Nanobioactive Glass Research Articles

Biological Assessment In-Vivo of Gel-HA Scaffold Materials Containing Nano-Bioactive Glass for Tissue Engineering

To evaluate the biological safety of the composite materials based on gelatin (Gel), hyaluronic acid (HA), and nano-bioactive glass (NBG), which has a potential application in tissue engineering, the in-vivo biological properties were investigated by hemolysis behavior, micronucleus, skin irritation and acute toxicity test. Scanning electron microscopy (SEM) morphology demonstrated that the Gel-HA/NBG composite scaffolds had interconnected pores with mean diameters of 50–500 μm. The hemolysis test suggested that the Gel-HA/NBG composite scaffold, with a hemolysis ratio of 1.11%, showed no obvious hemolysis reaction. The micronucleus frequency of the Gel-HA/NBG was (3.1 ± 0.52) %; this indicated that it shows no genotoxic effect. The skin irritation result showed no systemic signs of toxicity in the integrity skin of the animals. The Gel-HA/NBG scaffolds showed no acute systemic toxicity and the liver, heart, lung, and kidney samples also showed no remarkable change in the morphology. Therefore, Gel-HA/NBG composite scaffold would be a suitable candidate of biomedical materials for tissue engineering.

Influences of Molecular Weight and Content of Polyethylene Glycol on Morphology and Size of Nano-Bioactive Glass

Nano-bioactive glass (NBG) was prepared via sol-gel method and freeze-dried technique using polyethylene glycol (PEG) as templates. The influences of molecular weight and content of polyethylene glycol on the morphology and the size NBG particles were investigated. The optimal sintering temperature of NBG was determined by using thermal gravimetric (TG) and differential thermal analysis (DTA), and the NBG particles were characterized by Fourier-transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The XRD pattern of NBG sintered at 650°C in air confirmed that the calcined glass existed in amorphous state. The results indicated that the PEG molecular weight and PEG content have obvious effects on the morphology and size of the NBG particles. The size of NBG particle prepared with PEG-200 was beyond 1μm and the aggregation was obvious. The size of obtained NBG particle with PEG-10000 was between 50 nm and 80 nm, with a hollow spherical shape; while the morphology of the NBG with PEG-20000 was needle-shaped, with an average width of 20 nm and length of 100 nm. The particle size of the NBG particles decreased with the increase of PEG concentration.

Odontogenic differentiation and dentin formation of dental pulp cells under nanobioactive glass induction

Bioactive glass (BG) has been widely used in bone regeneration; however, reports on the biological effects of BG on dental pulp cells are rare. This study aims to investigate the effects of nanoscale BG (n-BG) on odontogenic differentiation and dentin formation of dental pulp cells and to compare these effects with those of microscale BG (m-BG). Human dental pulp cells (hDPCs) from third molars were cultured directly with m-BG and n-BG in vitro. The cell proliferation increased at 0.1mgml−1 BG, which also had a chemotactic effect on hDPCs. The mineralization capacity and expression of odontogenic-related proteins and genes (dentin sialophosphoprotein, dentin matrix protein 1 and collagen type I) of hDPCs were significantly up-regulated under BG induction, and were particularly higher in the n-BG group than in the control group. m-BG and n-BG combined with pulp tissues were transplanted into the dorsum of immunodeficient mice to observe their biological effects on dental pulp cells in vivo. A continuous layer of dentin-like tissue with uniform thickness, a well-organized dentinal tubule structure and polarizing odontoblast-like cells aligned along it was generated upon the n-BG layer, whereas some irregular sporadic osteodentin-like mineralized tissues were observed in the control group. This study reveals that BG, especially n-BG, induces the odontogenic differentiation and dentin formation of dental pulp cells and may serve as a potential material for pulp repair and dentin regeneration.

In vivo cytotoxicity of MgO-doped nanobioactive glass particles and their anticorrosive coating on Ti–6Al–4V and SS304 implants for high load-bearing applications

Magnesium-doped NBG composites (SiO2–CaO–P2O5–MgO) coated implant is found to be a potential nanocomposite for high load-bearing applications with better anticorrosive property and long-term stability.

Synthesis, Characterization and <i>In Vitro</i> Evaluation of Strontium-Containing Sol-Gel Derived Bioactive Glass/ Biphasic Calcium Phosphate Nanocomposite

In the present research, strontium containing nanobioactive glass (NBG-Sr) was synthesized by sol-gel method. The morphology was analyzed by transmission electron microscope (TEM). Different amounts (0.5 to 5 wt%) of NBG-Sr were then added to biphasic calcium phosphate (BCP). They were sintered at different temperatures, i.e., 1100, 1200 and 1300 °C and changes in physical and mechanical properties were investigated. A sharp decrease in pore volume was observed as the temperature increased. The maximum bending strength (~45 MPa) was achieved for BCP which was mixed with 3 wt% NBG-Sr and sintered at 1200 °C. This value was approximately the same when it was sintered at 1300 °C. The bending strength failed when both lower and higher amounts of 3 wt% NBG-Sr were utilized. Therefore, sintering of composites at 1200 °C was economically reasonable. The X-ray results showed that NBG-Sr additive did not change the phase composition of BCP when it was heat treated at 1200 °C. The attachment and proliferation of rat calvarium-derived osteoblasts on samples sintered at 1200 °C were also evaluated by scanning electron microscopy (SEM). Based on cell studies, all NBG-Sr-added BCPs supported attachment and proliferation of osteoblastic cells. Overall, biphasic calcium phosphate materials with improved mechanical and biological properties can be produced by using certain quantity of strontium-containing bioactive glass particles.

Fabrication and characterisation of gelatin-hyaluronic acid/nanobioactive glass hybrid scaffolds for tissue engineering

Nanobioactive glass (NBG) particles were synthesised via sol–gel method and characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The new composite biomaterial based on gelatin (Gel) conjugated with hyaluronic acid (HA) and NBG in the ternary SiO2–CaO–P2O5 system was prepared through freeze drying method. The composite scaffold was characterised by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermal analyses. Mechanical properties and swelling behaviour of this composite are compared with properties of Gel-HA/NBG composite of similar material without NBG. The TEM results indicated that the prepared NBG particle size was ∼100 nm. The SEM studies showed that the NBG were homogenously distributed within the Gel/HA matrix and the composite scaffolds showed interconnected pores with a size varied from 50 to 200 μm. The Gel-HA/NBG composite scaffold showed higher compressive strength and better stability than the Gel/HA scaffold. These results indicate that composite scaffolds developed using NBG disseminated Gel/HA matrix as potential scaffolds for tissue engineering applications.

Mechanical properties and in vitro cellular behavior of zinc-containing nano-bioactive glass doped biphasic calcium phosphate bone substitutes

In the present study, different amounts (0.5-5 wt%) of a sol gel-derived zinc-containing nano-bioactive glass (NBG-Zn) powder were added to biphasic calcium phosphate (BCP). The mixtures were sintered at 1,100-1,300 °C and physical characteristics, mechanical properties, phase composition and morphology of them were studied. The samples were also soaked in human blood plasma for 15 days to evaluate variations in their surface morphologies. Rat calvarium-derived osteoblastic cells were seeded on tops of various samples and cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different culturing periods. The maximum bending strength (62 MPa) was obtained for BCP containing 0.5 wt% NBG-Zn at temperature 1,200 °C. This value was approximately 80% higher than that of pure BCP. The bending strength failed when both sintering temperature and amount of added NBG-Zn increased. At 1,100 °C, NBG-Zn additive did not change the phase composition of BCP. At temperatures 1,200 and 1,300 °C, both alpha-tricalcium calcium phosphate (α-TCP) and beta-tricalcium phosphate (β-TCP and) phases were detected. However, adding higher amount of NBG-Zn to BCP resulted in elevation of β-TCP at 1,200 °C and progression of α-TCP at 1,300 °C. Based on the microscopic observations, adding 0.5 wt% NBG-Zn to BCP led to disappearance of grain boundaries, reduction of micropores and formation of a monolithic microstructure. No calcium phosphate precipitation was observed on sample surfaces after soaking in blood plasma, but some pores were produced by phase dissolution. The size and volume of these pores were directly proportional to NBG-Zn content. Based on the cell studies, both BCP and NBG-Zn-added BCP samples supported attachment and proliferation of osteoblasts, but higher alkaline phosphatase enzyme was synthesized within the cells cultured on NBG-Zn-added BCP. Overall, biphasic calcium phosphate materials with improved mechanical and biological properties can be produced by using small quantity of zinc-containing bioactive glass particles.

Collagen hydrogels incorporated with surface-aminated mesoporous nanobioactive glass: Improvement of physicochemical stability and mechanical properties is effective for hard tissue engineering

Collagen (Col) hydrogels have poor physicochemical and mechanical properties and are susceptible to substantial shrinkage during cell culture, which limits their potential applications in hard tissue engineering. Here, we developed novel nanocomposite hydrogels made of collagen and mesoporous bioactive glass nanoparticles (mBGns) with surface amination, and addressed the effects of mBGn addition (Col:mBG=2:1, 1:1 and 1:2) and its surface amination on the physicochemical and mechanical properties of the hydrogels. The amination of mBGn was shown to enable chemical bonding with collagen molecules. As a result, the nanocomposite hydrogels exhibited a significantly improved physicochemical and mechanical stability. The hydrolytic and enzymatic degradation of the Col–mBGn hydrogels were slowed down due to the incorporation of mBGn and its surface amination. The mechanical properties of the hydrogels, specifically the resistance to loading as well as the stiffness, significantly increased with the addition of mBGn and its aminated form, as assessed by a dynamic mechanical analysis. Mesenchymal stem cells cultivated within the Col–mBGn hydrogels were highly viable, with enhanced cytoskeletal extensions, due to the addition of surface aminated mBGn. While the Col hydrogel showed extensive shrinkage (down to ∼20% of initial size) during a few days of culture, the shrinkage of the mBGn-added hydrogel was substantially reduced, and the aminated mBGn-added hydrogel had no observable shrinkage over 21days. Results demonstrated the effective roles of aminated mBGn in significantly improving the physicochemical and mechanical properties of Col hydrogel, which are ultimately favorable for applications in stem cell culture for bone tissue engineering.

Preparation and Characterization of Silver-Doped Nanobioactive Glass Particles and Their <I>In Vitro</I> Behaviour for Biomedical Applications

In this study, silver-doped silica- and phosphate-based nanobioactive glass compositions (58SiO2-(33- x)CaO-9P2O5-xAg2O) (x = 0, 0.5, 1, 2 and 3 mol%) were synthesised by a simple and cost-effective sol-gel method. The prepared samples were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray fluorescence spectrometer studies. All the compositions of the glass samples revealed amorphous phase with spherical morphology and a particle size less than 100 nm. The prepared glass samples reveal the specific surface area in the range of 55.31-90.69 m2 g(-1). The bioactivity of glass samples was confirmed through the formation of the hydroxyapatite layer on glass surfaces during in vitro studies in which silver doped glasses (2 and 3 mol%) showed better bioactivity. A better biocompatibility was achieved in human gastric adenocarcinoma cell line in case of silver-free glass sample while comparing the biological behaviour of Ag2O-doped glasses. Further, the Ag2O-doped nanobioactive glasses revealed significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Ag2O substitutions showed better in vitro bioactivity and remained slightly toxic to human cells at a concentration of 100 microg mL(-1). Silver-doped nanobioactive glass shows good antimicrobial property as well as no significant toxic for implant applications.

Electrochemical Deposition of 58SiO2‐33CaO‐9P2O5 Nanobioactive Glass Particles on Ti‐6Al‐4V Alloy for Biomedical Applications

The nanobioactive glass (58SiO2‐33CaO‐9P2O5) powders were synthesized by simple sol–gel method. The prepared samples reveal amorphous nature, agglomerated spherical morphology with particle size of 100–150 nm. The specific surface area of nanobioactive glass (NBG) particle is 147 m2/g. The NBG samples were coated on titanium (Ti‐6Al‐4V) alloy through electrochemical deposition method. The particle size of the NBG‐coated surface was in the order of 200–300 nm, and it was confirmed by atomic force microscopy (AFM) analysis. In vitro and AFM studies reveal the existence of higher bioactivity and uniform coating of NBG on implants at 80 V for 1 h.

Biocompatibility In-vitro of Gel/HA Composite Scaffolds Containing Nano-Bioactive Glass for Tissue Engineering

Designing and fabricating nanocomposite scaffolds for bone regeneration from different biodegradable polymers and bioactive materials are an essential step to engineer tissues. In this study, the composite scaffold of gelatin/hyaluronic acid (Gel/HA) containing nano-bioactive glass (NBG) was prepared by using freeze-drying method. The biocompatibilities in-vitro of the Gel-HA/NBG composite scaffolds, including MTT assay, ALP activity, von Kossa staining and tetracycline staining, were investigated. The SEM observations revealed that the prepared scaffolds were porous with three-dimensional (3D) and interconnected microstructure, agglomerated NBG particles were uniformly dispersed in the matrix. MTT results indicated that the tested materials didn't show any cytotoxicity. The presence of NBG in the composite scaffold further enhanced the ALP activity in comparison with the pure Gel/HA scaffold. The von Kossa staining and tetracycline staining results also indicated that the NBG may improve the cell response. Therefore, the results indicated the nanocomposite scaffold made from Gel, HA and NBG particles could be considered as a potential bone tissue engineering implant.

In-Vitro Biocompatibility Evaluation of Collagen-Hyaluronic Acid/Bioactive Glass Nanocomposite Scaffold

A nano-structured scaffold was designed for bone repair using collagen, hyaluronic acid (HYA) and nano-bioactive glass (NBaG) as its main components. The collagen-HYA/NBaG scaffold was prepared by using a freeze-drying technique and characterized by scanning electron microscopy (SEM). Osteoblastls were seeded on these scaffolds and their proliferation rate, alkaline phosphatase (ALP) activity and ability to form mineralized bone nodules were compared with those osteoblasts grown on cell culture plastic surfaces. The cross-section morphology shows that the collagen-HYA/NBaG scaffold possessed a three-dimensional (3D) interconnected homogenous porous structure. The results obtained from biological assessment show that this scaffold did not negatively affect osteoblasts proliferation rate and improves osteoblasts function as shown by increasing the ALP activity and calcium deposition and formation of mineralized bone nodules. Therefore, the composite scaffolds could provide a favorable environment for initial cell adhesion, maintained cell viability and cell proliferation, and had good in-vitro biocompatibility.

Odontogenic responses of human dental pulp cells to collagen/nanobioactive glass nanocomposites

ObjectivesCollagen-based nanocomposite incorporating nanobioactive glass (Col/nBG) was developed as a scaffolding matrix for dentin–pulp regeneration. The effects of the novel matrix on the proliferation of human dental pulp cells (hDPCs) and their differentiation into odontoblastic lineage were investigated. MethodsNanocomposite scaffold was prepared by incorporating nBG within the Col solution and then reconstituting them into a membrane form. Cell growth by MTS assay, adhesion by scanning electron microscopy (SEM), and odontoblastic differentiation by alkaline phosphatase (ALP) activity, mineralization, and the mRNA expression of differentiation-related genes of DPCs on each scaffold were evaluated. ResultsThe introduction of nBG significantly improved the bone mineral-like apatite formation in the simulated body fluid, suggesting excellent acellular bone-bioactivity. The hDPCs cultured on the Col/nBG nanocomposite have shown active growth behavior during culture for 14 days. The mRNA levels of major organic extracellular matrix of dentin, collagen type I and III were highly expressed in the Col/nBG matrix. Moreover, the alkaline phosphatase (ALP) activity and the mineralized nodule formation were increased in the Col/nBG nanocomposite compared to those in Col. Odontoblatic differentiation genes, including dentin sialophosphoprotein, dentin matrix protein I, ALP, osteopontin and osteocalcin were significantly stimulated in the Col containing nBG. Moreover, the key adhesion receptor integrin components α2 and β1, specifically binding to collagen molecule sequence, were upregulated in Col/nBG compared to Col, suggesting that odontogenic stimulation was closely related to the integrin-mediated process. SignificanceIn our study, the nanocomposite Col/nBG matrix induced the growth and odontogenic differentiation more effectively than Col alone, providing a promising scaffold condition for regeneration of dentin–pulp complex tissue.

Synthesis, characterization and biological response of magnesium-substituted nanobioactive glass particles for biomedical applications

In this study, silica-based magnesium-substituted nanobioactive glass compositions (58SiO2–33CaO–9P2O5, 58SiO2–23CaO–9P2O5–10MgO and 58SiO2–13CaO–9P2O5–20MgO (mol %)) were synthesized by a simple, cost-effective sol–gel method. The synthesized nanobioactive glass samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray fluorescence spectrometer studies. The prepared samples revealed amorphous phase with spherical morphology, having a particle size less than 50nm. The samples MT0, MT10 and MT20 showed average pore diameters of 18.67, 17.35 and 24.51nm while the specific surface areas were 90.69, 95.56 and 86.70m2g−1, respectively. The bioactivity of glass samples was confirmed by the formation of hydroxyapatite layer on glass surfaces during in vitro studies. Further, the MgO-doped nanobioactive glasses did not reveal significant antibacterial activity. A better biocompatibility was achieved in human gastric adenocarcinoma cell line in case of MgO glass samples while comparing the biological behaviour of MgO-based glasses with base glass. MgO substitutions show better in vitro bioactivity and remain non-cytotoxic to human cells.

Mechanical and In Vitro Biological Properties of Hydroxyapatite Bioceramics Reinforced with Strontium-Containing Nano-Bioactive Glass

In this study, different amounts of sol-gel derived strontium-containing bioactive glass nano-powders were added to hy- droxyapatite to improve its mechanical properties. The bodies were sintered at 1000-1200 °C. Strontium was used in the bioglass compo- sition for its stimulating effects on bone formation. XRD, SEM and microindentation methods were employed for phase analysis, micro- structure observation and microhardness/toughness measurements, respectively. Proliferation and activity of rat-derived osteoblastic cells on samples were also determined using MTT and alkaline phosphatase assays. The results showed that the phase composition of pure hy- droxyapatite was not affected by elevating temperature; however, the addition of 1-10% of bioactive glass nano-powder to hydroxyapa- tite led to the formation of � -TCP phase in which its content increased with bioglass concentration and temperature. In addition to � - TCP, �-TCP and calcium phosphate s ilicate were also found in the composition of hydroxyapatite sintered with 10% bioglass. Bending strength, microhardness and fracture toughness were improved by adding 1-5% bioglass to hydroxyapatite, whereas a decrease in these mechanical properties was observed by adding 10% bioglass. According to the results, the addition of nano-sized bioglass did not change the rate of cell proliferation, but increased the level of alkaline phosphatase produced.

Healing effect of bioactive glass ointment on full-thickness skin wounds

This study aimed to investigate the effect of bioactive glasses on cutaneous wound healing in both normal rats and streptozotocin-induced diabetic rats. Bioactive glass ointments, prepared by mixing the sol–gel bioactive glass 58S (SGBG-58S), nanobioactive glass (NBG-58S) and the melt-derived 45S5 bioactive glass (45S5) powder with Vaseline (V) at 18% weight percentage, were used to heal full thickness excision wounds. Pure V was used as control in this study. Compared to SGBG-58S, NBG-58S consists of relatively dispersible nanoparticles with smaller size. The analysis of wound healing rate and wound healing time showed that bioactive glasses promoted wound healing. The ointments containing SGBG-58S and NBG-58S healed the wounds more quickly and efficiently than the ointment containing 45S5. Histological examination indicated that bioactive glasses promoted the proliferation of fibroblasts and growth of granulation tissue. Immunohistochemical staining showed that the production of two growth factors, VEGF and FGF2, which are beneficial to wound healing, was also stimulated during the healing process. Transmission electron microscope observations showed that fibroblasts in wounds treated with bioactive glasses contained more rough endoplasmic reticula and had formed new capillary microvessels by the seventh day. The effects of SGBG-58S and NBG-58S were better than those of 45S5. All results suggest that bioactive glasses, especially SGBG-58S and NBG-58S, can accelerate the recovery of skin wounds in both normal and diabetes-impaired healing models and have a great potential for use in wound repair in the future.

Fabrication and characterization of silk fibroin/bioactive glass composite films

Composite films of silk fibroin (SF) with nano bioactive glass (NBG) were prepared by the solvent casting method, and the structures and properties of the composite films were characterized. Fourier transform infrared (FT-IR) spectroscopy analysis shows that the random coil and β-sheet structure co-exist in the SF films. Results of field emission scanning electron microscope (FESEM) indicate that the NBG particles are uniformly dispersed in the SF films. The measurements of the water contact angles suggest that the incorporation of NBG into SF can improve the hydrophilicity of the composites. The bioactivity of the composite films was evaluated by soaking in 1.5 times simulated body fluid (1.5× SBF), and formation of a hydroxycarbonate apatite (HCA) layer was determined by XRD and FESEM. The results show that the SF/NBG composite film is bioactive as it induces the formation of HCA on the surface of the composite film after soaking in 1.5× SBF for 7days. In vitro osteoblasts attachment and proliferation tests show that the composite film is a good matrix for the growth of osteoblasts. Consequently, the incorporation of NBG into the SF film can enhance both the bioactivity and biocompatibility of the film, which suggests that the SF/NBG composite film may be a potential biomaterial for bone tissue engineering.

Robocasting chitosan/nanobioactive glass dual-pore structured scaffolds for bone engineering

Here we produced a novel nano-composite scaffold made of chitosan (Chit) and nanobioactive glass (nBG) retaining dual-pore structure through the robocasting technique. Robotic-dispensed composite solution (Chit with 10wt% nBG) was rapidly solidified under a dry-ice cooled bath, which was subsequently freeze-dried. The scaffold featured the pre-designed macrochanneled (hundreds of micrometers) pore configuration and contained well-developed micropores (a few to 10μm in size) throughout the framework. The addition of nBG facilitated rapid induction of bone mineral-like apatite in a simulated body fluid, demonstrating in vitro bone-bioactivity. On the dual-pore structured scaffolds, bone cells presented good adherence and active growth with culture time. The developed Chit/nBG scaffolds may find potential usefulness as bone tissue engineering matrices.

Genotoxicity effects of nano bioactive glass and Novabone bioglass on gingival fibroblasts using single cell gel electrophoresis (comet assay): An in vitro study

Genotoxicity effects of nano bioactive glass and Novabone bioglass on gingival fibroblasts using single cell gel electrophoresis (comet assay): An in vitro study

Chitosan–nanobioactive glass electrophoretic coatings with bone regenerative and drug delivering potential

Nanocomposites with bone-bioactivity and drug eluting capacity are considered as potentially valuable coating materials for metallic bone implants. Here, we developed composite coatings of chitosan (CH)–bioactive glass nanoparticles (BGn) via cathodic electrophoretic deposition (EPD). BGn 50–100 nm in size with aminated surface were suspended with CH molecules at different ratios (5–20 wt% BGn) in aqueous medium, and EPD was performed. Uniform coatings with thicknesses of a few to tens of micrometers were produced, which was controllable by the EPD parameters (voltage, pH and time). Thermogravimetric analysis revealed the quantity of BGn within the coatings that well corresponded to that initially incorporated. Apatite forming ability of the coatings, performed in simulated body fluid, was significantly improved by the addition of BGn. Degradation of the coatings increased with increasing BGn addition. Of note, the degradation profile was almost linear with time; degradation of 5–13 wt% during 1 week became 30–40 wt% after 7 weeks at almost a constant rate. The CH–BGn coatings showed favorable cell adhesion and growth, and stimulated osteogenic differentiation. Drug loading and release capacity of the CH–BGn coatings were performed using the ampicillin antibiotic as a model drug. Ampicillin, initially incorporated within the CH–BGn suspension, was eluted from the coatings continuously over 10–11 weeks, confirming long-term drug delivering capacity. Antibacterial tests also confirmed the effects of released ampicillin using agar diffusion assay against Streptococcus mutants. The CH–BGn may be potentially useful as a coating composition for metallic implants due to the excellent bone bioactivity and cell responses, as well as the capacity for long-term drug delivery.