Zeolite imidazolate framework-8 in bone regeneration: A systematic review

Advances of functional nanomaterials as either therapeutic agents or delivery systems in the treatment of periodontitis

Periodontitis is a common chronic inflammatory disease primarily caused by pathogenic microorganisms in the oral cavity. Without appropriate treatments, it may lead to the gradual destruction of the supporting tissues of the teeth. While current treatments can alleviate symptoms, they still have limitations, particularly in eliminating pathogenic bacteria, promoting periodontal tissue regeneration, and avoiding antibiotic resistance. In recent years, functional nanomaterials have shown great potential in the treatment of periodontitis due to their unique physicochemical and biological properties. This review summarizes various functionalization strategies of nanomaterials and explores their potential applications in periodontitis treatment, including metal-based nanoparticles, carbon nanomaterials, polymeric nanoparticles, and exosomes. The mechanisms and advances in antibacterial effects, immune regulation, reactive oxygen species (ROS) scavenging, and bone tissue regeneration are discussed in detail. In addition, the challenges and future directions of applying nanomaterials in periodontitis therapy are also discussed.

Dynamic multistage nanozyme hydrogel reprograms diabetic wound microenvironment: synergistic oxidative stress alleviation and mitochondrial restoration

Chronic diabetic wounds remain a significant clinical challenge due to persistent bacterial infections, oxidative stress, impaired angiogenesis, and mitochondrial dysfunction. Traditional therapies often fail to address these interrelated pathological factors, highlighting the urgent need for innovative solutions. Here, we present a Mn-ZIF@GOx/BC (MZGB) hydrogel system, where Mn-ZIF@GOx (MZG) nanozymes are successfully integrated into a bacterial cellulose (BC) hydrogel via hydrogen bonding and electrostatic interactions. The MZGB hydrogel lowers wound pH by oxidizing excess glucose into gluconic acid. It exhibits strong ROS scavenging capabilities through its superoxide dismutase and catalase-like activities, while simultaneously providing oxygen. By restoring redox homeostasis, it protects mitochondrial function and enhances cellular energy metabolism. By reprogramming macrophages, MZGB creates a favorable immune microenvironment, significantly promoting angiogenesis through paracrine mechanisms. This facilitates cell-to-cell communication, forming a positive feedback loop. Moreover, MZGB demonstrates ROS-independent antibacterial properties. BC hydrogel ensures adhesion and moisture regulation, forming a protective barrier and maintaining an optimal wound environment. This multifunctional hydrogel represents a promising nanotherapeutic approach for efficiently treating diabetic wounds by precisely regulating the wound microenvironment.

3D bioprinted biomimetic MOF-functionalized hydrogel scaffolds for bone regeneration: Synergistic osteogenesis and osteoimmunomodulation

Critical-size bone defects remain a significant clinical challenge. The lack of endogenous stem cells with osteogenic differentiation potential in the defect area, combined with the inflammatory responses induced by scaffold implantation, highlights the need for biomaterials that can deliver stem cells and possess inflammatory regulation properties. In this study, we developed a 3D bioprinted gelatin methacrylate (GelMA) hydrogel scaffold modified with luteolin-loaded ZIF-8 (LUT@ZIF-8) nanoparticles, designed to deliver bone marrow mesenchymal stem cells (BMSCs) to the defect site and release bioactive components that promote osteogenesis and modulate the immune microenvironment. The LUT@ZIF-8/GelMA hydrogel scaffolds demonstrated excellent physical properties and biocompatibility. The sustained release of luteolin and zinc ions from the LUT@ZIF-8 nanoparticles conferred antibacterial, osteoinductive, and inflammatory regulation effects. The immune microenvironment modulated by LUT@ZIF-8/GelMA hydrogel scaffolds facilitated osteogenic differentiation of BMSCs. Furthermore, in vivo experiments confirmed the osteogenic and inflammatory regulation capabilities of the LUT@ZIF-8/GelMA hydrogel scaffolds. In conclusion, the 3D bioprinted LUT@ZIF-8/GelMA hydrogel scaffolds exhibit osteoimmunomodulatory properties, presenting a promising strategy for the treatment of bone defects.

Synthesis methods, structure, and recent trends of ZIF-8-based materials in the biomedical field

Zeolitic imidazolate framework-8 (ZIF-8) is a highly porous material with remarkable structural properties and high drug-loading capacity, and hence this material presents as an exceptional candidate for advanced drug delivery systems. Herein, we comprehensively review the recent developments in ZIF-8 synthesis techniques and critically discuss innovative approaches such as the use of green solvents and advanced methods such as microwave- and ultrasound-assisted syntheses. The multifunctional applications of ZIF-8-based biomaterials in biomedical engineering are critically explored with their pivotal roles in antibacterial and anticancer therapies, drug delivery systems, bone tissue engineering, and diagnostic platforms such as biosensing and bioimaging. The present review also clarifies some innovations of ZIF-8-based materials in pH-sensitive and glucose-responsive drug delivery systems and scaffolds for bone regeneration. Despite these promising advancements, we analyze critical concerns, such as the release of Zn(ii) ions, potential cytotoxicity, and biocompatibility challenges, which remain significant hurdles to the broader adoption of ZIF-8. Addressing these outlined challenges may be necessary in realizing the potential of ZIF-8 in biomedical applications.

pH-Responsive silk protein/ZIF-8@bacitracin composite coating on strontium-doped nanorod surface for combating implant-associated infections

Titanium-based bone repair materials often face bacterial infections, resulting in inflammation and impaired osseointegration. To address this issue, we developed a multifunctional coating by encapsulating bacitracin within a metal-organic framework (ZIF-8@B) and incorporating it into a strontium-doped titanium dioxide nanorod (STN) structure using silk protein (SF). This coating, termed STN-SF/ZIF-8@B, was applied to titanium surfaces. It demonstrated outstanding hydrophilicity, corrosion resistance, hemocompatibility, and biosafety. The synergistic effects of bacitracin and Zn2+ achieved over 80 % inhibition against both E. coli and S. aureus. Additionally, STN-SF/ZIF-8@B effectively reprogrammed inflammatory macrophages into an anti-inflammatory M2 phenotype. The combined actions of Sr2+ and Zn2+ significantly enhanced the migration, lumen formation, and expression of angiogenic growth factors in HUVEC. Moreover, STN-SF/ZIF-8@B upregulated the expression of genes and proteins related to osteogenesis, promoting the osteogenic differentiation of MC3T3-E1 cells. In vivo experiments utilizing a rat bone defect model revealed that STN-SF/ZIF-8@B exhibited superior anti-inflammatory, antibacterial, pro-angiogenic, and osteogenic properties. This study provided a promising approach for the development of advanced biomaterials that simultaneously address infection control, immune modulation, angiogenesis, and bone regeneration, offering significant potential for improving the outcomes of bone defect repair in clinical applications.

Artificial Bone Materials for Infected Bone Defects: Advances in Antimicrobial Functions

Infected bone defects, caused by bacterial contamination following disease or injury, result in the partial loss or destruction of bone tissue. Traditional bone transplantation and other clinical approaches often fail to address the therapeutic complexities of these conditions effectively. In recent years, advanced biomaterials have attracted significant attention for their potential to enhance treatment outcomes. This review explores the pathogenic mechanisms underlying infected bone defects, including biofilm formation and bacterial internalization into bone cells, which allow bacteria to evade the host immune system. To control bacterial infection and facilitate bone repair, we focus on antibacterial materials for bone regeneration. A detailed introduction is given on intrinsically antibacterial materials (e.g., metal alloys, oxide materials, carbon-based materials, hydroxyapatite, chitosan, and Sericin). The antibacterial functionality of bone repair materials can be enhanced through strategies such as the incorporation of antimicrobial ions, surface modification, and the combined use of multiple materials to treat infected bone defects. Key innovations discussed include biomaterials that release therapeutic agents, functional contact biomaterials, and bioresponsive materials, which collectively enhance antibacterial efficacy. Research on the clinical translation of antimicrobial bone materials has also facilitated their practical application in infection prevention and bone healing. In conclusion, advancements in biomaterials provide promising pathways for developing more biocompatible, effective, and personalized therapies to reconstruct infected bone defects.

Functionalized zeolite regulates bone metabolic microenvironment

The regulation of bone metabolic microenvironment imbalances in diseases such as osteoporosis, bone defects, infections, and tumors remains a significant challenge in orthopedics. Therefore, it has become urgent to develop biomaterials with effective bone metabolic microenvironmental regulatory functions. Zeolites, as advanced biomedical materials, possess distinctive physicochemical properties such as multi-level pore structures, adjustable frameworks, easily modifiable surfaces, and excellent adsorption capabilities. These advantageous characteristics give zeolites broad application prospects in regulating the bone metabolic microenvironment. Therefore, this paper first classifies zeolites used to regulate the bone metabolic microenvironment based on their topological structures and compositional frameworks. Subsequently, it provides a detailed description of modification strategies for zeolite materials aimed at regulating this microenvironment. Next, a comprehensive summary was provided on the preparation strategies for zeolite materials aimed at regulating the bone metabolic microenvironment. Additionally, the paper focuses on the specific applications of zeolite materials in conditions of bone metabolic imbalance, such as osteoporosis, bone defects, orthopedic infections, and bone tumors, highlighting their potential in enhancing osteogenic microenvironments, controlling infections, and treating bone tumors. Finally, it outlines the prospects and challenges associated with the application of zeolites in regulating the bone metabolic microenvironment. This review comprehensively summarizes zeolites used for bone metabolic regulation, aiming to provide guidance for future research and application development.

Chitosan and gelatin based sprayable hydrogels incorporating photothermal and long-acting antibiotic sterilization for infected wound management with shape adaptability

Severe skin damage resulting from acute trauma is often accompanied by uncontrolled bleeding, microbial infections, and delayed wound healing. Herein, multifunctional sprayable hydrogels (CT-CS-ZIF@CIP Gel) were developed for wound management by incorporating antibacterial nanoplatforms (CT-CS-ZIF@CIP) into photocurable gels consisting of chitosan methacrylate and gallic acid grafted gelatin. The nanoplatform was initially constructed by sequentially loading Cu2Se (CS) and ciprofloxacin-decorated zeolitic imidazolate framework-8 (ZIF@CIP) onto Cu-doped Ti MOF (CT), in which CS served as a photothermal agent, ZIF enabled pH-responsive release of CIP, and CT acted as carriers for CS and ZIF@CIP. The hydrogel precursor can be sprayed onto wound surface and photocured quickly, allowing hydrogel to fit the wound shape and form a protective barrier onsite. The resultant hydrogel exhibited excellent hemostatic ability, adhesion properties, cytocompatibility and toxin adsorption capacity. By integrating CS for short-term photothermal therapy with CIP for long-acting chemotherapy, the CT-CS-ZIF@CIP Gel demonstrated 100 % sterilization of three bacterial strains. Furthermore, moderate release of zinc and copper ions promoted wound healing. The therapeutic efficacy of hydrogel was validated in an infected cutaneous mouse model. Overall, this work presents a versatile sprayable hydrogel that can be flexibly applied to irregular dynamic wounds for safe and effective wound management.

Macrophage membrane-encapsulated miRNA nanodelivery system for the treatment of hemophilic arthritis

Hemophilic arthritis (HA) is one of the most pathologically altered joint diseases. Specifically, periodic spontaneous hemorrhage-induced hyperinflammation of the synovium and irreversible destruction of the cartilage are the main mechanisms that profoundly affect the behavioral functioning and quality of life of patients. In this study, we isolated and characterized platelet-rich plasma-derived exosomes (PRP-exo). We performed microRNA (miRNA) sequencing and bioinformatics analysis on these exosomes to identify the most abundant miRNA, miR-451a. Following this, we developed an M@ZIF-8@miR nanotherapeutic system that utilizes nanoscale zeolitic imidazolate framework (ZIF) as a carrier for miRNA delivery, encapsulated within M2 membranes to enhance its anti-inflammatory effects. In vitro and in vivo studies demonstrated that M@ZIF-8@miR significantly reduced pro-inflammatory cytokines, controlled synovial inflammation, and achieved potent therapeutic efficacy by reducing joint damage. We suggest that the ability of M@ZIF-8@miR nanocomposites to inhibit pro-inflammatory cytokines, enhance cellular uptake, and exhibit good endosomal escape properties makes them promising carriers for the efficient delivery of therapeutic nucleic acid drugs. This approach delays joint degeneration and provides a promising combinatorial strategy for HA treatment.

3D-Printed Hydrogel Scaffolds Loaded with Flavanone@ZIF-8 Nanoparticles for Promoting Bacteria-Infected Wound Healing

Bacterial-infected skin wounds caused by trauma remain a significant challenge in modern medicine. Clinically, there is a growing demand for wound dressings with exceptional antibacterial activity and robust regenerative properties. To address the need, this study proposes a novel multifunctional dressing designed to combine efficient gas exchange, effective microbial barriers, and precise drug delivery capabilities, thereby promoting cell proliferation and accelerating wound healing. This work reports the development of a 3D-printed hydrogel scaffold incorporating flavanone (FLA)-loaded ZIF-8 nanoparticles (FLA@ZIF-8 NPs) within a composite matrix of κ-carrageenan (KC) and konjac glucomannan (KGM). The scaffold forms a stable dual-network structure through the chelation of KC with potassium ions and intermolecular hydrogen bonding between KC and KGM. This dual-network structure not only enhances the mechanical stability of the scaffold but also improves its adaptability to complex wound environments. In mildly acidic wound conditions, FLA@ZIF-8 NPs release Zn2+ and flavanone in a controlled manner, providing sustained antibacterial effects and promoting wound healing. In vivo studies using a rat full-thickness infected wound model demonstrated that the FLA@ZIF-8/KC@KGM hydrogel scaffold significantly accelerated wound healing, showcasing its superior performance in the treatment of infected wounds.

PMA-Zeolite: Chemistry and Diverse Medical Applications

Numerous scientific studies have been conducted in recent decades with the aim to study targeted application of zeolites in various industries, ecology, agronomy and medicine. The biggest advances, however, have been documented in medical and veterinary research of the natural zeolite, clinoptilolite. Although the exact biological mechanisms of action of the zeolite clinoptilolite are not completely elucidated, obtained results point to its antioxidative, immunomodulatory and detoxifying effects, the latter partially based on release of soluble and bioavailable silica forms from the surface material. The studied zeolite clinoptilolite materials have different geographical origins which confer to the physicochemical differences in the material. In addition, the production process of the material for oral applications differs between different producers which also accounts for different properties of the surface upon mechanical activation. Recently, a well-characterized zeolite clinoptilolite material, namely the PMA-zeolite, has been tested in different clinical applications and has shown potential as supportive therapy in inflammatory conditions, osteoporosis as well as during tumor chemotherapy. We accordingly present a comprehensive review of the PMA-zeolite effects in the clinical applications and discuss its probable mechanisms of effect in vivo.

Porous titanium scaffolds modified with Zeolitic Imidazolate Framework (ZIF-8) with enhanced osteogenic activity for the prevention of implant-associated infections

In this study, zeolitic imidazolate framework 8 (ZIF-8) was coated on porous Ti6Al4V scaffolds, either bare or previously modified using hydroxyapatite (HA) or HA and gelatin (HAgel), via a growing single-step method in aqueous media using two contact times at 6 h and 24 h. The coated scaffolds termed ZIF-8@Ti, ZIF-8@HA/Ti, and ZIF-8@HAgel/Ti were characterized via scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), and molecular plasma-atomic emission spectroscopy (MP-AES). In order to assess the cell proliferation rate, the cytocompatibility of the scaffolds was evaluated in primary osteoblasts (hOBs) using alamarBlue assay, while the osteoconductivity was analyzed in hOBs using a real-time approach, evaluating the expression of secreted phosphoprotein 1 (SPP1). Osteopontin, which is the protein encoded by this gene, represents the major non-collagenous bone protein that binds tightly to HA. The scaffolds were shown to be non-cytotoxic based on hOB proliferation at all time points of analysis (24 h and 72 h). In hOB cultures, the scaffolds induced the upregulation of SPP1 with different fold changes. Some selected scaffolds were assayed in vitro for their antibacterial potential against Staphylococcus epidermidis; the scaffolds coated with ZIF-8 crystals, regardless of the presence of HA and gelatin, strongly inhibited bacterial adhesion to the materials and reduced bacterial proliferation in the culture medium, demonstrating the suitable release of ZIF-8 in a bioactive form. These experiments suggest that the innovative scaffolds, tested herein, provide a good microenvironment for hOB adhesion, viability, and osteoconduction with effective prevention of S. epidermidis adhesion.