The Influence of PEG 4000 on the Physical and Microstructural Properties of 58S Bioactive Glasses.

Bioactive glass is currently considered a material with a high biocompatibility and has been used both in the field of bone regeneration and in the preparation of cosmetic products with the controlled release of active compounds. The present work involved a study on the synthesis of bioglass using the sol-gel process. The study aims to evaluate the influence of the treatment of bioglass with Polyethylene glycol 4000 (PEG 4000) on its main characteristics. The surface characteristics of this material were obtained by nitrogen adsorption/desorption analysis, using the standard BET (Brunauer-Emmett-Teller) equation, the crystallinity by XRD (X-ray diffraction) analysis, the surface structure by SEM (Scanning Electron Microscope), thermal stability by TGA (ThermoGravimetric Analyses), and chemical bonds changes by FTIR (Fourier transform infrared) spectroscopy. After treatment with PEG 4000, the average diameter of the pores increased insignificantly, the crystallinity peak disappeared, and the SEM analysis highlighted several clusters of very small sizes.

Multifunctional 3D matrixes based on flexible bioglass nanofibers for potential application in postoperative therapy of osteosarcoma.

Postoperative treatment of osteosarcoma is one of the major challenging clinical issues since both elimination of residual tumors and acceleration of bone regeneration should be considered. Photothermal therapy has been widely studied due to its advantages of small side-effect, low-toxicity, high local selectivity and noninversion, and bone tissue engineering is an inevitable trend in postoperative treatment of osteosarcoma. In this study, we combined the tissue engineering and photothermal therapy together, and developed a kind of multifunctional nanofibrous 3D matrixes for postoperative treatment of osteosarcoma. The flexible bioactive glass nanofibers (BGNFs) prepared by sol-gel electrospinning and calcination acted as the basic blocks, and the genipin-crosslinked gelatin (GNP-Gel) acted as the cement to bond the BGNFs forming a stable 3D structure. The stable porous 3D scaffolds were obtained through ice crystal templating method and freeze-drying technology. The obtained GNP-Gel/BGNF 3D matrixes showed a nanofibrous structure that highly biomimetics the extracellular matrix. The excellent compression recovery performance in water of these matrixes made them suitable for minimally invasive surgery. In addition, these 3D matrixes were not only biocompatible in vitro, but also benefit for the formation of mineralized bone in vivo. Furthermore, the dark blue GNP-Gel also acted as the photothermal agent, which endowed the GNP-Gel/BGNF 3D matrixes with efficient photothermal antitumor and photothermal antibacterial performance without addition of other toxic photothermal agents. Therefore, this study provides an ingenious avenue to prepare multifunctional nanofibrous 3D matrixes with photothermal therapy for postoperative treatment of osteosarcoma.

Exploring the potential of chitosan from royal shrimp waste for elaboration of chitosan/bioglass biocomposite: Characterization and "in vitro" bioactivity.

Exploiting royal shrimp waste to produce value-added biocomposites offers environmental and therapeutic benefits. This study proposes biocomposites based on chitosan and bioglass, using shrimp waste as the chitosan source. Chitin extraction and chitosan preparation were characterized using various analytical techniques. The waste composition revealed 24 % chitin, convertible to chitosan, with shells containing 77.33-ppm calcium. (X-ray diffraction) XRD analysis showed crystallinity index of 54.71 % for chitin and 49.14 % for chitosan. Thermal analysis indicated degradation rates of 326 °C and 322 °C, respectively. The degree of deacetylation of chitosan was 97.08 % determined by proton nuclear magnetic resonance (1H-NMR) analysis, with an intrinsic viscosity of 498 mL.g-1 and molar mass of 101,720 g/mol, showing improved solubility in 0.3 % acetic acid. Royal chitosan (CHR) was combined with bioglass (BG) via freeze-drying to create a CHR/BG biocomposite for bone surgery applications. The bioactivity of the CHR/BG was tested in simulated body fluid (SBF), revealing a biologically active apatite layer on its surface. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis confirmed enhanced bioactivity of the CHR/BG compared to commercial chitosan. The CHR/BG biocomposite demonstrated excellent apatite formation, validated by Scanning Electron Microscopy (SEM), highlighting its potential in bone surgery.

Amino acid surface modified bioglass: A candidate biomaterial for bone tissue engineering1.

Bioglasses are solid materials consisted of sodium oxide, calcium oxide, silicon dioxide and phosphorus in various proportions and have used in bone tissue engineering. There have been ongoing efforts to improve the surface properties of bioglasses to increase biocompatibility and performance. The aim of the present study is to modify the bioglass surface with an amino acid mixture consisting of arginine, aspartic acid, phenylalanine, cysteine, histidine and lysine, to characterize the surface, and to evaluate the performance and biocompatibility in vitro and in vivo. The untreated bioglass, bioglass kept in simulated body fluid (SBF), and modified bioglass were used in further evaluation. After confirmation of the surface modification with FT-IR analyses and SEM analyses, MC3T3-E1 preosteoblasts adhesion on the surface was also revealed by SEM. The modified bioglass had significantly higher ALP activity in colorimetric measurement, rate of calcium accumulations in Alizarin red s staining, lower rate of cell death in Annexin-V/PI staining to determine apoptosis and necrosis. Having higher cell viability rate in MTT test and absence of genotoxicity in micronucleus test (OECD 487), the modified bioglass was further confirmed for biocompatibility in vitro. The results of the rat tibial defect model revealed that the all bioglass treatments had a significantly better bone healing score compared to the untreated negative control. However, the modified bioglass exhibited significantly better bone healing efforts especially during the first and the second months compared to the other bioglass treatment treatments. As a result, the amino acid surface modification of bioglasses improves the surface biocompatibility and osteogenic performance that makes the amino acid modified bioglass a better candidate for bone tissue engineering. RESEARCH HIGHLIGHTS: Bioglass surface modification with amino acids contributes to bioglass-tissue interaction with an improved cell attachment. Modified bioglass increases in vitro Alp activity and calcium accumulation, and also positively affects cell behavior by supporting cell adaptation. Bioglass exerts osteogenic potential in vivo especially during early bone healing.

Employing novel biocompatible composite scaffolds with bioglass 58S and poly L-lactic acid for effective bone defect treatment.

BACKGROUND: Bioglass materials have gained significant attention in the field of tissue engineering due to their osteoinductive and biocompatible properties that promote bone cell differentiation. In this study, a novel composite scaffold was developed using a sol-gel technique to combine bioglass (BG) 58 S with a poly L-lactic acid (PLLA). METHODS AND RESULTS: The physiochemical properties, morphology, and osteoinductive potential of the scaffolds were investigated by X-ray diffraction analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results showed that the SiO2-CaO-P2O5 system was successfully synthesized by the sol-gel method. The PLLA scaffolds containing BG was found to be osteoinductive and promoted mineralization, as demonstrated by calcium deposition assay, upregulation of alkaline phosphatase enzyme activity, and Alizarin red staining data. CONCLUSIONS: These in vitro studies suggest that composite scaffolds incorporating hBMSCs are a promising substitute material to be implemented in bone tissue engineering. The PLLA/BG scaffolds promote osteogenesis and support the differentiation of bone cells, such as osteoblasts, due to their osteoinductive properties.

A Gelatin-Based Biomimetic Scaffold Promoting Osteogenic Differentiation of Adipose-Derived Mesenchymal Stem Cells.

Background: In bone tissue engineering segment, numerous approaches have been investigated to address critically sized bone defects via 3D scaffolds, as the amount of autologous bone grafts are limited, accompanied with complications on harvesting. Moreover, the use of bone-marrow-derived stem cells is also a limiting factor owing to the invasive procedures involved and the low yield of stem cells. Hence, research is ongoing on the search for an ideal bone graft system promoting bone growth and regeneration. Purpose of the Study: This study aims to develop a unique platform for tissue development via stem cell differentiation towards an osteogenic phenotype providing optimum biological cues for cell adhesion, differentiation and proliferation using biomimetic gelatin-based scaffolds. The use of adipose-derived mesenchymal stem cells in this study also offers an ideal approach for the development of an autologous bone graft. Methods: A gelatin-vinyl acetate-based 3D scaffold system incorporating Bioglass was developed and the osteogenic differentiation of adipose-derived mesenchymal stem cells (ADMSCs) on the highly porous freeze-dried gelatin-vinyl acetate/ Bioglass scaffold (GB) system was analyzed. The physicochemical properties, cell proliferation and viability were investigated by seeding rat adipose tissue-derived mesenchymal stem cells (ADSCs) onto the scaffolds. The osteogenic differentiation potential of the ADMSC seeded GeVAc/bioglass system was assessed using calcium deposition assay and bone-related protein and genes and comparing with the 3D Gelatin vinyl acetate coppolymer (GeVAc) constructs. Results and Conclusion: According to the findings, the 3D porous GeVAc/bioglass scaffold can be considered as a promising matrix for bone tissue regeneration and the 3D architecture supports the differentiation of the ADMSCs into osteoblast cells and enhances the production of mineralized bone matrix.

Cytotoxicity, Biocompatibility, and Calcium Deposition Capacity of 45S5 Bioglass Experimental Paste and Bio-C Temp: In Vitro and In Vivo Study Using Wistar Rats.

The evolution of biomaterials engineering allowed for the development of products that improve outcomes in the medical-dental field. Bioglasses have demonstrated the ability to either compose or replace different materials in dentistry. This study evaluated the cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp, compared to calcium hydroxide (Ca(OH)2) paste. The 45S5 bioglass and Ca(OH)2 powder were mixed with distilled water (ratio 2:1); Bio-C Temp is ready-for-use. Dental pulp cells were exposed to the materials' extracts (1:2 and 1:4 dilutions; 24, 48, and 72 h) for MTT and live/dead analyses. Polyethylene tubes filled with the pastes, or left empty (control), were implanted on the dorsum of 16 rats. After 7 and 30 days (n = 8/period), the rats were euthanized and the specimens were processed for hematoxylin-eosin (H&E), von Kossa (vK), and picrosirius red (PSR) staining, or without staining for polarized light (PL) birefringence analysis. A statistical analysis was applied (p < 0.05). There was no difference in cell viability among Ca(OH)2, 45S5 bioglass, and the control, across all periods and dilutions (p > 0.05), while Bio-C Temp was cytotoxic in all periods and dilutions compared to the control (p < 0.05). Regarding biocompatibility, there was a reduction in inflammation from 7 to 30 days for all groups, without significant differences among the groups for any period (p > 0.05). The fibrous capsules were thick for all groups at 7 days and thin at 30 days. All materials showed positive structures for vK and PL analysis. At 7 days, the control and 45S5 bioglass showed more immature collagen than the other groups (p < 0.05); at 30 days, 45S5 bioglass had more immature than mature collagen, different from the other groups (p < 0.05). In conclusion, Bio-C Temp presented cytotoxicity compared to the other materials, but the three pastes showed biocompatibility and induced calcium deposition. Additionally, the bioglass paste allowed for marked and continuous collagen proliferation. This study contributed to the development of new biomaterials and highlighted different methodologies for understanding the characteristics of medical-dental materials.

The Synthesis and Characterization of Selenium-Doped Bioglass.

Background Bioactive glass, which can form strong bonds with tissues, particularly bones, has become pivotal in tissue engineering. Incorporating biologically active ions like selenium enhances its properties for various biomedical applications, including bone repair and cancer treatment. Selenium's antioxidative properties and role in bone health make it a promising addition to biomaterial. Aim The present study was aimed at the preparation and characterization of selenium-doped bioglass. Materials and methods Tetraethyl orthosilicate (TEOS) was mixed with ethanol, water, and nitric acid to form a silica network and then supplemented with calcium nitrate, selenium acid sodium nitrate, and orthophosphoric acid. Sequential addition ensured specific functionalities. After sintering at 300 °C for three hours, the viscous solution transformed into powdered selenium-doped bioglass. Characterization involved scanning electron microscope (SEM) for microstructure analysis, attenuated total reflection infrared spectroscopy (ATR-IR) for molecular structure, and X-ray diffraction (XRD) for crystal structure analysis. Results SEM analysis of selenium-doped bioglass reveals a uniform distribution of selenium dopants in an amorphous structure, enhancing bioactivity through spherical particles with consistent size, micro-porosity, and roughness, facilitating interactions with biological fluids and tissues. ATR-IR analysis shows peaks corresponding to Si-O-Si and P-O bonds, indicating the presence of phosphate groups essential for biomedical applications within the bioglass network. XRD analysis confirms the amorphous nature of selenium-doped bioglass, with shifts in diffraction peaks confirming selenium incorporation without significant crystallization induction. Conclusion The selenium-infused bioglass displays promising versatility due to its amorphous structure, potentially enhancing interactions with biological fluids and tissues. Further research is needed to assess its impact on bone regeneration activity.

Development of Bioactive Hybrid Poly(lactic acid)/Poly(methyl methacrylate) (PLA/PMMA) Electrospun Fibers Functionalized with Bioglass Nanoparticles for Bone Tissue Engineering Applications.

Hybrid scaffolds that are based on PLA and PLA/PMMA with 75/25, 50/50, and 25/75 weight ratios and functionalized with 10 wt.% of bioglass nanoparticles (n-BG) were developed using an electrospinning technique with a chloroform/dimethylformamide mixture in a 9:1 ratio for bone tissue engineering applications. Neat PLA and PLA/PMMA hybrid scaffolds were developed successfully through a (CF/DMF) solvent system, obtaining a random fiber deposition that generated a porous structure with pore interconnectivity. However, with the solvent system used, it was not possible to generate fibers in the case of the neat PMMA sample. With the increase in the amount of PMMA in PLA/PMMA ratios, the fiber diameter of hybrid scaffolds decreases, and the defects (beads) in the fiber structure increase; these beads are associated with a nanoparticle agglomeration, that could be related to a low interaction between n-BG and the polymer matrix. The Young's modulus of PLA/PMMA/n-BG decreases by 34 and 80%, indicating more flexible behavior compared to neat PLA. The PLA/PMMA/n-BG scaffolds showed a bioactive property related to the presence of hydroxyapatite crystals in the fiber surface after 28 days of immersion in a Simulated Body Fluids solution (SBF). In addition, the hydrolytic degradation process of PLA/PMMA/n-BG, analyzed after 35 days of immersion in a phosphate-buffered saline solution (PBS), was less than that of the pure PLA. The in vitro analysis using an HBOF-1.19 cell line indicated that the PLA/PMMA/n-BG scaffold showed good cell viability and was able to promote cell proliferation after 7 days. On the other hand, the in vivo biocompatibility evaluated via a subdermal model in BALC male mice corroborated the good behavior of the scaffolds in avoiding the generation of a cytotoxic effect and being able to enhance the healing process, suggesting that the materials are suitable for potential applications in tissue engineering.

Bioglass and nano bioglass: A next-generation biomaterial for therapeutic and regenerative medicine applications.

Biomaterials are an indispensable component in tissue engineering that primarily functions to resemble the extracellular matrix of any tissue targeted for regeneration. In the last five decades, bioglass has been extensively used in the field of therapeutic and tissue engineering. The doping of metal components into bioglass and the synthesizing of nano bioglass particles have found remarkable implications, both in vivo and in vitro. These include various medical and biological applications such as rejuvenating tissues, facilitating regeneration, and delivering biomolecules into cells and therapy, etc. Therefore, the current review discusses the various techniques used in synthesizing bioglass particles, trends of various ion-doped nano bioglass, and their applications in therapy as well as in regenerative medicine, specifically in the fields of dentistry, cardiovascular, skin, nervous, and respiratory systems. Apart from these, this review also emphasizes the bioglass combined with diverse natural polymers (like collagen, chitosan, etc.) and their applications. Furthermore, we discuss the effectiveness of bioglass properties such as antibacterial effects, biomolecular delivery systems, tissue compatibility, and regenerative material. Finally, the prospects and limitations are elaborated.

In-Depth Characterization of Two Bioactive Coatings Obtained Using MAPLE on TiTaZrAg.

TiZrTaAg alloy is a remarkable material with exceptional properties, making it a unique choice among various industrial applications. In the present study, two types of bioactive coatings using MAPLE were obtained on a TiZrTaAg substrate. The base coating consisted in a mixture of chitosan and bioglass in which zinc oxide and graphene oxide were added. The samples were characterized in-depth through a varied choice of methods to provide a more complete picture of the two types of bioactive coating. The analysis included Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ellipsometry, and micro-Raman. The Vickers hardness test was used to determine the hardness of the films and the penetration depth. Film adhesion forces were determined using atomic force microscopy (AFM). The corrosion rate was highlighted by polarization curves and by using electrochemical impedance spectroscopy (EIS). The performed tests revealed that the composite coatings improve the properties of the TiZrTaAg alloy, making them feasible for future use as scaffold materials or in implantology.

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.

Engineered bacteria that self-assemble "bioglass" polysilicate coatings display enhanced light focusing.

Photonic devices are cutting-edge optical materials that produce narrow, intense beams of light, but their synthesis typically requires toxic, complex methodology. Here we employ a synthetic biology approach to produce environmentally-friendly, living microlenses with tunable structural properties. We engineered Escherichia coli bacteria to display the silica biomineralization enzyme silicatein from aquatic sea sponges. Our silicatein-expressing bacteria can self-assemble a shell of polysilicate "bioglass" around themselves. Remarkably, the polysilicate-encapsulated bacteria can focus light into intense nanojets that are nearly an order of magnitude brighter than unmodified bacteria. Polysilicate-encapsulated bacteria are metabolically active for up to four months, potentially allowing them to sense and respond to stimuli over time. Our data demonstrate that engineered bacterial particles have the potential to revolutionize the development of multiple optical and photonic technologies.

Antibacterial and Osteogenic Doxycycline Imprinted Bioglass Microspheres to Combat Bone Infection.

Currently, postoperative infection is a significant challenge in bone and dental surgical procedures, demanding the exploration of innovative approaches due to the prevalence of antibiotic-resistant bacteria. This study aims to develop a strategy for controlled and smart antibiotic release while accelerating osteogenesis to expedite bone healing. In this regard, temperature-responsive doxycycline (DOX) imprinted bioglass microspheres (BGMs) were synthesized. Following the formation of chitosan-modified BGMs, poly N-isopropylacrylamide (pNIPAm) was used for surface imprinting of DOX. The temperature-responsive molecularly imprinted polymers (MIPs) exhibited pH and temperature dual-responsive adsorption and controlled-release properties for DOX. The temperature-responsive MIP was optimized by investigating the molar ratio of N,N'-methylene bis(acrylamide) (MBA, the cross-linker) to NIPAm. Our results demonstrated that the MIPs showed superior adsorption capacity (96.85 mg/g at 35 °C, pH = 7) than nonimprinted polymers (NIPs) and manifested a favorable selectivity toward DOX. The adsorption behavior of DOX on the MIPs fit well with the Langmuir model and the pseudo-second-order kinetic model. Drug release studies demonstrated a controlled release of DOX due to imprinted cavities, which were fitted with the Korsmeyer-Peppas kinetic model. DOX-imprinted BGMs also revealed comparable antibacterial effects against Staphylococcus aureus and Escherichia coli to the DOX (control). In addition, MIPs promoted viability and osteogenic differentiation of MG63 osteoblast-like cells. Overall, the findings demonstrate the significant potential of DOX-imprinted BGMs for use in bone defects. Nonetheless, further in vitro investigations and subsequent in vivo experiments are warranted to advance this research.

Evaluation of new bone formation in critical-sized rat calvarial defect using 3D printed polycaprolactone/tragacanth gum-bioactive glass composite scaffolds.

Critical-sized bone defects are a major challenge in reconstructive bone surgery and usually fail to be treated due to limited remaining bone quality and extensive healing time. The combination of 3D-printed scaffolds and bioactive materials is a promising approach for bone tissue regeneration. In this study, 3D-printed alkaline-treated polycaprolactone scaffolds (M-PCL) were fabricated and integrated with tragacanth gum- 45S5 bioactive glass (TG-BG) to treat critical-sized calvarial bone defects in female adult Wistar rats. After a healing period of four and eight weeks, the new bone of blank, M-PCL, and M-PCL/TG-BG groups were harvested and assessed. Micro-computed tomography, histological, biochemical, and biomechanical analyses, gene expression, and bone matrix formation were used to assess bone regeneration. The micro-computed tomography results showed that the M-PCL/TG-BG scaffolds not only induced bone tissue formation within the bone defect but also increased BMD and BV/TV compared to blank and M-PCL groups. According to the histological analysis, there was no evidence of bony union in the calvarial defect regions of blank groups, while in M-PCL/TG-BG groups bony integration and repair were observed. The M-PCL/TG-BG scaffolds promoted the Runx2 and collagen type I expression as compared with blank and M-PCL groups. Besides, the bone regeneration in M-PCL/TG-BG groups correlated with TG-BG incorporation. Moreover, the use of M-PCL/TG-BG scaffolds promoted the biomechanical properties in the bone remodeling process. These data demonstrated that the M-PCL/TG-BG scaffolds serve as a highly promising platform for the development of bone grafts, supporting bone regeneration with bone matrix formation, and osteogenic features. Our results exhibited that the 3D-printed M-PCL/TG-BG scaffolds are a promising strategy for successful bone regeneration.

Cobalt/Bioglass Nanoparticles Enhanced Dermal Regeneration in a 3-Layered Electrospun Scaffold.

Purpose: Due to the multilayered structure of the skin tissue, the architecture of its engineered scaffolds needs to be improved. In the present study, 45s5 bioglass nanoparticles were selected to induce fibroblast proliferation and their protein secretion, although cobalt ions were added to increase their potency. Methods: A 3-layer scaffold was designed as polyurethane (PU) - polycaprolactone (PCL)/ collagen/nanoparticles-PCL/collagen. The scaffolds examined by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), tensile, surface hydrophilicity and weight loss. Biological tests were performed to assess cell survival, adhesion and the pattern of gene expression. Results: The mechanical assay showed the highest young modulus for the scaffold with the doped nanoparticles and the water contact angle of this scaffold after chemical crosslinking of collagen was reduced to 52.34±7.7°. In both assessments, the values were statistically compared to other groups. The weight loss of the corresponding scaffold was the highest value of 82.35±4.3 % due to the alkaline effect of metal ions and indicated significant relations in contrast to the scaffold with non-doped particles and bare one (P value<0.05). Moreover, better cell expansion, greater cell confluence and a lower degree of toxicity were confirmed. The up-regulation of TGF ß1 and VEGF genes introduced this scaffold as a better model for the fibroblasts commitment to a new skin tissue among bare and nondoped scaffold (P value<0.05). Conclusion: The 3-layered scaffold which is loaded with cobalt ions-bonded bioglass nanoparticles, is a better substrate for the culture of the fibroblasts.

The Effect of Bioglass Coating on Microshear Bond Strength of Resin Cement to Zirconia.

Objectives: Durable bonding to zirconia is a challenging issue in dentistry. This study aimed to assess the effect of bioglass coating of zirconia on the microshear bond strength of resin cement to zirconia and to study the effect of thermocycling on this bond. Materials and Methods: This in-vitro experimental study was conducted on 60 yttria-stabilized tetragonal zirconia blocks in six groups (N=10) based on surface pretreatment and thermocycling. Surface pretreatments included no treatment control, alumina particle abrasion, and bioglass-coating of zirconia. Resin bonding was performed with Panavia F2.0 cements. Then, half of the specimens underwent a 24-hour incubation in 37°C water, while the other half were subjected to thermocycling (12000 cycles, 5-55°C, 60s for each batch) following the same incubation period. Subsequently, the microshear bond strength of the specimens was measured. Additionally, one block from each group was subjected to scanning electron microscopy and X-ray diffraction. The data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Results: There was a significant difference between the bond strength values of different groups (P<0.001). Alumina particle abrasion and bioglass coating equally increased the bond strength compared to the untreated control group (P<0.001). Thermocycling caused significant decreases in bond strength in all the groups (P<0.001); however, the bond strength value of the thermocycled bioglass-coated group was significantly higher than that reported for the thermocycled alumina particle abraded group (P=0.015). Conclusion: Despite the decrease in the bond strength values after thermocycling, the long-term efficacy of the bioglass coating of zirconia was promising.

Recent trends in bone tissue engineering: a review of materials, methods, and structures.

Bone tissue engineering (BTE) provides the treatment possibility for segmental long bone defects that are currently an orthopedic dilemma. This review explains different strategies, from biological, material, and preparation points of view, such as using different stem cells, ceramics, and metals, and their corresponding properties for BTE applications. In addition, factors such as porosity, surface chemistry, hydrophilicity and degradation behavior that affect scaffold success are introduced. Besides, the most widely used production methods that result in porous materials are discussed. Gene delivery and secretome-based therapies are also introduced as a new generation of therapies. This review outlines the positive results and important limitations remaining in the clinical application of novel BTE materials and methods for segmental defects.

Update on the use of 45S5 bioactive glass in the treatment of bone defects in regenerative medicine.

Bone regeneration is a critical area in regenerative medicine, particularly in orthopedics, demanding effective biomedical materials for treating bone defects. 45S5 bioactive glass (45S5 BG) is a promising material because of its osteoconductive and bioactive properties. As research in this field continues to advance, keeping up-to-date on the latest and most successful applications of this material is imperative. To achieve this, we conducted a comprehensive search on PubMed/MEDLINE, focusing on English articles published in the last decade. Our search used the keywords "bioglass 45S5 AND bone defect" in combination. We found 27 articles, and after applying the inclusion criteria, we selected 15 studies for detailed examination. Most of these studies compared 45S5 BG with other cement or scaffold materials. These comparisons demonstrate that the addition of various composites enhances cellular biocompatibility, as evidenced by the cells and their osteogenic potential. Moreover, the use of 45S5 BG is enhanced by its antimicrobial properties, opening avenues for additional investigations and applications of this biomaterial.

Exploring the Impact of Copper Oxide Substitution on Structure, Morphology, Bioactivity, and Electrical Properties of 45S5 Bioglass®.

In recent decades, the requirements for implantable medical devices have increased, but the risks of implant rejection still exist. These issues are primarily associated with poor osseointegration, leading to biofilm formation on the implant surface. This study focuses on addressing these issues by developing a biomaterial for implant coatings. 45S5 bioglass® has been widely used in tissue engineering due to its ability to form a hydroxyapatite layer, ensuring a strong bond between the hard tissue and the bioglass. In this context, 45S5 bioglasses®, modified by the incorporation of different amounts of copper oxide, from 0 to 8 mol%, were synthesized by the melt-quenching technique. The incorporation of Cu ions did not show a significant change in the glass structure. Since the bioglass exhibited the capacity for being polarized, thereby promoting the osseointegration effectiveness, the electrical properties of the prepared samples were studied using the impedance spectroscopy method, in the frequency range of 102-106 Hz and temperature range of 200-400 K. The effects of CuO on charge transport mobility were investigated. Additionally, the bioactivity of the modified bioglasses was evaluated through immersion tests in simulated body fluid. The results revealed the initiation of a Ca-P-rich layer formation on the surface within 24 h, indicating the potential of the bioglasses to enhance the bone regeneration process.