Fabrication and characterization of strontium incorporated 3-D bioactive glass scaffolds for bone tissue from biosilica

The Effect of Silver and Samarium on the Properties of Bioglass Coatings Produced by Pulsed Laser Deposition and Spin Coating

The current study reports the use of silver (Ag) and samarium (Sm) as dopants to improve the properties of standard bioglass in terms of biological performance. This experiment considers thin films of doped bioglass obtained by pulsed laser deposition (PLD) and spin coating (SC). For both methods, some parameters were gradually varied, as the main objective was to produce a bioglass that could be used in biomedical fields. In order to study the morphology, the phase composition and other properties, the samples obtained were subjected to multiple analyses, such as thermal analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FT-IR), Raman spectroscopy, and x-ray diffraction (XRD). Furthermore, the in vitro bioactivity of the samples, as assessed through simulated body fluid (SBF) immersion, as well as immunocytochemistry and evaluation of actin filaments, assessed through fluorescence microscopy, are reported. The results confirmed the formation of the designed vitreous target employed as the source of material in the PLD experiments only at sintering temperatures below 800 °C; this vitreous nature was preserved in the grown film as well. The presence of Ag and Ce dopants in the parent glassy matrix was validated for all stages, from powder, to target, to PLD/SC-derived coatings. Additionally, it was demonstrated that the surface topography of the layers can be adjusted by using substrates with different roughness or by modulating the processing parameters, such as substrate temperature and working pressure in PLD, rotation speed, and number of layers in SC. The developed material was found to be highly bioactive after 28 days of immersion in SBF, but it was also found to be a potential candidate for inhibiting the growth of Gram-negative bacteria and a suitable support for cell growth and proliferation.

Nano-SiO2 reinforced alginate-chitosan-gelatin nanocomposite hydrogels with improved physicochemical properties and biological activity

Alginate (Alg) hydrogels possess desirable advantages for application in tissue engineering; however, they are limited by their weak mechanical properties, poor chronical stability in phosphate buffered saline, and absence of mammalian cell recognition sites, severely restricting their biomedical applications. To overcome these limitations, we integrated Alg hydrogels with nano-silica (SiO2) to produce nano-SiO2 reinforced Alg-chitosan-gelatin nanocomposite hydrogels (Alg/SiO2-CHI-GA NCH) for biomedical purposes, utilizing Chitosan (CHI) and gelatin (GA) in an alternate electrostatic adsorption. Specifically, we investigated the regulatory and promotional effects of the nano-SiO2 on the morphological structure, mechanical properties, thermal stability, rheological properties, swelling, biodegradability, biomineralization and cytocompatibility of the resultant Alg/SiO2-CHI-GA NCH. The experimental findings demonstrate that the constructed Alg/SiO2-CHI-GA NCH exhibited uniform morphology and a regular structure. Upon freeze-drying, the internal cross-sections of the NCH exhibited a honeycomb porous structure. Furthermore, the physicochemical properties and biological activities of the prepared Alg/SiO2-CHI-GA NCH were regulated to some extent by nano-SiO2 content. Notably, nano-SiO2 inclusion enhanced the attachment and viability of MG63 and MC3T3-E1 cells and induced three-dimensional cell growth in ALG/SiO2-CHI-GA NCH. Among the fabricated NCH, Alg/SiO2-CHI-GA NCH with 0.5% and 1.0% (w/v) nano-SiO2 exhibited significant proliferative activity, which is attributable to their high porosity and uniform cell adhesion. Furthermore, the alkaline phosphatase activity in the cells gradually increased with increasing of nano-SiO2 amount, indicating the favorable effect of nano-SiO2 on the osteogenic differentiation of MG63 and MC3T3-E1 cells. Our study findings provide a comprehensive foundation for the structural- and property-related limitations of Alg hydrogels in biomedicine, thereby expanding their potential applications in tissue engineering.

Evaluation of biocomposite putty with strontium and zinc co-doped 45S5 bioactive glass and sodium hyaluronate

The application of powder or granule formed bioactive glasses in the defect area with the help of a liquid carrier to fill the defects is a subject of interest and is still open to development. In this study, it was aimed to prepare biocomposites of bioactive glasses incorporating different co-dopants with a carrier biopolymer and to create a fluidic material (Sr and Zn co-doped 45S5 bioactive glasses‑sodium hyaluronate). All biocomposite samples were pseudoplastic fluid type, which may be suitable for defect filling and had excellent bioactivity behaviors confirmed by FTIR, SEM-EDS and XRD. Biocomposites with Sr and Zn co-doped bioactive glass had higher bioactivity considering the crystallinity of hydroxyapatite formations compared to biocomposite with undoped bioactive glasses. Biocomposites with high bioactive glass content had hydroxyapatite formations with higher crystallinity compared to biocomposites with low bioactive glass. Furthermore, all biocomposite samples showed non-cytotoxic effect on the L929 cells up to a certain concentration. However, biocomposites with undoped bioactive glass showed cytotoxic effects at lower concentrations compared to biocomposites with co-doped bioactive glass. Thus, biocomposite putties utilizing Sr and Zn co-doped bioactive glasses may be advantageous for orthopedic applications due to their specified rheological, bioactivity, and biocompatibility properties.

Release kinetics modelling and in vivo-vitro, shelf-life study of resveratrol added composite transdermal scaffolds

In this article, the suitability of composite transdermal biomaterial for wound dressing applications is discussed. Bioactive, antioxidant Fucoidan and Chitosan biomaterials were doped into polyvinyl alcohol/β-tricalcium phosphate based polymeric hydrogels loaded with Resveratrol, which has theranostic properties, and biomembrane design with suitable cell regeneration properties was aimed. In accordance with this purpose, tissue profile analysis (TPA) was performed for the bioadhesion properties of composite polymeric biomembranes. Fourier Transform Infrared Spectrometry (FT-IR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM-EDS) analyses were performed for morphological and structural analyses of biomembrane structures. In vitro Franz diffusion mathematical modelling of composite membrane structures, biocompatibility (MTT test) and in vivo rat tests were performed. TPA analysis of resveratrol loaded biomembrane scaffold design; compressibility; 13.4 ± 1.9(g.s), hardness; 16.8 ± 1(g), adhesiveness; -11 ± 2.0(g.s), elasticity; 0.61 ± 0.07, cohesiveness; 0.84 ± 0.04 were found. Proliferation of the membrane scaffold was 189.83 % at 24 h and 209.12 % at 72 h. In the in vivo rat test; at the end of 28th day, it was found that biomembrane_3 provided 98.75 ± 0.12 % wound shrinkage. The shelf-life of RES in the transdermal membrane scaffold, which was determined as Zero order according to Fick's law in in vitro Franz diffusion mathematical modelling, was found to be approximately 35 days by Minitab statistical analysis. The importance of this study is that the innovative and novel transdermal biomaterial supports tissue cell regeneration and cell proliferation in theranostic applications as a wound dressing.

Application of bioactive metal ions in the treatment of bone defects

The treatment of bone defects is an important problem in clinical practice. The rapid development of bone tissue engineering (BTE) may provide a new method for bone defect treatment. Metal ions have been widely studied in BTE and demonstrated a significant effect in promoting bone tissue growth. Different metal ions can be used to treat bone defects according to specific conditions, including promoting osteogenic activity, inhibiting osteoclast activity, promoting vascular growth, and exerting certain antibacterial effects. Multiple studies have confirmed that metal ions-modified composite scaffolds can effectively promote bone defect healing. By studying current extensive research on metal ions in the treatment of bone defects, this paper reviews the mechanism of metal ions in promoting bone tissue growth, analyzes the loading mode of metal ions, and lists some specific applications of metal ions in different types of bone defects. Finally, this paper summarizes the advantages and disadvantages of metal ions and analyzes the future research trend of metal ions in BTE. This article can provide some new strategies and methods for future research and applications of metal ions in the treatment of bone defects.

Facile Fabrication of 3D-Printed Porous Ti6Al4V Scaffolds with a Sr-CaP Coating for Bone Regeneration

To improve osseointegration caused by the stress-shielding effect and the inert nature of titanium-based alloys, in this work, we successfully constructed a strontium calcium phosphate (Sr-CaP) coating on three-dimensional (3D)-printed Ti6Al4V scaffolds to address this issue. The energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) results indicated that the coatings with and without Sr doping mainly consisted of CaHPO₄. The bonding strength of Sr doping coating met the required ISO 13 779-4-2018 standard (≥15 MPa). The in vitro results suggested that the Sr-CaP-modified Ti6Al4V scaffolds were found to effectively promote mice bone-marrow stem cell (mBMSC) adhesion, spreading, and osteogenesis. The in vivo experiments also showed that the Sr-CaP-modified Ti6Al4V scaffolds could significantly improve bone regeneration and osseointegration. More importantly, Sr-doped CaP-coated Ti6Al4V scaffolds were found to accelerate bone healing in comparison to CaP-coated Ti6Al4V scaffolds. The Sr-CaP-modified Ti6Al4V scaffolds are considered a promising strategy to develop bioactive surfaces for enhancing the osseointegration between the implant and bone tissue.

Hybrid biofabrication of 3D osteoconductive constructs comprising Mg-based nanocomposites and cell-laden bioinks for bone repair

Tissue engineering approaches for bone repair have rapidly evolved due to the development of novel biofabrication technologies, providing an opportunity to fabricate anatomically-accurate living implants with precise placement of specific cell types. However, limited availability of biomaterial inks, that can be 3D-printed with high resolution, while providing high structural support and the potential to direct cell differentiation and maturation towards the osteogenic phenotype, remains an ongoing challenge. Aiming towards a multifunctional biomaterial ink with high physical stability and biological functionality, this work describes the development of a nanocomposite biomaterial ink (Mg-PCL) comprising of magnesium hydroxide nanoparticles (Mg) and polycaprolactone (PCL) thermoplastic for 3D printing of strong and bioactive bone regenerative scaffolds. We characterised the Mg nanoparticle system and systematically investigated the cytotoxic and osteogenic effects of Mg supplementation to human mesenchymal stromal cells (hMSCs) 2D-cultures. Next, we prepared Mg-PCL biomaterial ink using a solvent casting method, and studied the effect of Mg over mechanical properties, printability and scaffold degradation. Furthermore, we delivered MSCs within Mg-PCL scaffolds using a gelatin-methacryloyl (GelMA) matrix, and evaluated the effect of Mg over cell viability and osteogenic differentiation. Nanocomposite Mg-PCL could be printed with high fidelity at 20 wt% of Mg content, and generated a mechanical reinforcement between 30%-400% depending on the construct internal geometry. We show that Mg-PCL degrades faster than standard PCL in an accelerated-degradation assay, which has positive implications towards in vivo implant degradation and bone regeneration. Mg-PCL did not affect MSCs viability, but enhanced osteogenic differentiation and bone-specific matrix deposition, as demonstrated by higher ALP/DNA levels and Alizarin Red calcium staining. Finally, we present proof of concept of Mg-PCL being utilised in combination with a bone-specific bioink (Sr-GelMA) in a coordinated-extrusion bioprinting strategy for fabrication of hybrid constructs with high stability and synergistic biological functionality. Mg-PCL further enhanced the osteogenic differentiation of encapsulated MSCs and supported bone ECM deposition within the bioink component of the hybrid construct, evidenced by mineralised nodule formation, osteocalcin (OCN) and collagen type-I (Col I) expression within the bioink filaments. This study demonstrated that magnesium-based nanocomposite bioink material optimised for extrusion-based 3D printing of bone regenerative scaffolds provide enhanced mechanical stability and bone-related bioactivity with promising potential for skeletal tissue regeneration.

Evaluation of bioactive glass scaffolds incorporating SrO or ZnO for bone repair: In vitro bioactivity and antibacterial activity

A series of bioactive glass scaffolds doped with SrO or ZnO (0, 5, and 10 mol%) were synthesized by the foam replica and melting method. The thermodynamic evolution, phase composition, microstructure, ion release, in vitro bioactivity, and oxygen density of the scaffolds were characterized. The proliferation of murine long bone osteocyte Y4 cells was studied by cell culture. The survival rate of the BGs evaluated the antibacterial activity and Escherichia coli strains in co-culture. The results indicated that the process window decreases with the increase of dopants. All the samples have a pore structure size of 200-400 μm. When the scaffolds were immersed in simulated body fluid for 28 days, hydroxyapatite formation was not affected, but the degradation process was retarded. The glass network packing and ionic radii variations of the substitution ions control surface degradation, glass dissolution, and ion release. MTT results revealed that 5Sr-BG had a significant effect on promoting cell proliferation and none of the BGs were cytotoxicity. Sr-BGs and Zn-BGs exhibited significantly inhibited growth against E. coli bacterial strains. Generally, these results showed the 5Sr-BG scaffold with high vitro bioactivity, cell proliferation, and antibacterial property is an important candidate material for bone tissue regeneration and repair.

Dual Network Composites of Poly(vinyl alcohol)-Calcium Metaphosphate/Alginate with Osteogenic Ions for Bone Tissue Engineering in Oral and Maxillofacial Surgery

Despite considerable advances in biomaterials-based bone tissue engineering technologies, autografts remain the gold standard for rehabilitating critical-sized bone defects in the oral and maxillofacial (OMF) region. A majority of advanced synthetic bone substitutes (SBS’s) have not transcended the pre-clinical stage due to inferior clinical performance and translational barriers, which include low scalability, high cost, regulatory restrictions, limited advanced facilities and human resources. The aim of this study is to develop clinically viable alternatives to address the challenges of bone tissue regeneration in the OMF region by developing ‘dual network composites’ (DNC’s) of calcium metaphosphate (CMP)—poly(vinyl alcohol) (PVA)/alginate with osteogenic ions: calcium, zinc and strontium. To fabricate DNC’s, single network composites of PVA/CMP with 10% (w/v) gelatine particles as porogen were developed using two freeze–thawing cycles and subsequently interpenetrated by guluronate-dominant sodium alginate and chelated with calcium, zinc or strontium ions. Physicochemical, compressive, water uptake, thermal, morphological and in vitro biological properties of DNC’s were characterised. The results demonstrated elastic 3D porous scaffolds resembling a ‘spongy bone’ with fluid absorbing capacity, easily sculptable to fit anatomically complex bone defects, biocompatible and osteoconductive in vitro, thus yielding potentially clinically viable for SBS alternatives in OMF surgery.

Bioactive glass: A multifunctional delivery system

Bioactive glasses (BAGs) were invented five decades ago and have been widely used clinically in orthopedic and stomatology. However, in the past two decades, BAGs have been explored immensely by several researchers worldwide as a multifunctional delivery system for a multitude of therapeutics ranging from metal ions to small molecules (e.g., drugs) and macromolecules (e.g., DNA). The impetus for devising a BAG-based delivery system in the 21st century is based upon the facilitative properties it offers for entrapment of a wide range of therapeutic molecules and the tailorable controlled release kinetics to the target tissue site along with the biological activity of the ionic dissolution products in several pathological conditions such as osteoporosis, cancer, infection, and inflammation. This review comprises two parts: the first part discusses the need for a new delivery system and how the journey from melt quench progressed towards template-based sol-gel mesoporous. In the second part, we have comprehended the scientific advancements made so far, emphasizing BAGs as a delivery system ranging from therapeutic ions to phytopharmaceuticals. We have also highlighted a few loopholes that have prevented bench-to-bedside clinical translation of a plethora of elucidative researches done so far.

Tellurium: A new active element for innovative multifunctional bioactive glasses

Bioactive glasses have been widely investigated for their ability to release ions with therapeutic effect. In this paper, a silica based bioactive glass was doped with a low amount of tellurium dioxide (1 and 5 mol%) to confer antibacterial and antioxidant properties. The obtained glasses were characterized in terms of morphology, composition, structure, characteristic temperatures and in vitro bioactivity. Moreover, comprehensive analyses were carried out to estimate the cytocompatibility, the antibacterial and antioxidant properties of Te-doped glasses. The performed characterizations demonstrated that the Te insertion did not interfere with the amorphous nature of the glass, the substitution of SiO₂ with TeO₂ led to a slight decrease in T_g and a TeO₂ amount higher than 1 mol% can induce a change in the primary crystal field. In vitro bioactivity test demonstrated the Te-doped glass ability to induce the precipitation of hydroxyapatite. Finally, the biological characterization showed a strong antibacterial and antioxidant effects of Te-containing glasses in comparison with the control glass, demonstrating that Te is a promising element to enhance the biological response of biomaterials.

Mimicking the electrophysiological microenvironment of bone tissue using electroactive materials to promote its regeneration

The process of bone tissue repair and regeneration is complex and requires a variety of physiological signals, including biochemical, electrical and mechanical signals, which collaborate to ensure functional recovery. The inherent piezoelectric properties of bone tissues can convert mechanical stimulation into electrical effects, which play significant roles in bone maturation, remodeling and reconstruction. Electroactive materials, including conductive materials, piezoelectric materials and electret materials, can simulate the physiological and electrical microenvironment of bone tissue, thereby promoting bone regeneration and reconstruction. In this paper, the structures and performances of different types of electroactive materials and their applications in the field of bone repair and regeneration are reviewed, particularly by providing the results from in vivo evaluations using various animal models. Their advantages and disadvantages as bone repair materials are discussed, and the methods for tuning their performances are also described, with the aim of providing an up-to-date account of the proposed topics.

Fabrication of chitosan-coated porous polycaprolactone/strontium-substituted bioactive glass nanocomposite scaffold for bone tissue engineering

In the present study, porous (about 70 vol%) nanocomposite scaffolds made of polycaprolactone (PCL) and different amounts (0 to 15 wt%) of 45S bioactive glass (BG) nanoparticles (with a particle size of about 40 nm) containing 7 wt% strontium (Sr) were fabricated by solvent casting technique for bone tissue engineering. Then, a selected optimum scaffold was coated with a thin layer of chitosan containing 15 wt% Sr-substituted BG nanoparticles. Several techniques such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), tensile test, and water contact angle measurement were used to characterize the fabricated samples. In vitro experiments including degradation, bioactivity, and biocompatibility (i.e., cytotoxicity, alkaline phosphate activity, and cell adhesion) tests of the fabricated scaffold were performed. The biomedical behavior of the fabricated PCL-based composite scaffold was interpreted by considering the presence of the porosity, Sr-substituted BG nanoparticles, and the chitosan coating. In conclusion, the fabricated chitosan-coated porous PCL/BG nanocomposite containing 15 wt% BG nanoparticles could be utilized as a good candidate for bone tissue engineering.

Composite Membranes of Poly(ε-caprolactone) with Bisphosphonate-Loaded Bioactive Glasses for Potential Bone Tissue Engineering Applications

Poly(ε-caprolactone) (PCL) is a bioresorbable synthetic polyester with numerous biomedical applications. PCL membranes show great potential in guided tissue regeneration because they are biocompatible, occlusive and space maintaining, but lack osteoconductivity. Therefore, two different types of mesoporous bioactive glasses (SiO2-CaO-P2O5 and SiO2-SrO-P2O5) were synthesized and incorporated in PCL thin membranes by spin coating. To enhance the osteogenic effect of resulting membranes, the bioglasses were loaded with the bisphosphonate drug ibandronate prior to their incorporation in the polymeric matrix. The effect of the composition of the bioglasses as well as the presence of absorbed ibandronate on the physicochemical, cell attachment and differentiation properties of the PCL membranes was evaluated. Both fillers led to a decrease of the crystallinity of PCL, along with an increase in its hydrophilicity and a noticeable increase in its bioactivity. Bioactivity was further increased in the presence of a Sr substituted bioglass loaded with ibandronate. The membranes exhibited excellent biocompatibility upon estimation of their cytotoxicity on Wharton's Jelly Mesenchymal Stromal Cells (WJ-SCs), while they presented higher osteogenic potential in comparison with neat PCL after WJ-SCs induced differentiation towards bone cells, which was enhanced by a possible synergistic effect of Sr and ibandronate.

Multiple and Promising Applications of Strontium (Sr)-Containing Bioactive Glasses in Bone Tissue Engineering

Improving and accelerating bone repair still are partially unmet needs in bone regenerative therapies. In this regard, strontium (Sr)-containing bioactive glasses (BGs) are highly-promising materials to tackle this challenge. The positive impacts of Sr on the osteogenesis makes it routinely used in the form of strontium ranelate (SR) in the clinical setting, especially for patients suffering from osteoporosis. Therefore, a large number of silicate-, borate-, and phosphate-based BGs doped with Sr and produced in different shapes have been developed and characterized, in order to be used in the most advanced therapeutic strategies designed for the management of bone defects and injuries. Although the influence of Sr incorporation in the glass is debated regarding the obtained physicochemical and mechanical properties, the biological improvements have been found to be substantial both in vitro and in vivo. In the present study, we provide a comprehensive overview of Sr-containing glasses along with the current state of their clinical use. For this purpose, different types of Sr-doped BG systems are described, including composites, coatings and porous scaffolds, and their applications are discussed in the light of existing experimental data along with the significant challenges ahead.

Preparation and Characterization of Nanocomposite Scaffolds (Collagen/β-TCP/SrO) for Bone Tissue Engineering

Background

Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications.

Methods

In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (β-TCP) and strontium oxide (SrO). A composition of β-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/β-TCP (1:2 w/w), and COL/β-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization.

Results

All the scaffolds had a microporous structure with high porosity (~ 95-99%) and appropriate pore size (100-200 μm). COL/β-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/β-TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of β-TCP-Sr to collagen scaffolds increased ALP activity by 1.33-1.79 and 2.92-4.57 folds after 7 and 14 days of culture, respectively.

Conclusion

In summary, it was found that the incorporation of Sr into the collagen-β-TCP scaffolds has a great potential for bone tissue engineering applications.

A comparative study on the in vitro formation of hydroxyapatite, cytotoxicity and antibacterial activity of 58S bioactive glass substituted by Li and Sr

Lithium and strontium up to 10 mol% have been substituted for calcium in 58S bioactive glasses in order to enhance specific biological properties such as proliferation, alkaline phosphatase (ALP) activity of cells as well as antibacterial activity. In-vitro formation of hydroxyapatite was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma atomic emission spectrometry (ICP-AES) and scanning electron microscopy (SEM). Substitution of either Li or Sr for Ca in the composition had a retarding effect on the bioactivity while Li decreased and Sr increased the rate of ion release in the simulated body fluid solution. The dissolution rate showed to be inversely proportional to oxygen density of the bioactive glasses. The proposed mechanisms for the lowered bioactivity are a lower supersaturation degree for nucleation of apatite in Li substituted bioactive glasses and blocking of the active growth sites of calcium phosphate by Sr²⁺ in Sr substituted bioactive glasses. The proliferation rate and alkaline phosphate activity of osteoblast cell line MC3T3-E1 treated with Li and Sr bioactive glasses were studied. 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alkaline phosphate assay showed that all synthesized bioactive glasses with exception of 58S with 10 mol% SrO, exhibited statistically significant increase in both cell proliferation and alkaline phosphatase activity. Finally, 58S bioactive glass with 5 mol% Li₂O substitution for CaO was considered as a potential biomaterial in bone repair/regeneration therapies with enhanced biocompatibility, and alkaline phosphate activity, with a negligible loss in the bioactivity compared to the 58S bioglass. At the same time this composition had the highest antibacterial activity against methicillin-resistant Staphylococcus aureus bacteria among all synthesized Li and Sr substituted bioactive glasses.

Bio-templated silica composites for next-generation biomedical applications

Silica-based materials have extensive biomedical applications owing to their unique physical, chemical, and biological properties. Recently, increasing studies have examined the mechanisms involved in biosilicification to develop novel, fine-tunable, eco-friendly materials and/or technologies. In this review, we focus on recent developments in bio-templated silica synthesis and relevant applications in drug delivery systems, tissue engineering, and biosensing.

Poly (fumaroyl bioxirane) maleate: A potential functional scaffold for bone regeneration

Proper scaffolds combined with mesenchymal stem cells (MSCs) represent a promising strategy for repairing bone defects. In a previous study, poly (fumaroyl bioxirane) maleate (PFM), a newly developed functional polymer with numerous functional groups, exhibited excellent biocompatibility and enhanced the alkaline phosphatase (ALP) activity of osteoblasts in vitro. Here, to provide further and comprehensive insight into the application of PFM in bone tissue engineering, we investigated the osteoinductive potential of PFM cultured with rat adipose-derived mesenchymal stem cells (rADSCs). The results showed that PFM resulted in greater proliferation of rADSCs and that the PFM substrate had stronger osteoinductivity than PLGA and the control, as indicated by the significant upregulation of osteogenesis-related genes, proteins and calcium mineralization in vitro. Next, PFM was combined with rADSCs to repair a critical-sized calvarial defect in rats. Compared to the PLGA scaffold, the PFM scaffold significantly promoted new bone formation and exhibited excellent effects in repairing rat calvarial defects. In conclusion, PFM possesses strong osteoinductivity, which could markedly enhance bone regeneration, suggesting that PFM could serve as a promising and effective optimization method for traditional scaffolds in bone regeneration.