Safety and Efficacy of S53P4 Bioactive Glass in Osteomyelitis Management: A Systematic Review and Meta-Analysis

Osteomyelitis remains a difficult-to-treat bone infection due to its high recurrence risk, complex surgical demands, and rising rates of multidrug-resistant organisms. While conventional treatments rely heavily on antibiotic-loaded materials, bioactive glass S53P4 offers a dual-action alternative, combining bacteriostatic and bactericidal activity with bone regenerative potential. A systematic review and meta-analysis following PRISMA guidelines was conducted to evaluate the clinical efficacy and safety of S53P4 bioactive glass in osteomyelitis treatment. Twenty-eight studies published between 2000 and 2024, encompassing 1122 patients (mean age: 43.6 years), were included. Outcomes analyzed included infection eradication, recurrence, bone healing, functional recovery, and complications. The risk of bias was assessed using ROBINS-I for observational studies and the JBI checklist for case series. A meta-analysis of 10 studies reporting infection eradication at ≥ 12 months was performed using a random-effects model. The pooled infection eradication rate was 88.1% (95% CI: 85.4%-90.4%) with no significant heterogeneity (I2 = 0%). Studies reported consistent efficacy across chronic, diabetic foot, mastoid, and jaw osteomyelitis. S53P4 was effective against polymicrobial and multidrug-resistant infections, including Staphylococcus aureus and Pseudomonas aeruginosa. Healing outcomes were favorable, with high rates of bone integration and return to function. Complications were uncommon and primarily related to soft tissue coverage. Most patients received systemic antibiotics; no studies required local antibiotic-loaded materials alongside S53P4. Bioactive glass S53P4 is a safe and effective adjunct in osteomyelitis management, demonstrating high long-term infection control, robust bone regeneration, and a low complication profile. Its nonantibiotic antimicrobial mechanism makes it particularly suitable in settings of antimicrobial resistance. Future studies should assess its long-term durability and applications in high-risk infections.

Gelation Dynamics, Formation Mechanism, Functionalization, and 3D Bioprinting of Silk Fibroin Hydrogel Materials for Biomedical Applications

Silk fibroin (SF), derived from silk cocoon fibers (Bombyx mori), is a natural protein polymer known for its biocompatibility, biodegradability, and sustainability. The protein can be processed into various material formats suitable for a range of applications. Among these, SF hydrogels are useful in the biomedical field, such as tissue engineering, due to the tailorable structures and properties achievable through tuning the gelation process. Therefore, the focus of this contribution is to comprehensively review and understand the formation, gelation mechanism, dynamic control, and functionalization of SF hydrogels. Unlike previous reviews, this work delves into understanding the strategies and mechanisms for tuning the gelation dynamics of SF from molecular assembly and crystallization points of view. Further, this review presents functionalization pathways and practical examples, such as for the 3D printing of SF hydrogels, to illustrate how these strategies, mechanisms, and pathways can be implemented in a specific application scenario. With these insights, researchers can gain a deeper understanding of how to manipulate or control the gelation process and the types of functionalization to achieve specific properties and features. This knowledge would further facilitate the development and application of SF hydrogel materials in various fields.

Assessment of Novel Boron-doped Mesoporous Bioactive Glass Nanoparticles Loaded Alginate Hydrogel in Dogs

INTRODUCTION

Dentin regeneration is pivotal to preserve tooth vitality. This study aims to evaluate, histologically, the dentine regenerative potential of a novel injectable boron-doped, mesoporous, bioactive glass nanoparticle (BMBGNPs) loaded alginate hydrogel in dogs METHODS: The formulation and optimisation of the novel alginate/BMBG NPs (20 wt. %) loaded composite hydrogel were performed. Next, 66 teeth of 3 dogs were allocated into 3 groups (each including 22 teeth) according to post-operative follow-up period: group I: 2 weeks, group II: 4 weeks, and group III: 8 weeks. Each group was further subdivided according to pulpotomy filling material into two subgroups, with subgroup 1 (alginate/BMBGNPs (20 wt. %) loaded hydrogel) and subgroup 2 mineral trioxide aggregate (MTA). Pulp chambers were mechanically exposed through class V cavities. A complete pulpotomy was executed. The tested materials were positioned on the radicular pulp and finally covered with resin composite restorations. One dog was sacrificed after 2, 4, and 8 weeks. Teeth were prepared for histological evaluation assessing inflammatory cell response, pulp tissue organisation, and dentin bridge formation. The Mann-Whitney U test was employed to evaluate the scores of histological parameters between tested materials (P ≤ .05).

RESULTS

Alginate/BMBG NPs (20 wt. %) loaded hydrogel showed normal pulp configuration at 2 and 4 weeks, which was enhanced after 8 weeks (P ≤ .05). Moderate inflammatory reaction was noted at 2 weeks, which was improved after 4 and 8 weeks (P ≤ .05). MTA group demonstrated less favourable pulpal response and inflammatory reaction with a statistically significant difference across all observational periods (P ≤ .05). After 8 weeks all teeth in group 1 exhibited the thickest dentin bridge (P ≤ .05).

CONCLUSIONS

Alginate/BMBG NPs (20 wt. %) loaded hydrogel offers the promise of regenerating dentin and maintaining pulp vitality reaching the desired level as an alternative to MTA.

CLINICAL RELEVANCE

Alginate/BMBG NP loaded hydrogel is an alternative, reliable option for vital pulp therapy.

Exploring processing-structure-property relationships of chemically precipitated strontium silicate particles for medical applications

Bone regeneration in the presence of osteoporosis presents a significant challenge in dental and orthopedic surgery. To tackle this issue, researchers have developed strontium-containing biomaterials. However, preventing bacterial infection is also crucial for successful surgical treatment. In this study, we delved deep into the processing to tailor the composition and structure of new strontium silicates with unique properties to address this challenge. We used chemical precipitation to prepare various strontium silicate particles using varying ammonia concentrations and Sr/Si precursor ratios. The L929 cytotoxicity, differentiation of human mesenchymal stem cells (hMSCs), biological function of RAW 264.7 macrophages, and antibacterial activity against E. coli and S. aureus were evaluated. As a result, higher ammonia concentration led to the formation of SrSiO3 and Sr2SiO4 particles with smaller sizes and higher Sr/Si ratios. These particles exhibited increased antibacterial efficacy and radiopacity, promoting cell viability and osteogenic activity of hMSCs and modulating M1/M2 macrophage polarization. In conclusion, the developed strontium silicate demonstrated superior antibacterial activity, exceptional osteogenic properties, and clear visibility during procedures, making it a promising material for bone regeneration and osteoporosis treatment.

Bioadhesives and bioactive hydrogels for wound management

Delayed wound healing remains a major challenge in biomedical research, often leading to complications such as scarring, acute trauma, and chronic diseases. Effective wound management is crucial for enhancing treatment outcomes, preventing complications, and promoting tissue regeneration. In response to this need, a variety of polymeric biomaterials have been developed. A growing focus in the field involves the design of bioadhesives and bioactive materials, which offer promising solutions for wound management. Recent advances in materials engineering have led to the development of polymer biomaterials with excellent biocompatibility, strong adhesion to biological surfaces, and bioactive properties that support rapid wound closure and tissue repair. This review discusses the latest progress in the development and application of bioadhesives and bioactive hydrogels for wound management and tissue regeneration, highlighting potential directions for future biomaterial research.

Antibacterial and metalloproteinase-inhibited zinc-doped bioactive glass nanoparticles for enhancing dentin adhesion

OBJECTIVES

Novel zinc-doped bioactive glass nanoparticles (ZnBGNs) were designed for dental adhesive to enable multifunctional properties for dentin bonding durability.

METHODS

ZnBGNs were synthesized via the sol-gel template method and characterized via TEM, SEM and EDS. ZnBGNs were added from 2.5wt% to 10wt% to Adper™ Single Bond 2 adhesive (SB2). The effects of ZnBGNs on the degree of conversion, contact angle and antibacterial activity were measured. Endogenous matrix metalloproteinases (MMPs) activity, Young's modulus of the hybrid layer, microtensile bond strength and interfacial nanoleakage were investigated after 24 h and 3 months ageing in artificial saliva.

RESULTS

ZnBGNs exhibited good monodispersity, bioactivity activity and superior antimicrobial activity. Adding no >5 wt% ZnBGNs had no adverse effects on the degree of conversion and contact angle of the SB2 Control (p > 0.05). Incorporating ZnBGNs dramatically reduced the endogenous MMPs activity, facilitated remineralization and increased the Young's modulus of the hybrid layer after 3 months ageing (p < 0.05). Dentin bond strength had 44 % loss with increased nanoleakage after 3 months of ageing for SB2 Control. However, SB2+2.5 wt% ZnBGNs showed no loss in bond strength and the least degree of nanoleakage after 3 months ageing (p < 0.05).

CONCLUSIONS

Incorporating ZnBGNs into dental adhesive systems can provide antimicrobial, anti-metalloproteinase and remineralization microenvironments, which indicates a suitable strategy to prevent the degradation of hybrid layers.

CLINICAL SIGNIFICANCE

ZnBGNs with multifunctional properties will likely be used to prevent the degradation of hybrid layers, thereby extending the longevity of resin-dentin bonds.

Metal-organic framework (MOF)-bioactive glass (BG) systems for biomedical applications - A review

In recent years, metal-organic frameworks (MOFs) have emerged as promising materials for biomedical applications, owing to their superior chemical versatility, unique textural properties and enhanced mechanical properties. However, their fast and uncontrolled degradation, together with the reduced bioactivity have restricted their clinical potential. To overcome these limitations, MOFs can be synergistically combined with other materials, such as bioactive glasses (BGs), known for their bioactivity and therapeutic ion releasing capabilities. Besides comparing MOFs and BGs, this review aims to present the latest achievements of different MOFs/BGs materials, with a particular focus on their complementary and synergistic properties. Key findings show that combining MOFs and BGs enables the development of composite materials with superior physicochemical and biological properties. Moreover, by choosing appropriate processing techniques, BGs and MOFs can be fabricated as scaffolds or coatings with fast mineralization ability and high corrosion resistance. In addition, incorporation of MOFs/BGs in hydrogels improves mechanical stability, bioactivity and antibacterial properties, while maintaining biocompatibility. The mechanisms behind the antibacterial properties, likely coming from the release of metal ions and organic ligands, are also discussed. Overall, this review highlights the current research directions and emerging trends in the synergistic use of MOFs and BGs for biomedical applications, which represents a novel strategy for developing a new family of advanced therapeutic materials.

Photothermal-enhanced silver nanocluster bioactive glass hydrogels for synergistic antimicrobial and promote wound healing

Antibacterial hydrogels are promising for combating infections and promoting wound healing. Nevertheless, excessive antibiotics induce resistance, and high metal ion levels cause cytotoxicity, complicating healing. Here, we introduce a hydrogel incorporating polydopamine-coated bioactive glass (BGs@PDA) on reduced graphene oxide (rGO) with photothermal therapy (PTT) and silver nanoclusters (AgNCs) for synergistic antibacterial treatment. This design enables rapid bacterial eradication and controlled release. Near-infrared-assisted heating provides noninvasive, targeted hyperthermia, killing bacteria quickly. Post-PTT addition of low-dose AgNCs reduces toxicity while enhancing antimicrobial efficacy and biocompatibility. BGs@PDA-loaded rGO prevents sedimentation, improves photothermal conversion and conductivity, and stabilizes the hydrogel structure. Constructed from chitosan and hydroxyethyl cellulose, the hydrogel is cross-linked by PDA and rGO, enhancing mechanical strength, adhesion, self-healing, free radical scavenging, and continuous wound exudate absorption. PDA encapsulation facilitates BGs degradation, improving the wound microenvironment. In vivo studies confirm accelerated healing and potent synergistic antibacterial effects, indicating its potential as a low-dose, antibiotic-free alternative for clinical wound infection management.

A Bioprinted Hydrogel Patch With Bioactive Glass: A New Frontier in Chronic Wound Healing

A wound, defined as a disruption in the continuity of the skin, is among the most common issues in the population and poses a significant burden on healthcare systems and economies worldwide. Despite the countless medical devices currently available to promote wound repair and skin regeneration, there is a growing demand for new skin devices that incorporate innovative biomaterials and advanced technologies. Bioglasses are biocompatible and bioactive materials capable of interacting with biological tissues. Due to their ability to promote fibroblast proliferation, angiogenesis, collagen production, and evade antibacterial activity, they have been suggested as key players in the skin regeneration process. Since their initial introduction, various compositions have been proposed depending on the clinical goal to be achieved. Recently, a novel bioglass composition named Bio_MS was found to exhibit significant bone regenerative potential. Given its peculiar composition characterized by strontium and magnesium, Bio_MS could also play a role in skin healing. In the present work, an innovative patch was designed by combining the attractive characteristics of Bio_MS with bioprinting technology. The regenerative potential of the Bio_MS patch was tested in an ex vivo cutaneous model using human skin in which an experimental wound was induced by sodium dodecyl sulfate incubation. After injury, the Bio_MS patch was able to restore skin architecture and enhance the epidermal barrier function. Additionally, the Bio_MS patch demonstrated therapeutic effects in both the epidermis and dermis, making it suitable not only for superficial lesions but also for deep wounds.

Bioactive glass-polymer nanocomposites: a comprehensive review on unveiling their biomedical applications

Most natural and synthetic polymers are promising materials for biomedical applications because of their biocompatibility, abundant availability, and biodegradability. Their properties can be tailored according to the intended application by fabricating composites with other polymers or ceramics. The incorporation of ceramic nanoparticles such as bioactive glass (BG) and hydroxyapatite aids in the improvement of mechanical and biological characteristics and alters the degradation kinetics of polymers. BG can be used in the form of nanoparticles, nanofibers, scaffolds, pastes, hydrogels, or coatings and is significantly employed in different applications. This biomaterial is highly preferred because of its excellent biocompatibility, bone-stimulating activity, and favourable mechanical and degradation characteristics. Different compositions of nano BG are incorporated into the polymer system and studied for positive results such as enhanced bioactivity, better cell adherence, and proliferation rate. This review summarizes the fabrication and the progress of natural/synthetic polymer-nano BG systems for biomedical applications such as drug delivery, wound healing, and tissue engineering. The challenges and the future perspectives of the composite system are also addressed.

Advancing Periodontal Care: Development of a Novel Collagen-Chitosan-Bioglass Scaffold as a Substitute for Autologous Soft Tissue Grafts

Introduction Modern dentistry prioritizes aesthetic outcomes, making root coverage for gingival recession a key focus. Various approaches, including autologous grafts, address this issue, yet no substitute matches the properties of autogenous connective tissue grafts. The innovative collagen-chitosan-bioglass scaffold presents a promising solution, surpassing the limitations of the traditional methods. This scaffold blends the advantages of collagen with chitosan's antibacterial and regenerative properties, enhanced by bioglass, which promotes tissue healing through angiogenesis. It was evaluated for its physicochemical characteristics, as well as antioxidative and anti-inflammatory properties, making it a promising solution for soft tissue management in dentistry. Materials and methods Chitosan, collagen, and bioglass were combined into a scaffold through the lyophilization process (freeze-drying). Chitosan was sourced from shrimp, collagen from bovine, and the bioglass 1% comprised 58% tetra-ethyl ortho silicate, 33% calcium silicate, and phosphorous pentoxide. After the scaffold was created, it was subjected to physicochemical characterization via scanning electron microscopic and infrared spectroscopic analysis. Its anti-inflammatory and antioxidant properties were evaluated using DPPH (2,2-diphenyl -1-picrylhydrazyl) assay and by measuring the scaffold's radical scavenging activity. Results This study employed infrared spectroscopy and scanning electron microscopy techniques to analyze the sample components and their morphology. The infrared (attenuated total reflection) analysis revealed various elements confirming the presence of all the biomaterials required to fabricate the scaffold. Scanning electron microscope imaging displayed a folded-like morphology with a porous structure. The protein denaturation inhibition increased from 25% at 50 μg of scaffold weight to 45% at 200 μg of scaffold weight. Similarly, the antioxidant activity increased, with values rising from 23% at 50μg to 35% at 200μg of scaffold weight. Conclusion The fabricated collagen-chitosan-bioglass scaffold demonstrates promising antioxidant and anti-inflammatory properties. These findings suggest that this scaffold holds significant potential as a viable substitute for soft tissue augmentation.

45S5 Bioactive Glass-Ointment Positively Effects on Wound Healing in Rats by Regulating TNFα, Il-10, VEGF, and TGFβ

AIM

This study aimed to investigate the effects of 45S5 bioactive glass-ointment (BG) on cutaneous wound healing in rats at the molecular, biochemical, and histopathological levels.

MATERIALS AND METHODS

Thirty-two rats were divided into four groups (n = 8): Control, Sham, BG, and DEX (Dexpanthenol). While no wound treatment was applied to the CONTROL, a wound model was created in the Sham, and no treatment was applied. A wound model was created for other groups, and BG and DEX were applied locally for 21 days. During the 21-day experiment period, feed and water consumption and weight changes were observed. Wound areas were calculated on days 0, 3, 7, 4, and 21. Following treatment, the rats were euthanized and tissues from the wound area and blood samples were collected. While the expression levels of tumor necrosis factor-alpha (TNFα), Interleukin 6 (IL6), Interleukin 10 (IL10), transforming growth factor-beta (TGFβ), and vascular endothelial growth factor (VEGF) genes were determined by qPCR, the levels of TNFα, IL6, and IL10 proteins were measured by ELISA.

RESULTS

It was observed that the BG group showed anti-inflammatory activity by suppressing TNFα levels and stimulating IL-10. In addition, it was determined that BG increased fibroblast activity and vascularization.

CONCLUSION

Current findings showed that topical application of BG has anti-inflammatory effects, while also accelerating healing by increasing vascularity and making positive contributions to tissue healing.

Temperature-responsive bioactive glass/polymer hybrids allow for tailoring of ion release

Intelligent biomaterials react to their surrounding conditions, and hybrid materials are acknowledged for their remarkable customizability, achieved through the meticulous control of nanoscale interactions between organic and inorganic phases. Bioactive glasses (BG) are used clinically to regenerate bone due to their degradability, ion release, and capacity to stimulate the formation of new body tissue. In our study, we developed a core-shell hybrid system using sol-gel derived BG nano particles as the core and poly (N-isopropyl acrylamide) (PNIPAM) as the shell. This approach aims to combine the therapeutic ion release of BG with the temperature-responsive properties of PNIPAM. Our size analysis by dynamic light scattering at varying temperatures shows the formation of BG aggregates driven by the coil-to-globule transition of PNIPAM on the BG surface. This transition also affected the ion release from the core-shell system through an increase in ion transport through the porous hybrid network. Our study therefore illustrates the ability to adjust the dissolution properties of the core-shell system via surrounding temperature and, thus, control the release of Ca ions from the BG.

Advancements in Biomedical Applications of Calcium Phosphate Glass and Glass-Based Devices-A Review

Calcium phosphate (CaP) glass has recently gained popularity as a promising material for a wide range of biomedical applications. Recent developments have seen CaP glasses moving from a passive implant material to an active degradable material, particularly as a major constituent of bioresorbable photonic devices. This holds great promise in advanced biomedical applications, since the main constituents of CaP glasses are present in the human body. In this review, the progressive advancements in the biomedical applications of calcium phosphate glass-based devices over the past 50 years are discussed. An overview of their role as reinforcing agents and the studies on doping their matrices for ion releasing and drug and gene delivery are reviewed. Recent applications of CaP glass and fibers in soft-tissue engineering and their potential for optical quality bioresorbable devices are then discussed along with the current challenges and potential future directions, emphasizing the promising role of CaP glass in the next generation of biomaterials. Considering their progress and potential in performing several biomedical functionalities over time, CaP glass-based devices hold promise for becoming enabling tools as an implantable, bioresorbable, multifunctional class of devices in future biomedicine.

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.

Extracellular and intracellular effects of bioactive glass nanoparticles on osteogenic differentiation of bone marrow mesenchymal stem cells and bone regeneration in zebrafish osteoporosis model

Bioactive glass nanoparticles (BGNs) are well-recognized multifunctional biomaterials for bone tissue regeneration due to their capability to stimulate various cellular processes through released biologically active ions. Understanding the correlation between BGN composition and cellular responses is key to developing clinically usable BGN-based medical devices. This study investigated the influence of CaO content of binary SiO2-CaO BGNs (CaO ranging from 0 to 10 mol%) on osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and in vivo bone regeneration in zebrafish osteoporosis model. The results showed that BGNs could promote osteogenic differentiation of rBMSCs by indirectly releasing active ions or directly interacting with rBMSCs by internalization. In both situations, BGNs of a higher CaO content could promote the osteogenic differentiation of rBMSCs to a greater extent. The internalized BGNs could activate the transcription factors RUNX2 and OSX, leading to the expression of osteogenesis-related genes. The results in the zebrafish osteoporosis model indicated that the presence of BGNs of higher CaO contents could enhance bone regeneration and rescue dexamethasone-induced osteoporosis to a greater extent. These findings demonstrate that BGNs can stimulate osteogenic differentiation of rBMSCs by releasing active ions or internalization. A higher CaO content facilitates osteogenesis and bone regeneration of zebrafish as well as relieving dexamethasone-induced osteoporosis. The zebrafish osteoporosis model can be a potent tool for evaluating the in vivo bone regeneration effects of bioactive materials. STATEMENT OF SIGNIFICANCE: Bioactive glass nanoparticles (BGNs) are increasingly used as fillers of nanocomposites or as delivery platforms of active ions to regenerate bone tissue. Various studies have shown that BGNs can enhance osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by releasing active ions. However, the correlation between BGN composition and cellular responses and in vivo bone regeneration effect has still not been well investigated. Establishment of a suitable in vivo animal model for investigating this correlation is also challenging. The present study reports the influence of CaO content in binary SiO2-CaO BGNs on osteogenic differentiation of BMSCs extracellularly and intracellularly. This study also demonstrates the suitability of zebrafish osteoporosis model to investigate in vivo bone regeneration effect of BGNs.

The Impact of 45S5-Bioactive Glass on Synovial Cells in Knee Osteoarthritis-An In Vitro Study

Synovial inflammation in osteoarthritis (OA) is characterized by the release of cartilage-degrading enzymes and inflammatory cytokines. 45S5-bioactive glass (45S5-BG) can modulate inflammation processes; however, its influence on OA-associated inflammation has hardly been investigated. In this study, the effects of 45S5-BG on the release of cartilage-degrading metalloproteinases and cytokines from synovial membrane cells (SM) isolated from patients with knee OA was assessed in vitro. SM were cultivated as SM monocultures in the presence or absence of 45S5-BG. On day 1 (d1) and d7 (d7), the concentrations of Matrix Metalloproteinases (MMPs) and cytokines were assessed. In 45S5-BG-treated SM cultures, MMP9 concentration was significantly reduced at d1 and d7, whilst MMP13 was significantly increased at d7. Concentrations of interleukin (IL)-1B and C-C motif chemokine ligand 2 (CCL2) in 45S5-BG-treated SM cultures were significantly increased at both time points, as were interferon gamma (IFNG) and IL-6 at d7. Our data show an effect of 45S5-BG on SM activity, which was not clearly protective, anti-inflammatory, or pro-inflammatory. The influence of 45S5-BG on MMP release was more suggestive of a cartilage protective effect, but 45S5-BG also increased the release of pro-inflammatory cytokines. Further studies are needed to analyze the effect of BGs on OA inflammation, including the anti-inflammatory modification of BG compositions.

Opportunities for Bioactive Glass in Gastrointestinal Conditions: A Review of Production Methodologies, Morphology, Composition, and Performance

Bioactive glasses (BGs) are widely used in orthopedic and dental applications for their ability to stimulate endogenous bone formation and regeneration. BG applications more recently broadened to include soft tissue conditions, based on their ability to stimulate angiogenesis, soft tissue regeneration, and wound healing. Sol-gel synthesis has helped facilitate this expansion, allowing formulators to tailor the morphological characteristics of the BG matrix. The effectiveness of BGs in skin wound healing is viewed as a gateway for their use as both a therapeutic and drug delivery platform in other soft tissue applications, notably gastrointestinal (GI) applications, which form the focus of this review. Recent changes in international guidelines for GI conditions shifted clinical objectives from symptom management to mucosal wound healing. The additional scrutiny of proton pump inhibitor (PPI) safety, increasing burden of disease, and financial costs associated with gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), and inflammatory bowel disease (IBD) open new clinical possibilities for BG. This narrative literature review intersects materials engineering, formulation science, and clinical practice, setting it apart from prior literature. Broadly, current evidence for BG applications in GI conditions is sparse and under-developed, which this review directly addresses. It explores and synthesizes evidence that supports the potential use of sol-gel-derived BG for the efficacious treatment of soft tissue applications, with specific reference to GI conditions. An overview with comparative analysis of current BG synthesis techniques and associated challenges is presented, and influences of composition, biologically active ions, and morphological characteristics in soft tissue applications are explored. To contextualize this, sol-gel-derived BGs are proposed as a dual, tailorable therapeutic and drug delivery platform for upper and lower GI conditions. Future directions for this largely untapped area of translational research are also proposed, based on extant literature.

Silver-doped bioactive glass fibres as a potential treatment for wound-associated bacterial biofilms

Chronic wounds are a drain on global health services and remain a major area of unmet clinical need. Chronic wounds are characterised by a stable and stubborn bacterial biofilm which hinders innate immune response and delays or prevents wound healing. Bioactive glass (BG) fibres offer a promising novel treatment for chronic wounds by targeting the wound-associated biofilm. In this study, the antimicrobial properties of silver-doped BG fibres were tested against Pseudomonas aeruginosa biofilms, which are commonly found in chronic wound infections. Results showed that BG fibres doped with silver resulted in a 5log10 reduction in biofilm formation whereas silver-free fibres only reduced formation by log10, therefore silver-doped fibres possess stronger antimicrobial effects. Moreover, there appeared to be a synergistic effect between the fibres and the silver as the application of the silver-doped fibres placed directly in contact with the forming biofilm resulted in a higher reduction in biofilm formation compared to treatments either: using the dissolution ions, using BG powder, or when the fibres were placed in an insert above the biofilm, inhibiting physical contact, instead. This suggests that the physical properties of the fibres, as well as silver, influence biofilm formation. Finally, results demonstrated that silver chloride, which is not antimicrobial, forms and the concentrations of antimicrobial silver species, namely silver ions and nanoparticles, reduce over time when fibres are soaked in cell culture media, which partially explains why the silver-doped dissolution ions contained lower antimicrobial activity compared to the fibres. As silver chloride is more likely to form with increased temperature and time, the antimicrobial activity of silver-containing dissolution ions is highly dependent on the length of ageing and storage conditions. Many studies investigate the antimicrobial and cytotoxic properties of biomaterials through their dissolution products. However, instability of antimicrobial silver species due to silver chloride formation and its effect on antimicrobial properties of silver-based biomaterials has not been reported before and could influence past and future dissolution-based assays as results showed that the antimicrobial activity of silver-based dissolution ions can vary greatly depending on post processing steps and can therefore produce misleading data.

Cell-loaded genipin cross-linked collagen/gelatin skin substitute adorned with zinc-doped bioactive glass-ceramic for cutaneous wound regeneration

An optimal tissue-engineered dermal substitute should possess biocompatibility and cell adhesion conduction to facilitate fibroblast and keratinocyte infiltration and proliferation, as well as angiogenesis potential to escalate wound healing. Zinc was doped to bioactive glass-ceramic (Zn-BGC) to promote biocompatibility and angiogenesis properties. Zn-BGC was then incorporated into a collagen (Col) and gelatin (Gel) porous scaffold. The bioactive porous bionanocomposite exhibited biocompatibility along with improved cell attachment and proliferation. Scaffolds including Col-Gel/Zn-BGC with or without mouse embryonic fibroblasts were applied on full-thickness skin wounds on the BALB/c mice to assess their wound healing potential in vivo. The results indicated that the biodegradation rate of the Col-Gel/Zn-BGC nanocomposites was comparable to the rate of skin tissue regeneration in vivo. Macroscopic wound healing results showed that Col-Gel/Zn-BGC loaded with mouse embryonic fibroblast possesses the smallest wound size, indicating the fastest healing process. Histopathological evaluations displayed that the optimal wound regeneration was observed in Col-Gel/Zn-BGC nanocomposites loaded with mouse embryonic fibroblasts indicated by epithelialization and angiogenesis; besides the number of fibroblasts and hair follicles was increased. The bioactive nanocomposite scaffold of Col-Gel containing Zn-BGC nanoparticles loaded with mouse embryonic fibroblasts can be employed as a desirable skin substitute to ameliorate cutaneous wound regeneration.

Wound healing performance of electrospun PVA/70S30C bioactive glass/Ag nanoparticles mats decorated with curcumin: In vitro and in vivo investigations

Biocompatible fibrous scaffold containing polyvinyl alcohol (PVA), 70S30C bioactive glass (BG), silver (Ag) nanoparticles and curcumin (Cur) was fabricated through electrospinning method. Scanning electron microscope (SEM) and Field emission scanning electron microscopy (FESEM) were employed to investigate the morphological characteristics of the scaffolds. In addition, biodegradability, hydrophilicity, and contact angle were studied as criteria for evaluating physical properties of the scaffolds. Tensile strength was reported to be 0.971 ± 0.093 MPa. Also, the viability of fibroblasts after 7 days of cell culture was 93.58 ± 1.36 %. The antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria was illustrated using inhibition zones of 13.12 ± 0.69 and 14.21 ± 1.37 mm, respectively. Histological results revealed that tissue regeneration after 14 days of surgery was much higher for the dressing group compared to the blank group. According to the obtained results, the authors introduce the PVA-BG-Ag-Cur scaffold as a promising candidate for skin tissue engineering applications.

Cu-HKUST-1 and Hydroxyapatite-The Interface of Two Worlds toward the Design of Functional Materials Dedicated to Bone Tissue Regeneration

A novel composite based on biocompatible hydroxyapatite (HA) nanoparticles and Cu-HKUST-1 (Cu-HKUST-1@HA) has been prepared following a layer-by-layer strategy. Cu-HKUST-1 was carefully selected from a group of four Cu-based metal-organic frameworks as the material with the most promising antimicrobial activity. The formation of a colloidal Cu-HKUST-1 layer on HA nanoparticles was confirmed by various techniques, e.g., infrared spectroscopy, powder X-ray diffraction, N2 sorption, transmission electron microscopy imaging, electron paramagnetic resonance, and X-ray absorption spectroscopy. Importantly, such a Cu-HKUST-1 layer significantly improved the nanomechanical properties of the composite, with Young's modulus equal to that of human cortical bone (13.76 GPa). At the same time, Cu-HKUST-1@HA has maintained the negative zeta potential (-16.3 mV in pH 7.4) and revealed biocompatibility toward human dermal fibroblasts up to a concentration of 1000 μg/mL, without inducing ex vivo hemolysis. Chemical stability studies of the composite over 21 days in a buffer-simulated physiological fluid allowed a detailed understanding of the transformations that the Cu-HKUST-1@HA undergoes over time. Finally, it has been confirmed that the Cu-HKUST-1 layer provides antibacterial properties to HA, and the synergism reached in this way makes it promising for bone tissue regeneration.

Advanced Bioactive Glasses: The Newest Achievements and Breakthroughs in the Area

Bioactive glasses (BGs) are especially useful materials in soft and bone tissue engineering and even in dentistry. They can be the solution to many medical problems, and they have a huge role in the healing processes of bone fractures. Interestingly, they can also promote skin regeneration and wound healing. Bioactive glasses are able to attach to the bone tissues and form an apatite layer which further initiates the biomineralization process. The formed intermediate apatite layer makes a connection between the hard tissue and the bioactive glass material which results in faster healing without any complications or side effects. This review paper summarizes the most recent advancement in the preparation of diverse types of BGs, such as silicate-, borate- and phosphate-based bioactive glasses. We discuss their physical, chemical, and mechanical properties detailing how they affect their biological performances. In order to get a deeper insight into the state-of-the-art in this area, we also consider their medical applications, such as bone regeneration, wound care, and dental/bone implant coatings.

Cobalt-containing borate bioactive glass fibers for treatment of diabetic wound

Impaired angiogenesis is one of the predominant reasons for non-healing diabetic wounds. Cobalt is well known for its capacity to induce angiogenesis by stabilizing hypoxia-inducible factor-1α (HIF-1α) and subsequently inducing the production of vascular endothelial growth factor (VEGF). In this study, Co-containing borate bioactive glasses and their derived fibers were fabricated by partially replacing CaO in 1393B3 borate glass with CoO. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) analyses were performed to characterize the effect of Co incorporation on the glass structure, and the results showed that the substitution promoted the transformation of [BO3] into [BO4] units, which endow the glass with higher chemical durability and lower reaction rate with the simulated body fluid (SBF), thereby achieving sustained and controlled Co2+ ion release. In vitro biological assays were performed to assess the angiogenic potential of the Co-containing borate glass fibers. It was found that the released Co2+ ion significantly enhanced the proliferation, migration and tube formation of the Human Umbilical Vein Endothelial Cells (HUVECs) by upregulating the expression of angiogenesis-related proteins such as HIF-1α and VEGF. Finally. In vivo results demonstrated that the Co-containing fibers accelerated full-thickness skin wound healing in streptozotocin (STZ)-induced diabetic rat model by promoting angiogenesis and re-epithelialization.

In-vivo evaluations of bone regenerative potential of two novel bioactive glasses

Due to the aging of population, materials able to repair damaged tissues are needed. Among others, bioactive glasses (BGs) have attracted a lot of interest due to their outstanding properties both for hard and soft tissues. Here, for the first time, two new BGs, which gave very promising results in preliminary in vitro-tests, were implanted in animals in order to evaluate their regenerative potential. The new BGs, named BGMS10 and Bio_MS and containing specific therapeutic ions, were produced in granules and implanted in rabbits' femurs for up to 60 days, to test their biocompatibility and osteoconduction. Additionally, granules of 45S5 Bioglass® were employed and used as a standard reference for comparison. The results showed that, after 30 days, the two novel BGs and 45S5 displayed a similar behavior, in terms of bone amount, thickness of new bone trabeculae and affinity index. On the contrary, after 60 days, 45S5 granules were mainly surrounded by wide and scattered bone trabeculae, separated by large amounts of soft tissue, while in BGMS10 and Bio_MS the trabeculae were thin and uniformly distributed around the BG granules. This latter scenario could be considered as more advantageous, since the features of the two novel BG granules allowed for the neo-formation of a uniformly distributed bony trabeculae, predictive of more favorable mechanical behavior, compared to the less uniform coarse trabeculae, separated by large areas of soft tissue in 45S5 granules. Thus, BGMS10 and Bio_MS could be considered suitable products for tissue regeneration in the orthopedic and dental fields.

Unusual Surface Coagulation Activation Patterns of Crystalline and Amorphous Silicate-Based Biominerals

Activation of coagulation cascades, especially FX and prothrombin, prevents blood loss and reduces mortality from hemorrhagic shock. Inorganic salts are efficient but cannot stop bleeding completely in hemorrhagic events, and rebleeding carries a significant mortality risk. The coagulation mechanism of biominerals has been oversimplified in the past two decades, limiting the creation of novel hemostats. Herein, at the interface, the affinity of proteins, the protease activity, fibrinolysis, hydration shell, and dynamic microenvironment are monitored at the protein level. Proteomic analysis reveals that fibrinogen and antithrombin III's affinity for kaolin's interface causes a weak thrombus and rebleeding during hemostasis. Inspiringly, amorphous bioactive glass (BG) with a transient-dynamic ion microenvironment breaches the hydration layer barrier and selectively and slightly captures procoagulant components of kiniogen-1, plasma kallikrein, FXII, and FXI proteins on its interface, concurrently generating a continuous biocatalytic interface to rapidly activate both intrinsic and extrinsic coagulation pathways. Thus, prothrombin complexes are successfully hydrolyzed to thrombin without platelet membrane involvement, speeding production of high-strength clots. This study investigates how the interface of inorganic salts assists in coagulation cascades from a more comprehensive micro-perspective that may help elucidate the clinical application issues of kaolin-gauze and pave the way to new materials for managing hemorrhage.

Nanofibrous Polycaprolactone Membrane with Bioactive Glass and Atorvastatin for Wound Healing: Preparation and Characterization

Skin wound healing is one of the most challenging processes for skin reconstruction, especially after severe injuries. In our study, nanofiber membranes were prepared for wound healing using an electrospinning process, where the prepared nanofibers were made of different weight ratios of polycaprolactone and bioactive glass that can induce the growth of new tissue. The membranes showed smooth and uniform nanofibers with an average diameter of 118 nm. FTIR and XRD results indicated no chemical interactions of polycaprolactone and bioactive glass and an increase in polycaprolactone crystallinity by the incorporation of bioactive glass nanoparticles. Nanofibers containing 5% w/w of bioactive glass were selected to be loaded with atorvastatin, considering their best mechanical properties compared to the other prepared nanofibers (3, 10, and 20% w/w bioactive glass). Atorvastatin can speed up the tissue healing process, and it was loaded into the selected nanofibers using a dip-coating technique with ethyl cellulose as a coating polymer. The study of the in vitro drug release found that atorvastatin-loaded nanofibers with a 10% coating polymer revealed gradual drug release compared to the non-coated nanofibers and nanofibers coated with 5% ethyl cellulose. Integration of atorvastatin and bioactive glass with polycaprolactone nanofibers showed superior wound closure results in the human skin fibroblast cell line. The results from this study highlight the ability of polycaprolactone-bioactive glass-based fibers loaded with atorvastatin to stimulate skin wound healing.

Evaluation of Psoas Muscle Atrophy and the Degree of Fat Infiltration After Unilateral Hip Arthroplasty

OBJECTIVE

Atrophy of the muscles around the hip and thigh has been reported in patients with hip osteoarthritis (OA). Total hip arthroplasty (THA) reduces pain and improves quality of life and activity levels. Muscle strength of the hip and thigh also improves after THA. This study aimed to determine whether there is significant psoas muscle atrophy and to evaluate the degree of fat infiltration after unilateral hip arthroplasty.

SUBJECT AND METHODS

Patients who underwent unilateral total hip arthroplasty for primary hip osteoarthritis and who had lumbar vertebra magnetic resonance imaging (MRI) for any reason in the one-year preoperative and postoperative period were evaluated retrospectively. The degree of fat infiltration was also graded visually based on a modified Goutallier rating system.

RESULTS

The study was conducted with a total of 58 patients aged between 38 and 75, including 15 males and 43 females. Compared to the preoperative psoas muscle area values on the operated sides of the patients participating in the study, the decrease in the postoperative psoas muscle area was found to be statistically significant (p:0.000; p<0.05). Furthermore, the decrease in psoas muscle area on the non-operated side of the patients was also statistically significant (p:0.000; p<0.05). There was also a positive correlation between preoperative and postoperative psoas muscle areas (p:0.000; p<0.05).

CONCLUSION

Early identification of psoas muscle mass reduction may allow for a more proactive psoas strength improvement program to improve post-operative function and mobility.

Multifunctional Oxidized Dextran Cross-Linked Alkylated Chitosan/Drug-Loaded and Silver-Doped Mesoporous Bioactive Glass Cryogel for Hemostasis of Noncompressible Wounds

Noncompressible wounds resulting from accidents and gunshots are typically associated with excessive bleeding, slow wound healing, and bacterial infection. Shape-memory cryogel presents great potential in controlling the hemorrhaging of noncompressible wounds. In this research, a shape-memory cryogel was prepared using a Schiff base reaction between alkylated chitosan (AC) and oxidized dextran (ODex) and then incorporated with a drug-laden and silver-doped mesoporous bioactive glass (MBG). Hydrophobic alkyl chains enhanced the hemostatic and antimicrobial efficiency of the chitosan, forming blood clots in the anticoagulated condition, and expanding the application scenarios of chitosan-based hemostats. The silver-doped MBG activated the endogenous coagulation pathway by releasing Ca²⁺ and prevented infection through the release of Ag⁺. In addition, the proangiogenic desferrioxamine (DFO) in the mesopores of the MBG was released gradually to promote wound healing. We demonstrated that AC/ODex/Ag-MBG DFO(AOM) cryogels exhibited excellent blood absorption capability, facilitating rapid shape recovery. It provided a higher hemostatic capacity in normal and heparin-treated rat-liver perforation-wound models than gelatin sponges and gauze. The AOM gels simultaneously promoted infiltration, angiogenesis, and tissue integration of liver parenchymal cells. Furthermore, the composite cryogel exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Thus, AOM gels show great promise for clinical translation in treating lethal, noncompressible bleeding and the promotion of wound healing.

Nanoscale borosilicate bioactive glass for regenerative therapy of full-thickness skin defects in rabbit animal model

Bioactive glass (BG) occupies a significant position in the field of hard and soft tissue regeneration. Different processing techniques and formulas have been introduced to expand their regenerative, angiogenic, and antibacterial properties. In the present study, a new formula of bborosilicate bioactive glass nanofibers was prepared and tested for its wound-healing efficacy in a rabbit animal model. The glass formula ((1-2) mol% of B₂O₃ (68-69) mol% of SiO2, and (29-30) mol% of CaO) was prepared primarily by the sol-gel technique followed by the electrospinning technique. The material was characterized for its ultrastructure using scanning electron microscopy, chemical composition using FTIR, and its dynamic in vitro biodegradability using ICP-AES. Twelve rabbits were subjected to surgical induction of full-thickness skin defects using a 1 cm² custom-made stainlessteel skin punch. The bioactive glass nanofibers were used as a grafting material in 6 experimental rabbits, while the defects in the remaining rabbits were considered as the negative control samples. All defects were assessed clinically for the decrease in wound size and clinical signs of healing and histologically for angiogenesis, collagen density, inflammatory response, cell recruitment, epithelial lining, and appendages at 1,2 and 3 weeks following the intervention. Structural analysis of the glass fibers confirmed their nano-size which ranged from 150 to 700 nm. Moreover, the chemical analysis confirmed the presence of SiO₂ and B₂O₃ groups within the structure of the nanofibers. Additionally, dynamic biodegradation analysis confirmed the rapid degradation of the material starting from the first 24 h and rapid leaching of calcium, silicon, and boron ions confirming its bioactivity. The wound healing study of the nanofibrous scaffold confirmed its ability to accelerate wound healing and the closure rate in healthy rabbits. Histological analysis of the defects confirmed the angiogenic, regenerative and antibacterial ability of the material throughout the study period. The results unveil the powerful therapeutic properties of the formed nanofibers and open a new gate for more experimental and clinical applications.

Trends and perspectives on the commercialization of bioactive glasses

At least 25 bioactive glass (BG) medical devices have been approved for clinical use by global regulatory agencies. Diverse applications include monolithic implants, bone void fillers, dentin hypersensitivity agents, wound dressing, and cancer therapeutics. The morphology and delivery systems of bioactive glasses have evolved dramatically since the first devices based on 45S5 Bioglass®. The particle size of these devices has generally decreased with the evolution of bioactive glass technology but primarily lies in the micron size range. Morphologies have progressed from glass monoliths to granules, putties, and cements, allowing medical professionals greater flexibility and control. Compositions of these commercial materials have primarily relied on silicate-based systems with varying concentrations of sodium, calcium, and phosphorus. Furthermore, therapeutic ions have been investigated and show promise for greater control of biological stimulation of genetic processes and increased bioactivity. Some commercial products have exploited the borate and phosphate-based compositions for soft tissue repair/regeneration. Mesoporous BGs also promise anticancer therapies due to their ability to deliver drugs in combination with radiotherapy, photothermal therapy, and magnetic hyperthermia. The objective of this article is to critically discuss all clinically approved bioactive glass products. Understanding essential regulatory standards and rules for production is presented through a review of the commercialization process. The future of bioactive glasses, their promising applications, and the challenges are outlined. STATEMENT OF SIGNIFICANCE: Bioactive glasses have evolved into a wide range of products used to treat various medical conditions. They are non-equilibrium, non-crystalline materials that have been designed to induce specific biological activity. They can bond to bone and soft tissues and contribute to their regeneration. They are promising in combating pathogens and malignancies by delivering drugs, inorganic therapeutic ions, and heat for magnetic-induced hyperthermia or laser-induced phototherapy. This review addresses each bioactive glass product approved by regulatory agencies for clinical use. A review of the commercialization process is also provided with insight into critical regulatory standards and guidelines for manufacturing. Finally, a critical evaluation of the future of bioactive glass development, applications, and challenges are discussed.

Cobalt containing glass fibres and their synergistic effect on the HIF-1 pathway for wound healing applications

Introduction and Methods: Chronic wounds are a major healthcare problem, but their healing may be improved by developing biomaterials which can stimulate angiogenesis, e.g. by activating the Hypoxia Inducible Factor (HIF) pathway. Here, novel glass fibres were produced by laser spinning. The hypothesis was that silicate glass fibres that deliver cobalt ions will activate the HIF pathway and promote the expression of angiogenic genes. The glass composition was designed to biodegrade and release ions, but not form a hydroxyapatite layer in body fluid.

Results and Discussion: Dissolution studies demonstrated that hydroxyapatite did not form. When keratinocyte cells were exposed to conditioned media from the cobalt-containing glass fibres, significantly higher amounts of HIF-1α and Vascular Endothelial Growth Factor (VEGF) were measured compared to when the cells were exposed to media with equivalent amounts of cobalt chloride. This was attributed to a synergistic effect of the combination of cobalt and other therapeutic ions released from the glass. The effect was also much greater than the sum of HIF-1α and VEGF expression when the cells were cultured with cobalt ions and with dissolution products from the Co-free glass, and was proven to not be due to a rise in pH. The ability of the glass fibres to activate the HIF-1 pathway and promote VEGF expression shows the potential for their use in chronic wound dressings.

Bioactive glass-elicited stem cell-derived extracellular vesicles regulate M2 macrophage polarization and angiogenesis to improve tendon regeneration and functional recovery

Effective countermeasures for tendon injury remains unsatisfactory. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs)-based therapy via regulation of Mφ-mediated angiogenesis has emerged as a promising strategy for tissue regeneration. Still, approaches to tailor the functions of EVs to treat tendon injuries have been limited. We reported a novel strategy by applying MSC-EVs boosted with bioactive glasses (BG). BG-elicited EVs (EV_B) showed up-regulation of medicinal miRNAs, including miR-199b-3p and miR-125a-5p, which play a pivotal role in M2 Mφ-mediated angiogenesis. EV_B accelerated angiogenesis via the reprogrammed anti-inflammatory M2 Mφs compared with naïve MSC-EVs (EV_N). In rodent Achilles tendon rupture model, EV_B local administration activated anti-inflammatory responses via M2 polarization and led to a spatial correlation between M2 Mφs and newly formed blood vessels. Our results showed that EV_B outperformed EV_N in promoting tenogenesis and in reducing detrimental morphological changes without causing heterotopic ossification. Biomechanical test revealed that EV_B significantly improved ultimate load, stiffness, and tensile modulus of the repaired tendon, along with a positive correlation between M2/M1 ratio and biomechanical properties. On the basis of the boosted nature to reprogram regenerative microenvironment, EV_B holds considerable potential to be developed as a next-generation therapeutic modality for enhancing functional regeneration to achieve satisfying tendon regeneration.

Interaction of Ceramic Implant Materials with Immune System

The immuno-compatibility of implant materials is a key issue for both initial and long-term implant integration. Ceramic implants have several advantages that make them highly promising for long-term medical solutions. These beneficial characteristics include such things as the material availability, possibility to manufacture various shapes and surface structures, osteo-inductivity and osteo-conductivity, low level of corrosion and general biocompatibility. The immuno-compatibility of an implant essentially depends on the interaction with local resident immune cells and, first of all, macrophages. However, in the case of ceramics, these interactions are insufficiently understood and require intensive experimental examinations. Our review summarizes the state of the art in variants of ceramic implants: mechanical properties, different chemical modifications of the basic material, surface structures and modifications, implant shapes and porosity. We collected the available information about the interaction of ceramics with the immune system and highlighted the studies that reported ceramic-specific local or systemic effects on the immune system. We disclosed the gaps in knowledge and outlined the perspectives for the identification to ceramic-specific interactions with the immune system using advanced quantitative technologies. We discussed the approaches for ceramic implant modification and pointed out the need for data integration using mathematic modelling of the multiple ceramic implant characteristics and their contribution for long-term implant bio- and immuno-compatibility.

Triple-functional bone adhesive with enhanced internal fixation, bacteriostasis and osteoinductive properties for open fracture repair

At present, effective fixation and anti-infection implant materials represent the mainstay for the treatment of open fractures. However, external fixation can cause nail tract infections and is ineffective for fixing small fracture fragments. Moreover, closed reduction and internal fixation during the early stage of injury can lead to potential bone infection, conducive to bone nonunion and delayed healing. Herein, we designed a bone adhesive with anti-infection, osteogenic and bone adhesion fixation properties to promote reduction and fixation of open fractures and subsequent soft tissue repair. It was prepared by the reaction of gelatin (Gel) and oxidized starch (OS) with vancomycin (VAN)-loaded mesoporous bioactive glass nanoparticles (MBGNs) covalently cross-linked with Schiff bases. Characterization and adhesion experiments were conducted to validate the successful preparation of the Gel-OS/VAN@MBGNs (GOVM-gel) adhesive. Meanwhile, in vitro cell experiments demonstrated its good antibacterial effects with the ability to stimulate bone marrow mesenchymal stem cell (BMSCs) proliferation, upregulate the expression of alkaline phosphatase (ALP) and osteogenic proteins (RunX2 and OPN) and enhance the deposition of calcium nodules. Additionally, we established a rat skull fracture model and a subcutaneous infection model. The histological analysis showed that bone adhesive enhanced osteogenesis, and in vivo experiments demonstrated that the number of inflammatory cells and bacteria was significantly reduced. Overall, the adhesive could promote early reduction of fractures and antibacterial and osteogenic effects, providing the foothold for treatment of this patient population.

Nanomaterials-Based Wound Dressing for Advanced Management of Infected Wound

The effective prevention and treatment of bacterial infections is imperative to wound repair and the improvement of patient outcomes. In recent years, nanomaterials have been extensively applied in infection control and wound healing due to their special physiochemical and biological properties. Incorporating antibacterial nanomaterials into wound dressing has been associated with improved biosafety and enhanced treatment outcomes compared to naked nanomaterials. In this review, we discuss progress in the application of nanomaterial-based wound dressings for advanced management of infected wounds. Focus is given to antibacterial therapy as well as the all-in-one detection and treatment of bacterial infections. Notably, we highlight progress in the use of nanoparticles with intrinsic antibacterial performances, such as metals and metal oxide nanoparticles that are capable of killing bacteria and reducing the drug-resistance of bacteria through multiple antimicrobial mechanisms. In addition, we discuss nanomaterials that have been proven to be ideal drug carriers for the delivery and release of antimicrobials either in passive or in stimuli-responsive manners. Focus is given to nanomaterials with the ability to kill bacteria based on the photo-triggered heat (photothermal therapy) or ROS (photodynamic therapy), due to their unparalleled advantages in infection control. Moreover, we highlight examples of intelligent nanomaterial-based wound dressings that can detect bacterial infections in-situ while providing timely antibacterial therapy for enhanced management of infected wounds. Finally, we highlight challenges associated with the current nanomaterial-based wound dressings and provide further perspectives for future improvement of wound healing.

Fabrication of biologically inspired electrospun collagen/silk fibroin/bioactive glass composited nanofibrous to accelerate the treatment efficiency of wound repair

A triple-layer matrix Collagen/Silk fibroin/Bioactive glass composited Nanofibrous was fabricated by linking electrospinning and freeze-drying systems, this typical three layered composite with a nanofibrous fragment as the key (top) layer, middle portion as inferior, and a spongy porous fragment as the third (bottom) deposit to develop the synergistic effect of composite materials resultant to physical and biological performances. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy were used to assess the final material's physicochemical properties (SEM). The triple-layer matrix had a nanofibrous and porous structure, which has qualities including high porosity, swelling, and stability, which are important in soft-tissue engineering. NIH 3 T3 fibroblast and humanoid keratinocyte (HaCaT) cell lines were also used to investigate the matrix's in vitro biological and fluorescent capabilities, which showed excellent cell adherence and proliferation across the composite layers. The synergistic arrangement of nanofibrous substantial deposition onto collagenous with silk fibroin candidates has therefore proven effective in the construction of a tri-layer matrix for skin-tissue-engineering applications.

Invigorating chronic wound healing by nanocomposites composed with bioactive materials: a comprehensive review

Wound healing research has revealed a plethora of data regarding various techniques for treating diverse types of wounds. It is well known that chronic wounds heal slowly and are vulnerable to infection. Also, there are numerous factors like destitute blood passage, undetermined inflammation, angiogenesis, neuropathy, and cell multiplication which overhang chronic wound healing. To eliminate the speculative features of chronic wounds, we made a consecutive survey on specific categories of biomaterials like bioglass, bioactive glass, bioceramics, biopolymers, and biocompatible metal oxide nanoparticles. In particular, the bioglass or bioactive glass which is a silica matrix composed of sodium, calcium, phosphorous, etc., is used for bone-bonding ability and easily dissolved in vivo conditions to repair damaged and wounded tissues with their peculiar physiochemical (surface area, porous nature, structural formation, mechanical stability) and biological properties (biocompatible, cytocompatible, osteoinductive, angiogenesis, hemostatic, antibacterial, and anti-inflammation). Furthermore, based on the existing literature studies, we summarized the healing of diabetes wound tendency by bioactive composite materials and offer detailed information on the method, techniques, and future technologies for wound healing.

Bioactive inorganic particles-based biomaterials for skin tissue engineering

The challenge for treatment of severe cutaneous wound poses an urgent clinical need for the development of biomaterials to promote skin regeneration. In the past few decades, introduction of inorganic components into material system has become a promising strategy for improving performances of biomaterials in the process of tissue repair. In this review, we provide a current overview of the development of bioactive inorganic particles-based biomaterials used for skin tissue engineering. We highlight the three stages in the evolution of the bioactive inorganic biomaterials applied to wound management, including single inorganic materials, inorganic/organic composite materials, and inorganic particles-based cell-encapsulated living systems. At every stage, the primary types of bioactive inorganic biomaterials are described, followed by citation of the related representative studies completed in recent years. Then we offer a brief exposition of typical approaches to construct the composite material systems with incorporation of inorganic components for wound healing. Finally, the conclusions and future directions are suggested for the development of novel bioactive inorganic particles-based biomaterials in the field of skin regeneration.

Bioactive glass-based fibrous wound dressings

Since the discovery of silicate bioactive glass (BG) by Larry Hench in 1969, different classes of BGs have been researched over decades mainly for bone regeneration. More recently, validating the beneficial influence of BGs with tailored compositions on angiogenesis, immunogenicity and bacterial infection, the applicability of BGs has been extended to soft tissue repair and wound healing. Particularly, fibrous wound dressings comprising BG particle reinforced polymer nanofibers and cotton-candy-like BG fibers have been proven to be successful for wound healing applications. Such fibrous dressing materials imitate the physical structure of skin's extracellular matrix and release biologically active ions e.g. regenerative, pro-angiogenic and antibacterial ions, e.g. borate, copper, zinc, etc., that can provoke cellular activities to regenerate the lost skin tissue and to induce new vessels formation, while keeping an anti-infection environment. In the current review, we discuss different BG fibrous materials meant for wound healing applications and cover the relevant literature in the past decade. The production methods for BG-containing fibers are explained and as fibrous wound dressing materials, their wound healing and bactericidal mechanisms, depending on the ions they release, are discussed. The present gaps in this research area are highlighted and new strategies to address them are suggested.

In-situ forming hydrogel based on thiolated chitosan/carboxymethyl cellulose (CMC) containing borate bioactive glass for wound healing

Suitable wound dressings for accelerating wound healing are actively being designed and synthesised. In this study, thiolated chitosan (tCh)/oxidized carboxymethyl cellulose (OCMC) hydrogel containing Cu-doped borate bioglass (BG) was developed as a wound dressing to improve wound healing in a full-thickness skin defect of mouse animal model. Thiolation was used to incorporate thiol groups into chitosan (Ch) to enhance its water solubility and mucoadhesion characteristics. Here, the in situ forming hydrogel was successfully developed using the Schiff-based reaction, and its physio-chemical and antibacterial characteristics were examined. Borate BG was also incorporated in the generated hydrogel to promote angiogenesis and tissue regeneration at the wound site. Investigations of in vitro cytotoxicity assays demonstrated that the synthesised hydrogels showed good biocompatibility and promoted cell growth. These results inspired us to investigate the effectiveness of skin wound healing in a mouse model. On the backs of animals, two full-thickness wounds were created and treated utilising two different treatment conditions: (1) OCMC/tCh hydrogel, (2) OCMC/tCh/borate BG, and (3) control defect. The wound closure ratio, collagen deposition, and angiogenesis activity were measured after 14 days to determine the healing efficacy of the in situ hydrogels used as wound dressings. Overall, the hydrogel containing borate BG was maintained in the defect site, healing efficiency was replicable, and wound healing was apparent. In conclusion, we found consistent angiogenesis, remodelling, and accelerated wound healing, which we propose may have beneficial effects on the repair of skin defects.

Gamma Radiation Induced Synthesis of Novel Chitosan/Gold/Bioactive Glass Nanocomposite for Promising Antimicrobial, and Antibiofilm Activities

In the present study we reported, for the first time, the gamma irradiation induced synthesis of chitosan/Au/bioactive glass (CS/Au/BG) nanocomposite. The bioactive glass (BG), with the composition 45% SiO2, 32.5% CaO, 15% Na2O, and 7.5% P2O5 wt% was synthesized through the sol–gel technique. XRD, SEM, EDX, and elemental mapping images were utilized to evaluate the structure of pure BG and CS/Au/BG nanocomposite. The antimicrobial efficacy was evaluated by zone of inhibition (ZOI), minimum inhibitory concentration (MIC), growth curve assay, and Ultraviolet irradiation effect. Investigation was carried on the antibiofilm effectiveness. Membrane leakage as well as SEM imaging were used to evaluate the antibacterial reaction mechanism. The crystallite size of CS/Au/BG nanocomposite was determined via Scherer equation as 22.83 nm. CS/Au/BG possessed the most ZOI activity against the tested microbes. The highest inhibition % of BG, and CS/Au/BG nanocomposite was investigated for S. aureus (15.65%, and 77.24%), followed by C. albicans (13.32%, and 64.75%). The quantity of protein leakage was directly-proportional after increasing the concentration of BG, and CS/Au/BG and counted to be 70.58, and 198.25 µg/mL, respectively (after applied 10 mg/mL). The promising results suggested the use of novel CS/Au/BG nanocomposite as an encourage candidate for wastewater treatment application against pathogenic microbes.

Dissolvable wound dressing loaded with silver nanoparticles together with ampicillin and ciprofloxacin

Aim: The current study is focused on the development of water-soluble wound dressings, which are potential dressings for the treatment of burn wounds. Materials & methods: Sodium alginate-based dissolvable wound dressings were prepared and loaded with silver nanoparticles and various antibiotics (ampicillin and ciprofloxacin) followed by characterization and in vitro antibacterial studies. Results & conclusions: The prepared sodium alginate-based dissolvable wound dressing exhibited good porosity, water uptake and moisture content, promising antibacterial activity, high absorption capacity of simulated wound exudates, excellent water vapor transmission rate in the range of 2000 to 5000 g/m² day^-1, sustained drug-release profiles and water solubility. The wound dressings were active against Proteus mirabilis, Staphylococcus aureus, Proteus vulgaris, Escherichia coli and Klebsiella aeruginosa strains of bacteria. The results obtained revealed the wound dressing as potential wound dressings for burn wounds and sensitive skin.

Coatings of hydroxyapatite-bioactive glass microparticles for adhesion to biological tissues

Adsorption of particles across interfaces has been proposed as a way to create adhesion between hydrogels and biological tissues. Here, we explore how this particle bridging approach can be applied to attach a soft polymer substrate to biological tissues, using bioresorbable and nanostructured hydroxyapatite-bioactive glass microparticles. For this, microparticles of aggregated flower-like hydroxyapatite and bioactive glass (HA-BG) were synthesized via a bioinspired route. A deposition technique using suspension spreading was developed to tune the coverage of HA-BG coatings at the surface of weakly cross-linked poly(beta-thioester) films. By varying the concentration of the deposited suspensions, we produced coatings having surface coverages ranging from 4% to 100% and coating densities ranging from 0.02 to 1.0 mg cm-2. The progressive dissolution of these coatings within 21 days in phosphate-buffered saline was followed by SEM. Ex vivo peeling experiments on pig liver capsules demonstrated that HA-BG coatings produce an up-to-two-fold increase in adhesion energy (9.8 ± 1.5 J m-2) as compared to the uncoated film (4.6 ± 0.8 J m-2). Adhesion energy was found to increase with increasing coating density until a maximum at 0.2 mg cm-2, well below full surface coverage, and then it decreased for larger coating densities. Using microscopy observations during and after peeling, we show that this maximum in adhesion corresponds to the appearance of particle stacks, which are easily separated and transferred onto the tissue. Such bioresorbable HA-BG coatings give the possibility of combining particle bridging with the storage and release of active compounds, therefore offering opportunities to design functional bioadhesive surfaces.

Borate Bioactive Glasses (BBG): Bone Regeneration, Wound Healing Applications, and Future Directions

Since the early 2000s, borate bioactive glasses (BBGs) have been extensively investigated for biomedical applications. The research so far indicates that BBGs frequently exhibit superior bioactivity and bone healing capacity compared to silicate glasses. They are also suitable candidates as drug delivery devices for infection or disease treatment such as osteoporosis. Additionally, BBGs are also an excellent option for wound healing applications, which includes the availability of commercial (FDA approved) microfibrous BBG dressings to treat chronic wounds. By addition of modifying ions, the bone or wound healing capacity of BBGs can be enhanced. For instance, addition of copper ions into BBGs was shown to drastically increase blood vessel formation for wound healing applications. Moreover, addition of ions such as magnesium, strontium, and cobalt improves bone healing. Other recent research interest related to BBGs is focused on nerve and muscle regeneration applications, while cartilage regeneration is also suggested as a potential application field for BBGs. BBGs are commonly produced by melt-quenching; however, sol-gel processing of BBGs is emerging and appears to be a promising alternative. In this review paper, the physical and biological characteristics of BBGs are analyzed based on the available literature, the applications of BBGs are discussed, and future research directions are suggested.