacterial and antioxidant properties for infected wound healing

Bacterial infection and subsequent reactive oxygen species (ROS) damage are major factors that delay wound healing in infected skin. Recently, photothermal therapy (PTT), as a new antibacterial method, has shown great advantages in the treatment of infected skin wound. Antibacterial and antioxidant hydrogels can reduce bacterial colonization and infection, scavenge ROS, relieve inflammation, and accelerate wound healing. In this study, an enzyme-crosslinked hyaluronic acid-tyramine (HT) hydrogel loaded with antioxidant and photothermal silver nanoparticles (AgNPs), named HTA, was developed as functional wound dressing to promote the infected skin wound healing. Natural antioxidant tannic acids (TA) were used as both reducing and stabilizing agents to facilely synthesize the silver nanoparticles capped with TA (AgNPs@TA). The incorporation of AgNPs@TA significantly enhanced the antioxidant, antibacterial, photothermal antibacterial, adhesive, and hemostatic abilities of the resulted HTA hydrogel. Besides, HTA hydrogel has rapid gelation, well injection and biocompatibility. In vivo results on the Staphylococcus aureus and Escherichia coli co-infected mouse skin wound model showed that HTA_0.4 (containing 0.4 mg/mL AgNPs@TA) hydrogel combined with near infrared ray radiation highly alleviated inflammation, promoted angiogenesis, and accelerated the healing process. Therefore, this nanocomposite hydrogel wound dressing with antibacterial and antioxidant capabilities has great application potential in the treatment of infected skin wounds.

Microenvironment-Adaptive Nanozyme for Accelerating Drug-Resistant Bacteria-Infected Wound Healing

Reactive oxygen species (ROS) are favorable for antibacterial infection but their overproduction results in serious inflammatory response and aggravates the hypoxic state of the wound tissue, which is detrimental to healing stages of proliferation and remodeling. Here, an atomic-dispersion Fe-doped oxygen-deficient molybdenum oxide MoO_{3- X} (ADFM) bifunctional nanozyme, featuring implanted peroxidase-like and enhanced catalase-like activity, is developed for decomposing H₂ O₂ into strongly oxidizing hydroxyl radicals (•OH) for prevention of bacterial infection and into plentiful O₂ for healing stages. Therein, the introduction of Fe into MoO_{3- X} primarily produces an asymmetric electron density difference by elongating the bond length between metal atoms, synchronously stabilizing adsorption of •OH and weakening the adsorption of O₂ . ADFM also shows unimaginably high aqueous dispersity and pH-adaptive ROS regulation in the wound microenvironment, both of which are favorable for ADFM to fully exert enzyme-like activity for timely antibacterial and efficient wound-healing action. ADFM thus achieves efficient healing of drug-resistant bacteria-infected wounds in vivo, at an ultralow dosage of 30 µg mL^-1 against 10⁶ CFU mL^-1 extended spectrum β-lactamases-producing Escherichia coli, exhibiting a wound-healing efficiency of ≈10 mm² per day, which sets a benchmark among these noble-metal-free nanozyme-based wound-healing agents.

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.

Precision medicine strategies for spinal degenerative diseases: Injectable biomaterials with in situ repair and regeneration

As the population ages, spinal degeneration seriously affects quality of life in middle-aged and elderly patients, and prevention and treatment remain challenging for clinical surgeons. In recent years, biomaterials-based injectable therapeutics have attracted much attention for spinal degeneration treatment due to their minimally invasive features and ability to perform precise repair of irregular defects. However, the precise design and functional control of bioactive injectable biomaterials for efficient spinal degeneration treatment remains a challenge. Although many injectable biomaterials have been reported for the treatment of spinal degeneration, there are few reviews on the advances and effects of injectable biomaterials for spinal degeneration treatment. This work reviews the current status of the design and fabrication of injectable biomaterials, including hydrogels, bone cements and scaffolds, microspheres and nanomaterials, and the current progress in applications for treating spinal degeneration. Additionally, registered clinical trials were also summarized and key challenges and clinical translational prospects for injectable materials for the treatment of spinal degenerative diseases are discussed.

Engineering elastic bioactive composite hydrogels for promoting osteogenic differentiation of embryonic mesenchymal stem cells

The development of bioactive materials with good mechanical properties and promotion of stem cell osteogenic differentiation has important application prospects in bone tissue engineering. In this paper, we designed a novel organic‒inorganic composite hydrogel (FPIGP@BGN-Sr) utilizing diacrylated F127 (DA-PF127), β-glycerophosphate-modified polyitaconate (PIGP) and strontium-doped bioactive glass nanoparticles (BGN-Sr) through free radical polymerization and coordination interactions and then evaluated its promoting effect on the osteogenic differentiation of mouse embryonic mesenchymal stem cells in detail. The results showed that the FPIGP@BGN-Sr hydrogel exhibited a controlled storage modulus by changing the amount of BGN-Sr. Notably, the FPIGP@BGN-Sr hydrogel possessed excellent elastic ability with a compressive strain of up to 98.6% and negligible change in mechanical properties after 10 cycles of compression. In addition, the FPIGP@BGN-Sr hydrogel had good cytocompatibility, maintained the activity and proliferation of mouse embryonic mesenchymal stem cells (C3H10T1/2), and effectively enhanced the activity of alkaline phosphatase, osteogenic gene expression and biomineralization ability of the cells. In conclusion, the excellent mechanical properties and osteogenic biological activity of the FPIGP@BGN-Sr hydrogel make it a promising organic‒inorganic composite bioactive material for stem cell-based bone regeneration.

Multi-functional wound dressings based on silicate bioactive materials

Most traditional wound dressings passively offer a protective barrier for the wounds, which lacks the initiative in stimulating tissue regeneration. In addition, cutaneous wound healing is usually accompanied by various complicated conditions, including bacterial infection, skin cancer, and damaged skin appendages, bringing further challenges for wound management in clinic. Therefore, an ideal wound dressing should not only actively stimulate wound healing but also hold multi-functions for solving problems associated with different specific wound conditions. Recent studies have demonstrated that silicate bioceramics and bioglasses are one type of promising materials for the development of wound dressings, as they can actively accelerate wound healing by regulating endothelial cells, dermal fibroblasts, macrophages, and epidermal cells. In particular, silicate-based biomaterials can be further functionalized by specific structural design or doping with functional components, which endow materials with enhanced bioactivities or expanded physicochemical properties such as photothermal, photodynamic, chemodynamic, or imaging properties. The functionalized materials can be used to address wound healing with different demands including but not limited to antibacterial, anticancer, skin appendages regeneration, and wound monitoring. In this review, we summarized the current research on the development of silicate-based multi-functional wound dressings and prospected the development of advanced wound dressings in the future.

Bioactive anti-inflammatory antibacterial metformin-contained hydrogel dressing accelerating wound healing

Highly efficient wound healing and skin regeneration remain a challenge. Long-term inflammation and bacterial infection can inhibit the healing process and lead to the scar formation. Here, we report a hydrogel (FEM) formed by self-assembly of ε-poly-l-lysine-F127-ε-poly-l-lysine (EPL-F127-EPL) and metformin for wound repair. Especially, the role of metformin-based antibacterial hydrogel in wound healing and repair was investigated for the first time. FEM has inherent multifunctional properties, including controlled metformin release, anti-inflammatory and antibacterial activity, temperature responsiveness, injectable and self-healing capabilities. The in vivo results showed that FEM dressings accelerated the wound healing by stimulating the angiogenesis process of the wound tissue and anti-inflammation. This study shows that the multifunctional metformin-contained hydrogel scaffolds could enhance the wound repair through the anti-inflammation and accelerated angiogenesis, which could also expand the biomedical applications of metformin-based biomaterials.

Tannin-Bridged Magnetic Responsive Multifunctional Hydrogel for Enhanced Wound Healing by Mechanical Stimulation Induced Early Vascularization

Wound healing is a complex process. Wound repair material requires multiple functionalities, such as anti-inflammatory, antibacterial, angiogenesis, pro-proliferation, and remodeling. To achieve rapid tissue regeneration, magnetic field-assisted therapy has become...