Mesoporous 45S5 bioactive glass: synthesis, in vitro dissolution and biomineralization behavior

The Effect of Iron Oxide Insertion on the In Vitro Bioactivity, and Antibacterial Properties of the 45S5 Bioactive Glass

The aging population and increasing incidence of trauma among younger age groups have heightened the increasing demand for reliable implant materials. Effective implant materials must demonstrate rapid osseointegration and strong antibacterial properties to ensure optimal patient outcomes and decrease the chance of implant rejection. This study aims to enhance the bone-implant interface by utilizing 45S5 bioglass modified with various concentrations of Fe3O4 as a coating material. The effect of the insertion of Fe3O4 into the bioglass structure was studied using Raman spectroscopy which shows that with the increase in Fe3O4 concentration, new vibration bands associated with Fe-related structural units appeared within the sample. The bioactivity of the prepared glasses was evaluated using immersion tests in simulated body fluid, revealing the formation of a calcium phosphate-rich layer within 24 h on the samples, indicating their potential for enhanced tissue integration. However, the sample modified with 8 mol% of Fe3O4 showed low reactivity, developing a calcium phosphate-rich layer within 96 h. All the bioglasses showed antibacterial activity against the Gram-positive and Gram-negative bacteria. The modified bioglass did not present significant antibacterial properties compared to the bioglass base.

Cell-free chitosan/silk fibroin/bioactive glass scaffolds with radial pore for in situ inductive regeneration of critical-size bone defects

Tissue-engineered is an effective method for repairing critical-size bone defects. The application of bioactive scaffold provides artificial matrix and suitable microenvironment for cell recruitment and extracellular matrix deposition, which can effectively accelerate the process of tissue regeneration. Among various scaffold properties, appropriate pore structure and distribution have been proven to play a crucial role in inducing cell infiltration differentiation and in-situ tissue regeneration. In this study, a chitosan (CS) /silk fibroin (SF) /bioactive glass (BG) composite scaffold with distinctive radially oriented pore structure was constructed. The composite scaffolds had stable physical and chemical properties, a unique pore structure of radial arrangement from the center to the periphery and excellent mechanical properties. In vitro biological studies indicated that the CS/SF/BG scaffold could promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the expression of related genes due to the wide range of connected pore structures and released active elements. Furthermore, in vivo study showed CS/SF/BG scaffold with radial pores was more conducive to the repair of skull defects in rats with accelerated healing speed during the bone tissue remodeling process. These results demonstrated the developed CS/SF/BG scaffold would be a promising therapeutic strategy for the repair of bone defects regeneration.

The unexplored role of alkali and alkaline earth elements (ALAEs) on the structure, processing, and biological effects of bioactive glasses

Bioactive glass has been employed in several medical applications since its inception in 1969. The compositions of these materials have been investigated extensively with emphasis on glass network formers, therapeutic transition metals, and glass network modifiers. Through these experiments, several commercial and experimental compositions have been developed with varying chemical durability, induced physiological responses, and hydroxyapatite forming abilities. In many of these studies, the concentrations of each alkali and alkaline earth element have been altered to monitor changes in structure and biological response. This review aims to discuss the impact of each alkali and alkaline earth element on the structure, processing, and biological effects of bioactive glass. We explore critical questions regarding these elements from both a glass science and biological perspective. Should elements with little biological impact be included? Are alkali free bioactive glasses more promising for greater biological responses? Does this mixed alkali effect show increased degradation rates and should it be employed for optimized dissolution? Each of these questions along with others are evaluated comprehensively and discussed in the final section where guidance for compositional design is provided.

Engineering mesoporous bioactive glasses for emerging stimuli-responsive drug delivery and theranostic applications

Mesoporous bioactive glasses (MBGs), which belong to the category of modern porous nanomaterials, have garnered significant attention due to their impressive biological activities, appealing physicochemical properties, and desirable morphological features. They hold immense potential for utilization in diverse fields, including adsorption, separation, catalysis, bioengineering, and medicine. Despite possessing interior porous structures, excellent morphological characteristics, and superior biocompatibility, primitive MBGs face challenges related to weak encapsulation efficiency, drug loading, and mechanical strength when applied in biomedical fields. It is important to note that the advantageous attributes of MBGs can be effectively preserved by incorporating supramolecular assemblies, miscellaneous metal species, and their conjugates into the material surfaces or intrinsic mesoporous networks. The innovative advancements in these modified colloidal inorganic nanocarriers inspire researchers to explore novel applications, such as stimuli-responsive drug delivery, with exceptional in-vivo performances. In view of the above, we outline the fabrication process of calcium-silicon-phosphorus based MBGs, followed by discussions on their significant progress in various engineered strategies involving surface functionalization, nanostructures, and network modification. Furthermore, we emphasize the recent advancements in the textural and physicochemical properties of MBGs, along with their theranostic potentials in multiple cancerous and non-cancerous diseases. Lastly, we recapitulate compelling viewpoints, with specific considerations given from bench to bedside.

Devitrite (Na2Ca3Si6O16) phase dominated nanostructured 45S5 bioactive glass: exploring its structural and biological properties

This research study is primarily centred around calcination temperature and time influence on phase formation in bioactive glasses (BGs). In the present study, BG with a nominal composition of 45S5 was synthesized through the sol-gel process. The developed BGs then underwent heat treatment for various sintering durations and temperatures. X-ray diffraction (XRD) patterns of the BGs reveals that the sintering process led to the crystallization of both devitrite (Na2Ca3Si6O16) and combeite (Na2Ca2Si3O9) phases. The field emission scanning electron microscopy study divulges morphological alterations, from sheet-like to rod-like structures to eventually transforming into spherical and sheet-like structures. The surface area and Type-IV mesoporous porosity were validated through Brunauer Emmett Teller analysis, highlighting a notable increase in pore volume and mechanical strength at a lower sintering temperature.In vitroapatite formation was carried out in Hank's balance salt in order to evaluate the bioactivity of the glass. After 7 d of immersion in simulated body fluid (SBF), XRD patterns and scanning electron microscopy micrographs results showed that formation of hydroxyapatite layer on the surface of the BGs. The BG compatibility with erythrocytes (red blood cells) was also studied, and the results revealed that there was only a low 2% lysis, showing good hemocompatibility. The drug loading and release behaviour of the BGs was studied in thein vitroanalysis. The findings showed a high drug encapsulation effectiveness of up to 90% and continuous drug release from the BGs for 24 h. The materials biocompatibility was unambiguously confirmed by cytocompatibility and proliferation studies. This study provides compelling evidence for the exceptional efficacy and promise of the distinct 45S5 BGs in advancing the field of regenerative medicine.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Review of Physical, Mechanical, and Biological Characteristics of 3D-Printed Bioceramic Scaffolds for Bone Tissue Engineering Applications

This review focuses on the advancements in additive manufacturing techniques that are utilized for fabricating bioceramic scaffolds and their characterizations leading to bone tissue regeneration. Bioscaffolds are made by mimicking the human bone structure, material composition, and properties. Calcium phosphate apatite materials are the most commonly used scaffold materials as they closely resemble live bone in their inorganic composition. The functionally graded scaffolds are fabricated by utilizing the right choice of the 3D printing method and material combinations to achieve the requirement of the bioscaffold. To tailor the physical, mechanical, and biological properties of the scaffold, certain materials are reinforced, doped, or coated to incorporate the functionality. The biomechanical loading conditions that involve flexion, torsion, and tension exerted on the implanted scaffold are discussed. The finite element analysis (FEA) technique is used to investigate the mechanical property of the scaffold before fabrication. This helps in reducing the actual number of samples used for testing. The FEA simulated results and the experimental result are compared. This review also highlights some of the challenges associated while processing the scaffold such as shrinkage, mechanical instability, cytotoxicity, and printability. In the end, the new materials that are evolved for tissue engineering applications are compiled and discussed.

Preparation and In Vitro Osteogenic Evaluation of Biomimetic Hybrid Nanocomposite Scaffolds Based on Gelatin/Plasma Rich in Growth Factors (PRGF) and Lithium-Doped 45s5 Bioactive Glass Nanoparticles

Bone tissue engineering is an emerging technique for repairing large bone lesions. Biomimetic techniques expand the use of organic-inorganic spongy-like nanocomposite scaffolds and platelet concentrates. In this study, a biomimetic nanocomposite scaffold was prepared using lithium-doped bioactive-glass nanoparticles and gelatin/PRGF. First, sol-gel method was used to prepare bioactive-glass nanoparticles that contain 0, 1, 3, and 5%wt lithium. The lithium content was then optimized based on antibacterial and MTT testing. By freeze-drying, hybrid scaffolds comprising 5, 10, and 20% bioglass were made. On the scaffolds, human endometrial stem cells (hEnSCs) were cultured for adhesion (SEM), survival, and osteogenic differentiation. Alkaline phosphatase activity and osteopontin, osteocalcin, and Runx2 gene expression were measured. The effect of bioactive-glass nanoparticles and PRGF on nanocomposites' mechanical characteristics and glass-transition temperature (T _g) was also studied. An optimal lithium content in bioactive glass structure was found to be 3% wt. Nanoparticle SEM examination indicated grain deformation due to different sizes of lithium and sodium ions. Results showed up to 10% wt bioactive-glass and PRGF increased survival and cell adhesion. Also, Hybrid scaffolds revealed higher ALP-activity and OP, OC, and Runx2 gene expression. Furthermore, bioactive-glass has mainly increased ALP-activity and Runx2 expression, whereas PRGF increases the expression of OP and OC genes. Bioactive-glass increases scaffold modulus and T _g continuously. Hence, the presence of both bioactive-glass and nanocomposite scaffold improves the expression of osteogenic differentiation biomarkers. Subsequently, it seems that hybrid scaffolds based on biopolymers, Li-doped bioactive-glass, and platelet extracts can be a good strategy for bone repair.

An enduring in vitro wound healing phase recipient by bioactive glass-graphene oxide nanocomposites

Bioactive glass (BG) is an interesting topic in soft tissue engineering because of its biocompatibility and bonding potential to increase fibroblast cell proliferation, synthesize growth factors, and stimulate granulation tissue development. The proposed BG with and without sodium (Na), prepared by the sol–gel method, is employed in wound healing studies. The BG/graphene oxide (GO) and BG (Na-free)/GO nanocomposites were investigated against fibroblast L929 cells in vitro; the 45S5 BG nanocomposites exhibited desired cell viability (80%), cell proliferation (30%), cell migration (25%), metabolic activity, and wound contraction due to extracellular matrix (ECM) production and enhanced protein release by fibroblast cells. Additionally, the antioxidant assays for BG, BG (Na-free), GO, and BG/GO, BG (Na-free)/GO were evaluated for effective wound healing properties. The results showed decreased inflammation sites in the wound area, assessed by the (2,2-diphenyl-1-picryl-hydrazyl-hydrate) (DPPH) assay with ~ 80% radical scavenging activity, confirming their anti-inflammatory and improved wound healing properties.

Dual-Drug Delivery via Zein In Situ Forming Implants Augmented with Titanium-Doped Bioactive Glass for Bone Regeneration: Preparation, In Vitro Characterization, and In Vivo Evaluation

In situ forming implants (IFIs) are non-surgical approach using biodegradable polymers to treat bone fractures. The study aimed at preparing dual-drug-loaded IFIs to deliver pitavastatin (osteogenic drug) and tedizolid (antibiotic) using zein as the implant matrix via solvent-induced phase inversion method. At first, several investigations were done on pitavastatin-loaded zein IFIs, where three concentrations of zein were used (10, 20, and 30% w/v). IFIs were evaluated for their solidification time, rheological properties, injectability, and in vitro release. IFIs containing bioactive glass nanoparticles were prepared by the addition of non-doped bioactive glass nanoparticles (BGT0; 1, 3, 5, and 10% w/v) or titanium-doped bioactive glass nanoparticles (BGT5; 1% w/v) to the selected concentration of zein (30% w/v) and then evaluated. The optimized dual-medicated implant (D-ZIFI 1) containing pitavastatin, tedizolid, sodium hyaluronate (3% w/v), and BGT5 (1% w/v) was prepared and compared to IFI lacking both sodium hyaluronate and BGT5 (D-ZIFI 2). D-ZIFI 1 and 2 sustained the release profiles of both drugs for 28 days. SEM images proved the interconnected porous structure of D-ZIFI 1 due to sodium hyaluronate. In vivo studies on surgically induced bone defects in Sprague-Dawley rats signified the proper accelerated bone healing ability of D-ZIFI 1 over D-ZIFI 2. Results presented D-ZIFI 1 as a promising, effective, non-surgical approach for bone healing.

Bioglass promotes wound healing by inhibiting endothelial cell pyroptosis through regulation of the connexin 43/reactive oxygen species (ROS) signaling pathway

Bioactive glass (BG) has recently shown great promise in soft tissue repair, especially in wound healing; however, the underlying mechanism remains unclear. Pyroptosis is a novel type of programmed cell death that is involved in various traumatic injury diseases. Here, we hypothesized that BG may promote wound healing through suppression of pyroptosis. To test this scenario, we investigated the possible effect of BG on pyroptosis in wound healing both in vivo and in vitro. This study showed that BG can accelerate wound closure, granulation formation, collagen deposition, and angiogenesis. Moreover, western blot analysis and immunofluorescence staining revealed that BG inhibited the expression of pyroptosis-related proteins in vivo and in vitro. In addition, while BG regulated the expression of connexin43 (Cx43), it inhibited reactive oxygen species (ROS) production. Cx43 activation and inhibition experiments further indicate that BG inhibited pyroptosis in endothelial cells by decreasing Cx43 expression and ROS levels. Taken together, these studies suggest that BG promotes wound healing by inhibiting pyroptosis via Cx43/ROS signaling pathway.

Mesoporous Bioactive Glasses in Cancer Diagnosis and Therapy: Stimuli-Responsive, Toxicity, Immunogenicity, and Clinical Translation

Cancer is one of the top life-threatening dangers to the human survival, accounting for over 10 million deaths per year. Bioactive glasses have developed dramatically since their discovery 50 years ago, with applications that include therapeutics as well as diagnostics. A new system within the bioactive glass family, mesoporous bioactive glasses (MBGs), has evolved into a multifunctional platform, thanks to MBGs easy-to-functionalize nature and tailorable textural properties-surface area, pore size, and pore volume. Although MBGs have yet to meet their potential in tumor treatment and imaging in practice, recently research has shed light on the distinguished MBGs capabilities as promising theranostic systems for cancer imaging and therapy. This review presents research progress in the field of MBG applications in cancer diagnosis and therapy, including synthesis of MBGs, mechanistic overview of MBGs application in tumor diagnosis and drug monitoring, applications of MBGs in cancer therapy ( particularly, targeted delivery and stimuli-responsive nanoplatforms), and immunological profile of MBG-based nanodevices in reference to the development of novel cancer therapeutics.

Injectable hydrogel for postoperative synergistic photothermal-chemodynamic tumor and anti-infection therapy

Tumor surgery is usually accompanied by neoplasm residual, tissue defects, and multi-drug resistant bacterial infection, causing high tumor recurrence, low survival rate, and chronic wounds. Herein, a light-activated injectable hydrogel based on bioactive nanocomposite system is developed by incorporating Ag₂S nanodots conjugated Fe-doped bioactive glass nanoparticles (BGN-Fe-Ag₂S) into biodegradable PEGDA and AIPH solution for inhibiting tumor growth, treating bacterial infection, and promoting wound healing. Under laser irradiation, the photothermal effect mediated by Ag₂S nanodots would trigger the decomposition of AIPH, generating alkyl radicals to initiate the gelation of PEGDA. The in-situ gelatinized hydrogel, with outstanding photothermal effect and chemodynamic effect derived from the doped Fe in BGN-Fe-Ag₂S, can not only eliminate multidrug-resistant bacteria but also efficiently ablated tumor during treatment. Moreover, the hydrogel significantly accelerated wound healing with more skin appendages in the full-thickness cutaneous wounds model because of the hydrolysis of bioactive glass. These results manifest that this multifunctional hydrogel is a suitable biomaterial to inhibit tumor proliferation and overcome tissue bacterial infection after surgical removal of tumors.

Synthesis and Characterization of ZnO(MgO)-CaO-SiO2-P2O5 Bioglass Obtained by Sol-Gel Method in Presence of Surfactant Agent

Bioglass (BG) is a class of biomaterials increasingly approached in biomedical applications, such as in regeneration of hard tissues, due to the properties of bioactivity, osteoinductivity, osteoconductivity, but also the high rate of biodegradation, both in vitro and in vivo. The present paper addresses the obtaining of bioglasses from the ZnO(MgO)-CaO-SiO₂-P₂O₅ system by the sol-gel method and the use of a surfactant to ensure a specific surface or high open porosity, starting from S53P4 bioglass (53% SiO₂, 23% Na₂O, 20% CaO, 4% P₂O₅), also known as BoneAlive^®. The precursor powders were analyzed from the phase composition point of view by complex thermal analysis and X-ray diffraction, the vitreous powders were assessed from the compositional point of view by X-ray diffraction, morpho-structural by scanning electron microscopy, specific surface area and the pore size dimension by the Brunauer–Emmett–Teller (BET) analysis, dispersion by laser granulometry, and also cell biology and surface mineralization tests were performed by immersion in SBF (simulated body fluid). The system proposed in this paper ZnO(MgO)-CaO-SiO₂-P₂O₅ was successfully obtained by sol-gel method. The results showed the higher interaction between the samples and the SBF medium for samples containing magnesium (M2) and the lowest degree of mineralization after immersion in SBF was noticed for samples containing zinc (M1). The results also prove that by incorporating different ionic species in bioglass composition—Zn²⁺ and Mg²⁺, biocompatibility and antibacterial properties will be significantly enhanced.

Preparation and characterization of chitosan/carboxymethyl pullulan/bioglass composite films for wound healing

Wound dressings play a vital role in the wound healing process. Although a variety of wound dressings have been developed so far, most of them still have many drawbacks such as rigidity, non-porosity, low mechanical strength, an affinity to stick onto the injury surface and less antimicrobial activity. To overcome these issues, a novel type of porous three-dimensional (3D) film was fabricated using chitosan/carboxymethyl pullulan polyelectrolyte complex (PEC) loaded with 45S5 bioglass (CCMPBG) by the freeze-drying method for wound healing application. The developed films were analysed by FTIR, XRD, EDS and SEM to confirm their chemical nature, microstructure and surface morphologies. The CCMPBG films exhibited rough surface morphology and well-interconnected micropores with an average size range of 101-74 μm. Compared to the control chitosan/carboxymethyl pullulan (CCMP) film, the CCMPBG films showed an enhanced mechanical strength and controlled rate of swelling and biodegradation behaviours due to the interaction of polymer matrix and 45S5 bioglass (BG). Furthermore, CCMPBG films presented the improved biocompatibility, antimicrobial activity and wound closure ability because of the synergistic effects of chitosan, carboxymethyl pullulan (CMP) and BG. The results demonstrated that CCMPBG films can be an effective dressing material for wound therapy.

Investigating the Intermediate Water Feature of Hydrated Titanium Containing Bioactive Glass

Intermediate water (IW) in hydrated bioactive glasses remains uninvestigated. We obtained titanium (Ti)-containing bioactive glasses (BGTs) (Ti at 5%, 7.5% and 10% of the glass system) using the sol-gel technique. Their thermal, physicochemical, and morphological properties, before and after Ti-doping, were analysed using DTA, XRD, FTIR, TEM, and SEM accessorised with EDAX, and size distribution and zeta potential surface charges were determined using a NanoZetasizer. The IW in hydrated BGTs was investigated by cooling and heating runs of DSC measurements. Moreover, the mode of death in an osteosarcoma cell line (MG63) was evaluated at different times of exposure to BGT discs. Ti doping had no remarkable effect on the thermal, physicochemical, and morphological properties of BGTs. However, the morphology, size, and charges of BGT nano-powders were slightly changed after inclusion of Ti compared with those of BGT0; for example, the particle size increased with increasing Ti content (from 4-5 to 7-28 nm). The IW content was enhanced in the presence of Ti. The mode of cell death revealed the effect of IW content on the proliferation of cells exposed to BGTs. These findings should help improve the biocompatibility of inorganic biomaterials.

Biosensitive and antibacterial coatings on metallic material for medical applications

Metallic materials are commonly used for load-bearing implants and as internal fixation devices. It is customary to use austenitic stainless steel, especially surgical grade type 316L SS as temporary and Ti alloys as permanent implants. However, long-term, poor bonding with bone, corrosion, and release of metal ions, such as chromium and nickel occur. These ions are powerful allergens and carcinogens and their uncontrolled leaching may be avoided by surface coatings. Therefore, bioactive glasses (BGs) became a vital biomedical material, which can form a biologically active phase of hydroxycarbonate apatite on their surface when in contact with physiological fluids. To reduce the high coefficient of friction and the brittle nature of BGs, polymers are normally incorporated to avoid the high-temperature sintering/densification of ceramic-only coatings. For medical application, electrophoretic deposition (EPD) is now used for polymer (organic) and ceramic (inorganic) components at room temperature due to its simplicity, control of coating thickness and uniformity, low cost of equipment, ability to coat substrates of intricate shape and to supply thick films in composite form, high purity of deposits as well as no phase transformation during coating. Although extensive research has been conducted on polymer/inorganic composite coatings, only some studies have reported multifunctional properties, such as biological antibacterial activity, enhanced cell adhesion, controlled drug release ability, and mechanical properties. This review will focus on biodegradable coatings, including zien, chitosan, gelatin, cellulose loaded with antibacterial drugs/metallic ions/natural herbs on biostable substrates (PEEK/PMMA/PCL/PLLA layers), which have the potential of multifunctional coating for metallic implants.

Characterization of Hybrid Materials Prepared by Sol-Gel Method for Biomedical Implementations. A Critical Review

The interaction between tissues and biomaterials (BM) has the purpose of improving and replacing anatomical parts of the human body, avoiding the occurrence of adverse reactions in the host organism. Unfortunately, the early failure of implants cannot be currently avoided, since neither a good mixture of mechanical and chemical characteristics of materials nor their biocompatibility has been yet achieved. Bioactive glasses are recognized to be a fine class of bioactive substances for good repair and replacement. BM interact with living bones through the formation of a hydroxyapatite surface layer that is analogous to bones. Bioglasses' composition noticeably affects their biological properties, as does the synthesis method, with the best one being the versatile sol-gel technique, which includes the change of scheme from a 'sol' fluid into a 'gel'. This process is widely used to prepare many materials for biomedical implants (e.g., hip and knee prostheses, heart valves, and ceramic, glassy and hybrid materials to serve as carriers for drug release). Nanoparticles prepared by the sol-gel method are interesting systems for biomedical implementations, and particularly useful for cancer therapy. This review provides many examples concerning the synthesis and characterization of the above-mentioned materials either taken from literature and from recently prepared zirconia/polyethylene glycol (PEG) hybrids, and the corresponding results are extensively discussed.

Tailorable Zinc-Substituted Mesoporous Bioactive Glass/Alginate-Methylcellulose Composite Bioinks

Bioactive glasses have been used for bone regeneration applications thanks to their excellent osteoconductivity, an osteostimulatory effect, and high degradation rate, releasing biologically active ions. Besides these properties, mesoporous bioactive glasses (MBG) are specific for their highly ordered mesoporous channel structure and high specific surface area, making them suitable for drug and growth factor delivery. In the present study, calcium (Ca) (15 mol%) in MBG was partially and fully substituted with zinc (Zn), known for its osteogenic and antimicrobial properties. Different MBG were synthesized, containing 0, 5, 10, or 15 mol% of Zn. Up to 7 wt.% of Zn-containing MBG could be mixed into an alginate-methylcellulose blend (algMC) while maintaining rheological properties suitable for 3D printing of scaffolds with sufficient shape fidelity. The suitability of these composites for bioprinting applications has been demonstrated with immortalized human mesenchymal stem cells. Uptake of Ca and phosphorus (P) (phosphate) ions by composite scaffolds was observed, while the released concentration of Zn2+ corresponded to the initial amount of this ion in prepared glasses, suggesting that it can be controlled at the MBG synthesis step. The study introduces a tailorable bioprintable material system suitable for bone tissue engineering applications.

Bioactive glasses and glass-ceramics for hyperthermia treatment of cancer: state-of-art, challenges, and future perspectives

Bioactive glasses and glass-ceramics are well-proven potential biomaterials for bone-tissue engineering applications because of their compositional flexibility. Many research groups have been focused to explore the utility of bioactive glass-ceramics beyond bone engineering to hyperthermia treatment of cancer. Hyperthermia refers to raising the temperature of tumor close to 44°C at which malignant cells perish with negligible harm to normal cells. Hyperthermia can be employed by many means such as by ultrasonic waves, electromagnetic waves, infrared radiations, alternating magnetic fields, etc. Magnetic bioactive glass-ceramics are advantageous over other potential candidates for thermoseeds such as nanofluids, superparamagnetic nanoparticles because they can bond not only to the natural bone but also with soft tissues in few cases, which helps regenerating the affected part due to its bioactive nature. Strict restrictions on clinical settings ( H × f < 5 × 10 9 ) force the research activities to be more focused on material characteristics to raise the implant temperature to required ranges. Lots of efforts have been made in past years to tackle these challenges and design best-suited glass-ceramics for hyperthermia treatment. This review aims to provide essential information on the concept of hyperthermia treatment of cancer and recent developments in the field of bioactive glass-ceramics for cancer treatment. The advantages and disadvantages of magnetic glass-ceramics over other potential thermoseed materials are highlighted. In this field, the major challenges are to develop magnetic glasses, which have fast and bulk crystallization with optimized magnetic phases with lower Curie and Neel temperatures.

Insight into the impingement of different sodium precursors on structural, biocompatible, and hemostatic properties of bioactive materials

Bioactive materials play a significant role in biomedical engineering for plethora of applications. To date, there is no evident report on the role of sodium precursors in structural changes towards their acceleration in biocompatibility. This study highlights the impact and role of two different sodium precursors (sodium nitrate and sodium hydroxide) on the structural changes and their potential formulations in biomineralization and biocompatibility. Structural characteristics enunciate the significant crystallization of NaCaPO₄, Na₂Ca₂Si₃O₉, and Na_1.8Ca_1.1Si₆O₁₄ phases with pertinent Q² stretching's while using sodium nitrate than sodium hydroxide. XPS spectra authenticate the elevated sodium content while using sodium nitrate as sodium precursor. One-dimensional structures with well faceted morphology and superior alkaline environment preferentially support the biomineralization and bactericidal properties in sodium nitrate-bioglass, was confirmed through structural, morphological, elemental, and antibacterial investigations. Whereas, higher blood and cell-line compatibility with elevated protein adsorption rate is perceived for the bioglass prepared using sodium hydroxide source, and subsequently, higher hemostatic properties are considerably observed with sodium nitrate-bioglass. Higher mechanical stability (ultrasonic measurements) and controlled degradation rate are the stratagems of sodium nitrate to boost the basic criteria of bioactive materials. Hence, it is proposed that sodium nitrate is a highly preferable source to develop bioactive and stable bioglass formulations.

A Guided Walk through the World of Mesoporous Bioactive Glasses (MBGs): Fundamentals, Processing, and Applications

Bioactive glasses (BGs) are traditionally known to be able to bond to living bone and stimulate bone regeneration. The production of such materials in a mesoporous form allowed scientists to dramatically expand the versatility of oxide-based glass systems as well as their applications in biomedicine. These nanostructured materials, called mesoporous bioactive glasses (MBGs), not only exhibit an ultrafast mineralization rate but can be used as vehicles for the sustained delivery of drugs, which are hosted inside the mesopores, and therapeutic ions, which are released during material dissolution in contact with biological fluids. This review paper summarizes the main strategies for the preparation of MBGs, as well as their properties and applications in the biomedical field, with an emphasis on the methodological aspects and the promise of hierarchical systems with multiscale porosity.

Interplay between surface chemistry and osteogenic behaviour of sulphate substituted nano-hydroxyapatite

Surface potential and chemical compositions of the bioceramics are the core of therapeutic effect and are key factors to trigger the interfacial interactions with surrounding hard and soft tissues to repair and regeneration. Ionic substitution in hydroxyapatite (Hap) lattice significantly influences the zeta potential from -16.46 ± 0.66 mV to -6.01 ± 0.68 mV as well as an average nano-rod length from ~40 nm to ~26 nm with respect to SO₄^2- ion content. Moreover, the surface chemistry of Hap is mainly inter-related to SO₄^2- substitution rate at PO₄^2- site. Specifically, nano-sized feature with lowered negative surface potential influences the protein adsorption via their weak repulsive or attractive forces. Bovine serum albumin (BSA) and lysozyme (LSZ) adsorption studies confirmed the increased affinity to active binding sites of Hap's surface. Further, SO₄^2- ion substituted Hap (SNHA) showed improved in vitro biomineralization activity and alkaline phosphatase activity. Expression of osteogenic biomarkers such as collagen I, V, osteopontin and osteocalcin were evaluated in Saos-2 and MC3T3-E1 cells. Gene expression of these markers was influenced by SO₄^2- ion content in Hap (maximum with 10SNHA). Altogether, these data emphasizes that chemical composition and surface properties are dominant aspect in bioceramic development towards bone regeneration.

Phase selection of calcium carbonate crystals under the induction of lignin monomer model compounds

The formation and application of ‘cinnamic acid & CaCO₃ crystals’ (CACs) induced by a lignin monomer compound.

Exploration of gum ghatti-modified porous scaffolds for bone tissue engineering applications

Taking advantage of the tissue engineering principles, the formed hydroxyl apatite-modified gum ghatti biomaterial with its porous nature, biocompatibility, and efficient mechanical properties can be potential for the bone repair and regeneration.