Cong Mao

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.

Angiogenesis stimulated by novel nanoscale bioactive glasses

The ability of biomaterials to induce rapid vascular formation is critical in tissue regeneration. Combining recombinant angiogenic growth factors with bioengineered constructs have proven to be difficult due to several issues, including the instability of recombinant proteins, the need for sustained delivery and the dosage of factors. New formulations of bioactive glass, 58S nanosized bioactive glass (58S-NBG), have been reported to enhance wound healing in animal models better than the first generation of 45S5 Bioglass. Therefore, we investigated the effects of extracts of 58S-NBG and 80S-NBG on cultures of human umbilical vein endothelial cells (HUVECs). Cell viability was assessed by MTS assay. In vitro angiogenesis was measured using an ECM gel tube formation assay, and levels of mRNAs for five angiogenic related genes were measured by qRT-PCR. Extracts of 58S-NBG and 80S-NBG stimulated the proliferation of HUVECs, accelerated cell migration, up-regulated expression of the vascular endothelial growth factor, basic fibroblast growth factor, their receptors, and endothelial nitric oxide synthase, resulting in enhanced tube formation in vitro. The enhanced angiogenic response correlated with increased levels of Ca and Si in the extracts of 58S-NBG and 80S-NBG. The ability of 58S-NBG and 80S-NBG to stimulate angiogenesis in vitro provides alternative approaches for stimulating neovascularization of tissue-engineered constructs.

Synthesis of radial mesoporous bioactive glass particles to deliver osteoactivin gene

Mesoporous bioactive glasses (MBGs) can be used as carriers for biomolecule delivery with improved functions. Although there are a great number of studies on drug delivery by MBGs, until now little work has been done to investigate the DNA gene transfection effect of MBGs. In this study, radial mesoporous bioactive glasses (rMBGs) were prepared by sol-gel process combined with a micro-emulsion method. The surface was further modified by amino groups in order to improve its affinity for DNA. Our study showed that rMBGs have good apatite-forming ability and cellular biocompatibility. In addition, rMBGs can enter cells in a time- and dose-dependent manner, and mainly localize in the cytoplasm. Agarose gel electrophoresis demonstrated that pOA-EGFP (containing the osteoactivin and the green fluorescent protein fusion gene) can be completely absorbed and protected from DNase I degradation by the aminated rMBGs. Additionally, the plasmid can be successfully expressed in cells transfected by rMBGs.

Investigation of emulsified, acid and acid-alkali catalyzed mesoporous bioactive glass microspheres for bone regeneration and drug delivery

Acid-catalyzed mesoporous bioactive glass microspheres (MBGMs-A) and acid-alkali co-catalyzed mesoporous bioactive glass microspheres (MBGMs-B) were successfully synthesized via combination of sol-gel and water-in-oil (W/O) micro-emulsion methods. The structural, morphological and textural properties of mesoporous bioactive glass microspheres (MBGMs) were characterized by various techniques. Results show that both MBGMs-A and MBGMs-B exhibit regularly spherical shape but with different internal porous structures, i.e., a dense microstructure for MBGMs-A and internally porous structure for MBGMs-B. (29)Si NMR data reveal that MGBMs have low polymerization degree of silica network. The in vitro bioactivity tests indicate that the apatite formation rate of MBGMs-B was faster than that of MBGMs-A after soaking in simulated body fluid (SBF) solution. Furthermore, the two kinds of MBGMs have similar storage capacity of alendronate (AL), and the release behaviors of AL could be controlled due to their unique porous structure. In conclusion, the microspheres are shown to be promising candidates as bone-related drug carriers and filling materials of composite scaffold for bone repair.

Fabrication and characterization of dodecylamine derived monodispersed mesoporous bioactive glass sub-micron spheres

AbstractnThis paper reports a facile method for fabricating monodispersed mesoporous bioactive glass sub-micron spheres (MBGS) using dodecylamine (DDA) as a catalyst and template agent in sol–gel process. The effects of synthesis conditions including the amount of DDA, temperature of hydrolysis and the volume ratio of alcohol to water (AW ratio) on the resulting particle size, morphology, monodispersity and pore size distribution of MBGS are investigated and discussed. The results indicate that the particle size, morphology, monodispersity and pore size distribution of MBGS depend on the amount of DDA, the temperature of hydrolysis and the AW ratio. Meanwhile, using DDA as the structure directing agent and hydrolysis catalyst under optimal synthesis conditions (e.g. 4xa0g DDA, hydrolysis temperature at 40xa0°C and AW ratio at 4) is in favor of obtaining MBGS with mesoporous surface structure, large specific surface area (362.073xa0m2xa0g−1), relatively homogeneous particle size (~560xa0nm) as well as good apatite-forming activity. The unique structure and properties may turn MBGS into a good candidate as a drug delivery carrier or an injectable biomaterial for bone tissue regeneration.

Synthesis and characterization of europium-containing luminescent bioactive glasses and evaluation of in vitro bioactivity and cytotoxicity

AbstractnLuminescent europium-containing bioactive glasses (EuBG) based on the 58xa0%SiO2–33xa0%CaO–9xa0%P2O5 (in mass, %) system were synthesized using sol–gel technique by adding Eu2O3 in silica network. The structural, textural and optical properties, as well as in vitro bioactivity and biocompatibility of the material were characterized using various methods. The results show that all the Eu-containing bioactive glass materials exhibit an amorphous structure, large specific surface area, relatively uniform pore size distribution and high in vitro bioactivity, similar to the conventional sol–gel bioactive glass. More importantly, the addition of Eu2O3 endow the material with a luminescent property even after immersion in aqueous solution and the luminescent intensity increases with the increase of Eu2O3 content. The cytotoxicity assay indicates that pure EuBG extract significantly inhibit the growth of rat marrow mesenchymal stem cells (rMSCs), while 25xa0% concentration of the extract diluted by culture medium could significantly improve the proliferation of rMSCs in comparison with pure medium. According to the above results, the material presents excellent apatite-forming activity, luminescent property and biocompatibility, demonstrating their potential applications in the fields of bone regeneration and drug delivery system.

Enhanced healing of full-thickness diabetic wounds using bioactive glass and Yunnan baiyao ointments

In order to accelerate the chronic wounds healing, we investigated the healing effects of bioactive glass and Yunnan baiyao ointments in streptozotocin-induced diabetic rats. The ointments were prepared by mixing 45S5 bioactive glass powder (16% weight) with Vaseline and different weight percentages of Yunnan baiyao. Full-thickness defect wounds were created on the back of 130 SD rats and were randomly divided into 8 groups. The wound healing rates were calculated at 4, 7, 10, 14 and 21 days after surgery. The samples were harvested for further observations. Considering the wound closure rate, group 6 (with 5% Yunnan baiyao) has better wound healing performance than other diabetic groups. The lower inflammatory response was observed by gross observation and confirmed by the results of H&E staining and TEM observation. Besides, the proliferation of fibroblasts, the formation of granulation tissue, as well as the vascularization, were improved in group 6 compared to other diabetic groups. All results suggest that bioactive glass and Yunnan baiyao ointments can accelerate the recovery of diabetes-impaired skin wounds, and comparing to other diabetic groups, group 6 (with 5% Yunnan baiyao) has better healing effect.

Acute toxicity and in vivo biodistribution of monodispersed mesoporous bioactive glass spheres in intravenously exposed mice

The use of biomaterials from laboratories to clinics requires exhaustive and elaborate studies involving the biodistribution, clearance, and biocompatibility of biomaterials for in vivo biomedical applications. This study aimed to evaluate the acute toxicity and biodistribution of intravenously administrated sub-micrometer mesoporous bioactive glass spheres (SMBGs) in mice. The lethal dose 50 (LD50) of SMBGs was higher than 250 mg/kg. The acute toxicity was evaluated at 14 days after intravenous injection of SMBGs at 20, 100 and 180 mg/kg in ICR mice. The mortality, coefficients of major organs, hematology data and blood biochemical indexes revealed the low in vivo toxicity of SMBGs at all doses. However, the histological examination showed lymphocytic infiltration and granuloma formation in hepatocyte and megakaryocyte hyperplasia in the spleen at high dose. The silicon content analysis using ICP-OES and TEM results indicated that SMBGs mainly distributed in the resident macrophages of the liver and spleen, and could be cleared from the body more than 2 weeks. These findings can be important for the toxicity assessment of sub-micrometer particles and the development of bioactive glass based drug delivery system for biomedical applications.

A 13-year retrospective study evaluating the efficacy of using air-fluidised beds for toxic epidermal necrolysis patients

Toxic epidermal necrolysis (TEN) is a potentially life‐threatening dermatological disease involving large areas of skin loss with systemic symptoms. This study evaluated the efficacy of air‐fluidised bed therapy for TEN patients.