Dissertations / Theses on the topic 'Mesoporous bioactive glasse'

Bone defects, especially large bone defects, remain a major challenge in orthopaedic surgery. Autologous bone transplantation is considered the most effective treatment, but insufficient donor tissue, coupled with concerns about donor site morbidity, has hindered this approach in large-scale applications. Alternative approaches include implanting biomaterials such as bioactive glass (BG), which has been widely used for bone defect healing, due to having generally good biocompatibility, and can be gradually biodegraded during the process of new bone formation. Mesoporous bioactive glass (MBG) is a newly developed bioactive glass which has been proven to have enhanced in-vitro bioactivity; however the in-vivo osteogenesis has not been studied. A critical problem in using the bone tissue engineering approach to restore large bone defects is that the nutrient supply and cell viability at the centre of the scaffold is severely hampered since the diffusion distance of nutrients and oxygen for cell survival is limited to 150-200µm. Cobalt ions has been shown to mimic hypoxia, which plays a pivotal role in coupling angiogenesis with osteogenesis in-vivo by activating hypoxia inducing factor-1α (HIF-1α) transcription factor, subsequently initiating the expression of genes associated with tissue regeneration. Therefore, one aim of this study is to investigate the in-vivo osteogenesis of MBG by comparison with BG and β-TCP, which are widely used clinically. The other aim is to explore hypoxia-mimicking biomaterials by incorporating Cobalt into MBG and β-TCP. MBG and β-TCP incorporated with 5% cobalt (5Co-MBG and 5CCP) have also been studied in-vivo to determine whether the hypoxic effect has a beneficial effect on the bone formation. The composition and microstructure of synthesised materials (BG, MBG, 5Co-MBG, 5CCP) were characterised, along with the mesopore properties of the MBG materials. Dissolution and cytotoxicity of the Co-containing materials were also investigated. Femoral samples with defects harvested at 4 and 8 weeks were scanned using micro-CT followed by processing for histology (H&E staining) to determine bone formation. Histology of MBG showed a slower rate of bone formation at 4 weeks than BG, however at 8 weeks it could be clearly seen that MBG had more bone formation. The in-vivo results show that the osteogenesis of MBG reciprocates the enhanced performance shown in-vitro compared to BG. Dissolution study showed that Co ions can be efficiently released from MBG and β-TCP in a controllable way. Low amounts of Co incorporated into the MBG and β-TCP showed no significant cytotoxicity and the Co-MBG powders maintained a mesopore structure although not as highly ordered as pure MBG. Preliminary study has shown that Co incorporated samples showed little to no bone formation, instead incurring high lymphocyte activity. Further studies need to be done on Co incorporated materials to determine the cause for high lymphocyte activity in-vivo, which appear to hinder bone formation. In conclusion, this study demonstrated the osteogenic activity of MBG and provided some valuable information of tissue reaction to Co-incorporated MBG and TCP materials.

Sol-gel derived, silica-based bioactive glasses of a ternary system (SiO₂ – CaO – P₂O₅) has the potential to promote hard and soft tissue regeneration. Compared to melt-derived glasses, glasses synthesised from the sol-gel process has the advantage of low processing temperatures, high specific surface areas (SSA) and tailorable porous nanostructures. Using scaffolds as a strategy for tissue engineering, the application of sol-gel derived bioactive glasses in combination with alginate polymers as scaffold composite materials has great potential and therefore requires further study. This thesis investigates the synthesis of bioactive glasses via the sol-gel (acidic) route and the multi-step (alkali) route, through the sol → drying → sintering stages. Sol-gel route nanoparticles derived were heterogeneous in shape, while the multi-step route produced spherical (30 – 90 nm diameter) nanoparticles. Increases in calcium content of the sol led to an increase in pore size and a decrease in SSA. Three dehydration methods: oven, vacuum and freeze drying were devised to control the morphology of nanoparticles. Freeze dried nanoparticles were found to have a rough surface texture, with an aligned ordered porous nanostructure. This led to faster apatite formation when compared to oven dried nanoparticles immersed in simulated body fluid (SBF). A novel internal ionic diffusion cross-linking method of alginate was developed, utilising the glass nanoparticles as nanocarriers, for the synthesis of alginate-bioactive glass composite scaffolds. Strontium chloride (SrCl₂) and copper chloride (CuCl₂), which provided therapeutic ions, were impregnated into the nanocarriers, and were compared to calcium chloride (CaCl₂), as the control. Impregnation efficiency was in the order of CuCl₂ > SrCl₂ ≈ CaCl₂, attributed to Cu²⁺ having the smallest ionic radii and its interaction with silinol groups on the nanocarrier surfaces. Scaffold gelation time was correlated to the type of cross-linking salt, its loading concentration and glass to alginate (G/A) ratio. It was observed that SrCl₂ loaded nanocarriers (BGSr) were most efficient in cross-linking when compared to CuCl₂ and CaCl₂ loaded nanocarriers (BGCu and BGCa respectively), due to Sr²⁺ having a greater affinity towards alginate. Results showed that nanocarriers with the highest SSA possessed the highest impregnation efficiency; however nanocarriers with the largest pore diameter and volume led to the fastest scaffold gelation time. BGCa and BGSr scaffolds showed significant improvements in maintaining stiffness (Young’s modulus) and shear resistance (maximum shear stress) after incubation in aqueous solutions for up to 28 days, which were in contrast to the deterioration in mechanical properties of conventional CaCl₂ cross-linked scaffolds. Calcium ions were detected in the range above 260 ppm in BGCa nanocarrier supernatant, suggesting the gradual release of ions from the nanocarriers, internally diffusing into the scaffold matrix, leading to continuous cross-linking over time. Meanwhile, in vitro biological studies showed fast apatite formation on BGCa cross-linked scaffolds in SBF, with the scaffolds capable of supporting the attachment, growth and proliferation of human osteoblast cells, thus indicating their high bioactivity. Control over glass nanoparticle morphology was achieved and through specific ionic impregnation, the successful synthesis of alginate-bioactive glass composite scaffolds was demonstrated, producing bioactive scaffolds with improved mechanical properties.

Améliorer la stabilité de l’interface dentine adhésif est primordial si on veut prolonger la durée de vie et la longévité des restaurations en composite. La reminéralisation utilisant des matériaux relarguant des ions semble etre une approche prometteuse pour protéger la couche hybride de la dégradation hydrolytique et enzymatique. Les verres bioactifs mésoporeux (MBG) présentent des caractéristiques de surface intéressantes qui permettent de les utiliser comme charges au sein de l’adhésif qui favorisent d’une part la reminéralisation par la libération d’ions, d’autre part la fonctionnalisation des pores par des médicaments antibactériens. Ces caractéristiques permettent de lutter contre la reprise de carie. Le présent travail porte sur la synthèse et l'évaluation de nouveaux MBG pouvant être utilisés comme charges dans les adhésifs dentaires. Les MBG ont été préparés dans un système sol-gel à base d'acétate avec des précurseurs industriellement sûrs et non toxiques. Les MBG préparés à grande échelle (50g) offrent des caractéristiques de surface améliorées par rapport aux MBG à petite échelle (10g). L'étude de l'influence des modificateurs de réseau (CaO: Na2O) sur les caractéristiques de surface des MBG a révélé que la porosité était influencée par la teneur en CaO dans la composition. Une surface spécifique très élevée (535 m2g-1) et un volume de pores (0,33 cm3) ont été atteints dans le MBG avec la plus forte teneur en CaO. Par la suite, l'ordre de l'effet d'addition des précurseurs sur les caractéristiques de surface des MBG a été étudié. En maintenant la composition fixée et en faisant varier l'ordre d'addition du précurseur pendant la synthèse sol-gel, on a obtenu une augmentation de 1,5 fois du volume des pores et une diminution de 1,2 fois de la taille moyenne des pores. La méthode démontrée est une voie simple et directe pour améliorer la porosité et l'homogénéité des MBG. De plus, la modulation de la taille moyenne des pores pour une composition fixe est également utile pour une éventuelle application d’administration de médicament. En ce qui concerne la bioactivité, les charges de MBG ayant la plus forte teneur en CaO ont augmenté le précipité de phosphate de calcium dans le SBF après 7 jours, par opposition au MBG avec une teneur élevée en Na2O. De plus, tous les échantillons testés étaient non cytotoxiques pour les fibroblastes gingivaux humains (HGF) in vitro. De manière positive, les MBG traités à basse température ont significativement augmenté l'activité métabolique des HGF. Le broyage à boulets a été utilisé pour réduire la taille des particules primaires de MBG à moins de 3 µm. Le fraisage a visiblement eu un effet néfaste sur la porosité des charges MBG. Néanmoins, une certaine porosité est restée. L'adhésif commercial a été mélangé avec 3, 10, 20 et 30% en poids de charge MBG. L'adhésif rempli de MBG jusqu'à 10% en poids de charge a une viscosité fluide compatible avec l’application d'un adhésif. Le MBG ainsi développé avec une haute porosité et un contenu en CaO représentent des charges prometteuses pour des futures applications en dentisterie restaurative et régénérative
Improving the stability of adhesive dentin interface is crucial to extend the longevity of composite restorations. Remineralization through use of ion releasing materials is a promising approach to protect the hybrid layer from hydrolytic and enzymatic degradation. Mesoporous bioactive glasses (MBGs) offer attractive surface features (enhanced surface area and porosity) to use them as fillers in dental adhesives to promote remineralization through ions release. Moreover, the functionalization of pores with antibacterial drugs is a good way to combat secondary caries. The present work focused on the synthesis and evaluation of novel MBGs suitable to be used as fillers in dental adhesives. The MBGs were prepared in an acetate based sol-gel system with industrially safe and non-toxic precursors. MBGs prepared in large scale (50g) offered enhanced surface characteristics in comparison to small scale (10g) MBGs. The investigation on the influence of network modifiers (CaO:Na2O) on the surface characteristics of MBGs revealed that the porosity was driven by CaO content in the composition. Notable, very high surface area (535m2g-1) and pore volume (0.33cm3g-1) was attained in the MBG with highest CaO content. Next, the order of precursor addition effect on the surface characteristics of MBGs has been studied. By Keeping the composition fixed and varying the order of precursor addition during sol-gel synthesis a doubling of surface area, 1.5 times increase in pore volume and 1.2 times decrease in mean pore size was obtained. The demonstrated method is a simple and straightforward route to improve the porosity and homogeneity of MBGs. Furthermore, modulation of mean pore size for a fixed composition is also useful to tailor the pores of the fillers for drug delivery application. With regards to bioactivity, the MBG fillers with highest CaO content had increased calcium phosphate precipitate in SBF after 7 days as opposed to MBG with high Na2O content. Furthermore, all tested samples were non-cytotoxic to Human Gingival Fibroblasts (HGFs) in vitro. Positively, MBGs treated at lower temperature significantly enhanced the metabolic activity of HGFs. Ball milling was employed to reduce the primary particle size of MBG to less than 3μm. Milling seemingly had an adverse effect on the porosity of the MBG filler. Nevertheless, some porosity remained. The commercial adhesive was mixed with 3, 10, 20 and 30 weight percentage of MBG filler. MBG filled adhesive up to10 weight percent filler content had flowable viscosity suitable for adhesive application. The developed MBG with high porosity and CaO content appears as a new step in the development of dental adhesives and also other bioactive dental materials

碩士
國立臺灣海洋大學
生物科技研究所
99
Polycaprolactone (PCL) is a biodegradable polymer, and it has recently attracted much interest because of its cost efficiency and high toughness as bone tissue engineering scaffold. However, it lacks hydrophilicity and bioactivity. Mesoporous bioactive glass (MBG) has been used for bone tissue engineering due to their reported superior bone-forming bioactivity. The electrospinning technique is a convenient method for production of ultra-thin fibers with diameters ranging from submicrons to a few nanometers. In this study, we utilized an electrospinning fabrication process for the production of nanofibrous matrix that is composed of PCL and MBG. The mean diameter of the composite nanofibrous matrix was approximately 300 nm, this dimension is similar to that of native fibrous protein within the extracellular matrix (ECM). Moreover, we explored the effects of MBG on the hydrophilicity, mechanical strength, bioactivity and cellular response. From the data, MBG/PCL nanofiberous matrix exhibited a significantly improved surface hydrophilicity compared to PCL nanofibrous matrix. The bone-forming bioactivity of matrix was evaluated by soaking the matrix in a simulated body fluid. We could find the MBG/PCL nanofibrous matrix induced a layer of hydroxyapatite in a simulated body fluid at 7 days. The hydroxyapatite crystals were similar in composition to human bone mineral via SEM, X-ray diffraction, EDX analysis and ATR-FTIR. Finally, The cellular attachment rate, proliferation, differentiation and mineralization activity of MG63 osteoblast-like cells were significantly higher for MBG/PCL nanofibrous matrix than for PCL nanofibrous matrix. In addition, with regard to the osteoblast gene and protein ability, we observed that Real-time PCR and western blotting of MG63 cells on the MBG/PCL nanofibrous matrix higher than on the PCL nanofibrous matrix. This indicated that MBG/PCL nanofibrous matrix could potentially be used as a bone graft for bone regeneration.

碩士
國立臺灣科技大學
材料科學與工程系
103
Spray pyrolysis has been successfully used to synthesize mesoporous bioactive glasses (MBGs) with different compositions of SiO2-CaO-P2O5. In this study, the degradability and bioactivity of 58S, 68S and 76S MBG samples were studied. Simulated body fluid (SBF) solution was used as a medium to conduct the degradation test and also bioactivity for 30 days. The weight loss of MBG bulks were measured every day during the in-vitro degradation test. The pH value changes in SBF solution was also monitored every day in order to know the reaction that may occur in SBF solution. Some characterization methods, including x-ray diffraction analysis (XRD), fourier transform infrared (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) have been used to know the phase changes, chemical bonding, surface morphology and compositional analysis respectively. In this research, the effect of composition on the degradation behavior and bioactivity were discussed. Since the degradation behavior of MBG was correlated to the apatite conversion. Furthermore, the mechanism of biodegradability on MBG to apatite conversion was also investigated. 58S MBG had the high degradation rate followed by 68S and 76S respectively. 68S and 76S MBG had ability to form apatite phase with 1 day of immersion while 58S MBG required 3 days of immersion.

碩士
高雄醫學大學
香粧品學系碩士班
99
Mesoporous bioactive glasses scaffold (MBGs) possess a high specific surface area, and exhibits macropores (about 200−400 μm) and mesopores (2-50 nm) structures. Pore wall functionalized and enhancing bone-regenerative ability are the other advantages of MBGs. For these reasons, MBGs is considered to be a candidate for two main uses, bone tissue engineering and drug controlled delivery system. The purpose of this study is to confirm bioactivity of MBGs by in vitro tests and also as a gentamicin carrier to control drug release. MBGs had been constructed by N2 adsorption/desorption and transmission electron microscope exhibits… a large specific surface area ( 328 m2/g ), pore volume ( 0.71 cm3/g ) and a uniformly distributed pore size ( 7.3 nm ), For comparison, in vitro tests results strongly suggest that MBGs is noncytotoxic, better cell affinity than non-mesoporous bioactive glasses scaffold (BGs) and can help cells division and differentiation. The loading content and drug loading efficiency of MBGs are significant than BGs, and the values are 19.2 mg/g and 31.1%. It also been suggested the release rate of MBGs is much slower than BGs. Loading efficiency and content are depends of of initial concentration. The largest amount of drug adsorption was 39.9 mg/g. The release curve exhibits a two- step release behavior, and fit Higuchi model. It also indicates that gentamicin burst-releases initially for a duration of 24 hrs, and then constantly slows released.

碩士
高雄醫學大學
香粧品學系碩士班
101
Root canal therapy is an important procedure in endodontic treatment. The current temporary dressing, calcium hydroxide, may fail to eliminate certain facultative bacteria found in the system, which might cause treatment failure. In this study, we synthesis silver-incorporated mesoporous bioactive glass (MBG-Ag). Hoping to combine the biocompatibility and bioactive of bioactive glass and releasable silver ion. Nitrogen Adsorption/Desorption Isotherm, Transmission Electron Microscopy, Scanning Electron Microscopy, X-ray Diffraction and Fourier transform infrared spectroscopy are used to analyze MBG-Ag. The results indicate that incorporating high content of silver will tend to form ball-shape particles, and the mesopore structure (6-7 nm) won’t be affected. The time-dependent and content-dependent antibacterial activity of MBG-Ag is evaluated by using E. coli. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) is 0.75 mg/ml and 1 mg/ml for E. coli, 0.5 mg/ml and 2.5 mg/ml for E. faecalis, respectively. And for the golden standard of temporary dressing, calcium hydroxide, the MIC against E. faecalis is 5 mg/ml. The silver in MBG-Ag is releasable and causing the antibacterial activity after one hour exposure.

碩士
國立臺灣科技大學
材料科學與工程系
106
The occurrence of the open fractures is often accompanied by complex treatment procedures. In the early stages of treatment for the open fracture, antibiotics are often required to prevent the risk of infection. In addition, in order to achieve an effective therapeutic effect, antibiotics require regular quantitative implantation for the human body. The application of the drug carrier can effectively control the release of the drug and also reduce the number of times to implant the drug into the human body. In the bone fractures of the elderly, the skeletal reparability of the elderly is relatively poor. Bioactive glass is a potential biomaterial for bone implants and drug carriers because it has excellent bioactivity and forms a hydroxyl apatite (HA) layer when immersed in body fluid. In the research of drug carriers, increasing the specific surface area and pore volume can effectively affect the drug loading of the material. One product of these studies is mesoporous bioactive glass (MBG), which has a high specific surface. The common pore-forming agents of MBG are surfactants; however, surfactants present the serious problems of micelle aggregation and carbon contamination. To overcome these problems, hydrogen peroxide (H2O2) has been used as a pore-forming agent to replace the traditional surfactants, such as P123, and F127. In this study, 0, 25, 40, 50, and 69 vol% H2O2-treated MBG powders were synthesized using spray pyrolysis (SP). The corresponding formation mechanisms are also discussed. The results shows that samples with high specific surface area and high pore size have higher drug release.

碩士
國立臺灣科技大學
材料科學與工程系
102
The discovery of bioactive glass by Hench in 1971 has attracted many researchers due to it bioactive property. Bioactive glass elicits biological response from the body that generate mechanically strong biochemical bond, hydroxyl apatite (HA), between implant, bioactive glass, with the host tissue when implanted in human body. This feature of bioactive glass makes it suitable for dental implant, bone filling and many other applications. Since the rate of HA formation is one of its important parameters modifications on morphology have been conducted by many researchers such as increasing the surface area. One of popular approach to increase the surface area is using surfactant as template to generate mesoporous structure in bioactive glass (mesoporous bioactive glass). Spray pyrolysis method has been used to synthesize MBG on previous studies as response to the disadvantage of using sol-gel method to synthesize MBG. However, synthesizing using spray pyrolysis still required many efforts to optimize the MBG produced. To optimize the MBG produced by the spray pyrolysis, various types and concentrations of surfactant are used. Surfactant Pluronic F68, P123 and F127 using various concentrations (14, 31, 44, 53 wt%) are used to investigate its effect on MBG and to study which surfactant and concentration of surfactant has the best bioactive property. MBGs synthesized by using different types and concentrations of surfactant are characterized its crystal structure, morphology, surface area and chemical composition and then studied the effect on it with the increasing concentration and using different type of surfactant. MBGs using different types and concentrations of surfactant also undergo bioactivity test by immersion in SBF (Simulated Body Fluid) and characterized to study the influence of each types and concentrations of surfactant and then compared. The comparison is to determine the most suitable types and concentration of surfactant that gives MBG with the best bioactivity.

碩士
國立臺灣海洋大學
生命科學暨生物科技學系
103
Mesoporous Bioactive glass (MBG) has greater surface area and pore volume than conventional bioactive glass. Hence, MBG is useful as a drug delivery carrier. In the past, MBG was fabricated as dense or porous block. Compared with block, bead has greater flexibility for filling different-shaped cavities with closer packing than nonspherical. Moreover, fibrous material has proved to increase cell attachment and differentiation due to its mimic three-dimensional structure of nature extracellular matrix (ECM). Macroporous material possesses the porous structure of interconnecting channels to allow invasive growth of cells and capillaries. Hence, the aim of this study was to fabricate the macro-mesoporous bioactive glass nanofiber microspheres (MMBGM). In this study, we used electrospinning process to fabricate MBG nanofiber (MBGNF). Then mixed MBGNF with alginate and sprayed into the calcium chloride solution. We also added poly(methyl methacrylate) (PMMA) microspheres as the macropore template in the process, and then removed PMMA microspheres after calcination treatment. The image of scanning electron microscopy showed multiple pores on the surface of MMBGM and the micro computed tomography image also indicated the pore is all over the whole microspheres. The cellular attachment of MG63 osteoblast-like cells was significantly higher for MMBGM than for glass beads after culturing for 4 hours. However, the cell viability significantly decreased after culturing for 1day. We speculated the releasing of high concentration of calcium ion from the MMBGM to decrease cell viability. In order to improve the cell viability, we modified the MMBGM by immersing MMBGM into the simulated body fluid to fabricate a slight apatite layer on the surface of MMBGM. Modified MMBGM indeed could decrease the calcium ions release and improve the cell viability. In vivo, we created a 6 mm bone defect cavity on the condyle of the femoral bone of New Zealand white rabbit and fully filled MMBGM into the cavity. After two months, the rabbits was sacrificed and the femoral bone was take out. Through CT image, the bone defect of control group was rarely recovered. Opposite to the control group, the position within MMBGM was almost filled with new bone. The results showed our MMBGM had great potential in osteogenesis for bone tissue engineering.

碩士
國立屏東科技大學
機械工程系所
98
In order to improve the biocompatibility between the implant and the bone tissue, a biologically active hydroxyapatite layer is formed at the implant-tissue interface. The deposition rate and performance of the hydroxyapatite layer was dependent on the structure of bioglass. Mesoporous bioglasses materials have received much interest because of their high specific surface area and pore volume, and exhibit better in vitro bone forming bioactivity compared to conventional bioglasses. In this study, mesoporous CaO-B2O3-SiO2 bioactive glass with high specific surface area was prepared by sol-gel process and the synthesis was accomplished by using nonionic surfactant (block copolymer) as the template, tetraethyl orthosilicate, calcium nitrate tetrahydrate and tributyl borate as the inorganic precursors. TGA, XRD, TEM and N2 adsorption-desorption isotherms were used to characterize the microstructure of the samples. TGA analysis showed that the calcination in air at temperature above 400℃ was needed to remove the surfactant completely from the mesopores. A broad band between 20 and 30o can be clearly noted in XRD pattern of mesoporous bioactive glass. It can be seen that after being calcined at 400～700℃ for 3 h the sample almost has an amorphous state, which is indicative of the internal disorder and glassy nature of this material. By the nitrogen absorption / desorption analysis found that the calcination temperature 600 ºC, Ca/B ratio of 2:2, the use of triblock copolymer synthesis of mesoporous bioactive glass was informed that the average diameter of 62.48 Å, specific surface area of 231.52 m2/g. The results reveales that a hydroxyapatite layer started to form on the surface in 4 hr after mesoporous CaO-B2O3-SiO2 mesoporous bioactive glass was immersing in simulated body fluid.

碩士
高雄醫學大學
香粧品學系碩士班
100
In recent studies, sealing of exposed dentinal tubules is generally considered as one of effective strategy to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG) is a potential material for treating dentin hypersensitivity due to its excellent biocompatibility and osteoconductivity. In this study, MBG powder preparation by sol-gel method mixed with different calculate ratio of phosphoric acid (PA) was applied on the dentin specimen. We used X-Ray Diffractometer (XRD), Scanning electronic microscope (SEM), and Fourier Transform Infrared (FTIR) to investigate the crystallite phase and surface topography of MBG agents, the occlusion ability of dentinal tubules, and the interatomic bonding. The results showed that the major crystallite phase of MBG agents was monocalcium phosphate monohydrate (Ca(H2PO4)2•H2O). MBG paste, mixed from 30% and 40% PA, had the ability to create the penetrate depth greater than 80 µm. These results showed that MBG paste mixed with phosphoric acid solution have a great ability for occluding dentinal tubules; it has short reaction time and good operability, and these agents have potential for the treatment of dentin hypersensitivity.

碩士
逢甲大學
材料科學與工程學系
106
Bioactive glass (BG) is a kind of artificial biomaterial with high biocompatibility. Recently, Si-Ca-P ternary system, the most common BG component, has been widely used in biomedical-related fields. Mesoporous Bioactive glass (MBG) possessing a high specific surface area and exhibits a better bioactivity than BG. Therefore, MBG is currently gaining popularity in the biomaterial field. The commonly used methods for the preparation of MBG are sol-gel and spray pyrolysis processes. Compared with the sol-gel methods, spray pyrolysis has the important advantages of rapid production and better bioactivity. Currently, the surfactants used in the preparation of MBG for the pore formation are copolymers like P123 and F127. Therefore, it is difficult to discuss the structural changes caused by a single component such as PEG. In addition, the previous research has reported that changing the hydrolysis catalyst acetic acid can increase bioactivity. In this study, tetraethoxysilane (TEOS), calcium nitrate (CN), and triethyl phosphate (TEP) were used as precursors and highly biocompatible polyethylene glycol (PEG) was added as a pore-forming agent during spray pyrolysis. The effects of the surfactant and acetic acid on the structureal characteristics of MBG were investigated by XRD, SEM, TEM, TGA and bioactivity analyses. On the other hand, in order to repair the large defects, a technology called tissue engineering (TE) is further developed. When an artificial scaffold is implanted into the human bodies, the cells grow up along the structure. However, the disadvantage of the MBG scaffolds. is brittle. In a tissue engineering perspective, in order to make MBG scaffolds more suitable to be bioscaffold and to provide good biological activity to facilitate repair of larger defects, spray pyrolyzed MBG particle was synthesized to be a MBG@PMMA core-shell structured powders by seed polymerization. Finally, MBG composite fiber scaffolds were prepared by electrospinning. According to the tensile strength and in-vitro bioanalysis, the MBG composite fiber scaffold we prepared not only possesses an in-vitro bioactivity, but also exhibits well tensile strength of 21 MPa, which makes it more suitable as an implant for tissue engineering.

碩士
高雄醫學大學
藥學研究所
99
Ordered mesoporous bioactive glasses (MBGs) have been successfully synthesized and used in drug delivery systems. They were characterized by nitrogen adsorption/desorption isotherms, TEM, SEM, and FT-IR techniques. They possess characteristics such as tunable and uniform pore size, large surface area, and high pore volume, which make it possible for them to adsorb drug molecules and release them from the meso-structured matrices at a controlled rate. In vitro release, nifedipine, a poorly water-soluble drug, was used as a model drug. Paddle apparatus was applied for the dissolution test at pH 1.2 and 6.8. Both of MBG and N-MBG showed slower releasing at pH 1.2 compared to the nifedipine powder. At pH 6.8, the dissolution profile of N-MBG can be described using zero order kinetic model. Overall, the MBGs can be useful as a drug delivery system due to its controlled release and predictable drug release characteristics.

碩士
國立臺灣科技大學
材料科學與工程系
102
Bioactive glass (BG) has attracted the attention of researchers for the last 50 years since it firstly reported at 1971 because of the bioactivity properties, and wide potential applications such as bone implants, tooth filling materials, and drug carriers. Bioactive glass forms hydroxyapatite (HA) layers on the surface of the BG that will generate strong chemical bond with tissue when it is implanted in a human body. To increase the HA formation, one of the popular approaches is to increase the surface area of BG by synthesize mesoporous bioactive glass (MBG). One of the applications of Mesoporous bioactive glasses are as bone implants that face a major problem with bacterial infections. The growth of bacteria in the bone implant that could lead to infection could be overcome by doped MBG by antibacterial agent such as silver (Ag). Sol-gel method is the most popular procedure to synthesize Ag-doped MBG; however, this method has some drawbacks of discontinuous processing, long processing time and unsuitable for mass production. To overcome these drawbacks, spray pyrolysis (SP) is an alternative procedure to synthesize Ag-doped MBG. In this study, Ag-doped MBG was successfully synthesized by using SP with tetraethyl orthosilicate, calcium nitrate tetrahydrate, triethyl phosphate, silver acetate and silver nitrate as the Ag-doped MBG precursors. The MBG particles will be characterized by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption isotherm for their crystallography structures, surface morphologies, and specific surface areas. Particles chemical element distributions were analyzed by using X-ray energy dispersive analysis and the dissolution profile of Ag-doped MBG is characterized using inductive coupled plasma for chemical analysis. The invitro bioactivity properties was analyzed by immersing the particles into simulated body fluid for certain hours and characterized by X-ray diffraction. Antibacterial property tests were conducted by using zone of inhibition method. Ag-doped MBG that with superior bioactivity and antibacterial properties were achieved by using the SP process, and silver distributions and particle formation mechanisms were also discussed.

碩士
國立臺灣海洋大學
生物科技研究所
101
In this study, the composite matrix containing mesoporous bioactive glass nanofiber and type I collagen were fabricated for bone graft materials. Type I collagen is a major constituent of bone tissue, and its amino sequence and quaternary structure can promote osteoblast attachment and differentiation. Mesoporous bioactive glass (MBG) possesses large pore volume and surface area and promotes bone regeneration process by release of calcium and phosphate ions. Hence, we firstly fabricated the mesoporous bioactive glass nanofibrous matrix (MBGNF) by sol-gel process and electrospinning technique. Subsequently, we fabricated the MBGNF-collagen composite with collagen fibrillar networks and large pores structure by gelation and freeze-drying process. Moreover, we investigated the physiochemical property, bioactivity and cellular response of osteoblasts on MBGNF-collagen composite. Finally, Bone regeneration in MBGNF-collagen composite was evaluated in vivo using a rat calvarial defect model.

碩士
國立臺灣海洋大學
生物科技研究所
99
In recent years, research in drug delivery systems (DDS) has received much attention owing to its drug delivery function and other features like surface modifications to act as controlled release systems. The surface of DDS can be modified by different functional groups to provide selectivity and specificity. We use mesoporous bioactive glass (MBG) as the carrier of drug delivery system, by combining the advantages of mesoporous materials and bioactive glasses, such as high surface area, adjustable pore size, fine surface chemical properties, biological stability, low toxicity and well biocompatibility, with functional group modified on the surface to achieve selective and specific ability of the materials and form a series of drug delivery systems. From current researches in cancer cells, we know there are much folic acid receptors over expressed in cancer cells from the body, so we can modified folic acid on the surface of the carrier and promote cell phagocytosis by the receptor-specific binding capacity to achieve the dual advantages of drug delivery and target treatment of cancer therapy. In this study, we use surface modification to graft folic acid on the surface of mesoporous bioactive glass, and marked with fluorescent molecules to observe the location of the material cultured with cells. Finally, we load anti-cancer drugs into the material and carry out drug release tests and in vitro cell toxicity tests to study the influences after folic acid modification, the effect of cancer cell targeting and controlled release ability.

碩士
國立臺灣科技大學
材料科學與工程系
107
With the development of science and technology and medical care, the average life expectancy of the world's population has prolonged, the problems faced by the aging population have gradually emerged. With age, the normal aging process will lead to the degradation of various physiological functions. According to statistics, the fall of the elderly is the second leading cause of accidental injuries. Fractures caused by falls or head trauma will increase the risk of infection and illness. According to reports, among the patients with diabetes in Taiwan, the elderly account for more than 40%, and the wound healing ability of diabetic patients is low. At this time, if the old man falls and fractures and wounds, and he has diabetes, it will be easy to be infected during surgery. It is an inflammatory reaction, but it is life-threatening. The resilience of the elderly is poor, and Mesoporous Bioactive glass (MBG) is biologically active and can carry drugs in its pores. When the drug-loaded MBG is placed in the human body, it will produce hydrogen and oxygen on the surface of the material. Hydroxyapatite (HA) can effectively help bone repair, and the loaded drug can reduce the chance of bacterial infection. It is a good biomedical and drug carrier material. In this study, spray pyrolysis (SP) and different concentrations of formic acid, acetic acid and lactic acid were added as pore-forming agents to prepare high specific surface area mesoporous bioactive glass. Increasing the specific surface area not only improved biological activity, but also increased drug load. the amount. The results of this study show that MBG with high specific surface area has high bioactivity and high drug release.

碩士
國立臺灣海洋大學
生命科學暨生物科技學系
103
Conversion and utilization of resources is a very economical concept of environmental protection and, while most people diatomaceous earth low value, can also be converted into high-value materials considered. In this study, the use of low-value diatomaceous earth to extract bio-silicon-silicon source, to prepare high value multifunctional bioactive glass in the holes, as a drug delivery system, to track the treatment of multi-functional applications. Because the holes in the bioactive glass has a high specific surface area, void volume and adjustable hole size, etc., and the material is easy on the surface modification of various functional groups, it can be connected to different receptors with drugs, making it easy to enter the target Tracking cells reach therapeutic effect. Therefore, this study takes advantage of mouse fibroblasts (L929 cell) and cervical cancer cell line (HeLa cell) for toxicity testing, and at the same time using conjugate fluorescence and confocal microscopy phagocytosis situation observed material and use with animal experiments tumors in nude mice injected subcutaneously into the material were observed with MRI development and IVIS fluorescent material position tracking material to explore whether this material has the effect of tracking treatment, and is able to inhibit tumor formation.

碩士
國立屏東科技大學
機械工程系所
97
Bioactive glasses have attracted much attention because of good biocompatibility and their wide usage as artificial biomaterials in bone repair and replacement. Bioactive glasses are widely used in many tissue engineering applications, such as in dental repairs and orthopedic fixation devices, as well as many others. Mesoporous bioactive glasses materials have received much interest because of their high specific surface area and pore volume, and exhibit better in vitro bone forming bioactivity compared to conventional bioactive glasses. In this study, mesoporous SiO2-CaO-P2O5 bioactive glass was prepared by sol-gel process and the synthesis was accomplished by using triblock copolymer and CTAB as the templates, tetraethyl orthosilicate, calcium nitrate tetrahydrate and triethyl phosphate as the inorganic precursors. The effects of Ca/P ratio of precursors and calcining temperatures on the structure of mesoporous SiO2-CaO-P2O5 bioactive glass were investigated by TGA, XRD, FTIR, SEM, TEM and BET analyses. Using triblock copolymer as the template, mesoporous SiO2-CaO-P2O5 bioactive glasses with the amorphous phase were obtained at 400~700°C for Ca/P ratio of 2:2, 3:2, 4:2 and 5:2. Using CTAB as the template and the samples calcined at 400~700°C were composed of amorphous phase for Ca/P ratio of 2:2, but apatite phase were formed as the calcining temperatures were 400~700°C for Ca/P ratio of 3:2, 4:2 and 5:2. The mesoporous SiO2-CaO-P2O5 bioactive glass is shown to have a large pore size of 400.29 Å for Ca/P ratio of 2:2 and using triblock copolymer as template after being calcined at 400℃. In addition, the mesoporous SiO2-CaO-P2O5 bioactive glass III also showed a high specific surface area of 706.16 m2/g at 600 ºC calcination for Ca/P ratio of 3:2 and using CTAB as template.

碩士
國立臺灣海洋大學
生物科技研究所
99
Research in intelligent drug delivery system is considerably interesting in biomedical fields. The system can be specifically stimulated to perform controlled drug release. In this study, mesoporous bioactive glass (MBG) act as an intelligent drug delivery carrier, modification of the pore outlets of the carrier with photo sensitive coumarin derivative may possess a gate-like block which can be stimulated by different wavelength of UV light to form open and close system. Exposure under UV light > 310 nm wavelength may form cyclobutane dimers through the coumarin derivative and trapping the guest molecules inside the pores. While irradiating the dimerized coumarin modified MBG with shorter wavelength UV light (~ 250 nm) will photo-cleavage the dimmers and regenerate coumarin monomer derivative, letting the guest molecules to release. In addition, doping rare earth element, europium, into the MBG structure allowed the MBG have the ability of photoluminescence, and its emission intensity will change with the cumulative released amount of the guest molecules in the carrier. Therefore, the extent of guest molecule release can be easily tracked and monitored by the change of luminescence. Herein, we use a model amino acid L-tryptophan as the guest molecule to test the modified MBG to present as an intelligent multi-controlled drug delivery system. Apart from the photoluminescent ability, lanthanides also have the characteristic of imitating calcium ion, which can replace some part of calcium ions in bone and activated the osteoblasts to promote bone formation and inhibit bone degradation and absorption. This calcium imitating capability makes lanthanide a potential treatment for bone diseases, and also makes the carrier a better intelligent drug delivery system for the application on bone repair treatments. The structural, morphological, textural and optical properties are well characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption/desorption, and photoluminescence spectra, respectively. The results reveal that the lanthanide doped MBG exhibits the typical ordered characteristics of mesostructure. The system demonstrates great potential in light-sensitive intelligent drug delivery systems and disease therapy fields.