1,721,217 research outputs found
Biomedical, therapeutic and clinical applications of bioactive glasses
Full text linkBiomedical, Therapeutic and Clinical Applications of Bioactive Glasses is an essential guide to bioactive glasses, offering an overview of all aspects of the development and utilization of this cutting-edge material. The book covers vital issues, including mesoporosity, encapsulation technologies, scaffold formation and coatings for a number of applications, including drug delivery, encapsulation, scaffolds and coatings. Readers will gain a strong understanding and practical knowledge of the therapeutic aspects of bioceramics, with a focus on glasses from a clinical point-of- view. Researchers, students and scientists involved in bioceramics, bone tissue engineering, regeneration and biomedical engineering will find this to be a comprehensive resource
Bioceramics: Status in Tissue Engineering and Regenerative Medicine
No full textTissue engineering and regenerative medicine seek biomaterials with potent regenerative potential in vivo. The bioceramics superfamily represents versatile inorganic materials with exceptional compatibility with living cells and tissues. They can be classified into three distinctive groups including almost bioinert (e.g., alumina and zirconia), bioactive (bioactive glasses (BGs)), and bioresorbable (e.g., calcium phosphates (CaPs)) ceramics. Regarding their physicochemical and mechanical properties, bioceramics have been traditionally used for orthopedic and dental applications; however, they are now being utilized for soft tissue healing and cancer theranostics due to their tunable chemical composition and characteristics. From a biological perspective, bioceramics exhibit great opportunities for tissue repair and regeneration thanks to their capability of improving cell growth and proliferation, inducing neovascularization, and rendering antibacterial activity. Different formulations of bioceramics with diverse shapes (fine powder, particles, pastes, blocks, etc.) and sizes (micro/ nanoparticles) are now available on the market and used in the clinic. Moreover, bioceramics are routinely mixed into natural and synthetic biopolymers to extend their applications in tissue engineering and regenerative medicine approaches. Current research is now focusing on the fabrication of personalized bioceramic-based scaffolds using three-dimensional (3D) printing technology in order to support large-volume defect tissue regeneration. It is predicted that more commercialized products of bioceramics will be available for managing both hard and soft tissue injuries in the near future, either in bare or in combination with other biomaterials
Quantifying the adhesion of silicate glass-ceramic coatings onto alumina for biomedical applications
Full text linkDeposition of bioactive glass or ceramic coatings on the outer surface of joint prostheses is a valuable strategy to improve the osteointegration of implants and is typically produced using biocompatible but non-bioactive materials. Quantifying the coating–implant adhesion in terms of bonding strength and toughness is still a challenge to biomaterials scientists. In this work, wollastonite (CaSiO3)-containing glass–ceramic coatings were manufactured on alumina tiles by sinter-crystallization of SiO2–CaO–Na2O–Al2O3 glass powder, and it was observed that the bonding strength decreased from 34 to 10 MPa as the coating thickness increased from 50 to 300 µm. From the viewpoint of bonding strength, the coatings with thickness below 250 µm were considered suitable for biomedical applications according to current international standards. A mechanical model based on quantized fracture mechanics allowed estimating the fracture toughness of the coating on the basis of the experimental data from tensile tests. The critical strain energy release rate was also found to decrease from 1.86 to 0.10 J/m2 with the increase of coating thickness, which therefore plays a key role in determining the mechanical properties of the materials
Copper-doped ordered mesoporous bioactive glass: A promising multifunctional platform for bone tissue engineering
Full text linkThe design and development of biomaterials with multifunctional properties is highly attractive in the context of bone tissue engineering due to the potential of providing multiple therapies and, thus, better treatment of diseases. In order to tackle this challenge, copper-doped silicate mesoporous bioactive glasses (MBGs) were synthesized via a sol-gel route coupled with an evaporation-induced self-assembly process by using a non-ionic block co-polymer as a structure directing agent. The structure and textural properties of calcined materials were investigated by X-ray powder diffraction, scanning-transmission electron microscopy and nitrogen adsorption-desorption measurements. In vitro bioactivity was assessed by immersion tests in simulated body fluid (SBF). Preliminary antibacterial tests using Staphylococcus aureus were also carried out. Copper-doped glasses revealed an ordered arrangement of mesopores (diameter around 5 nm) and exhibited apatite-forming ability in SBF along with promising antibacterial properties. These results suggest the potential suitability of copper-doped MBG powder for use as a multifunctional biomaterial to promote bone regeneration (bioactivity) and prevent/combat microbial infection at the implantation site, thereby promoting tissue healing
3D printing of hierarchical scaffolds based on mesoporous bioactive glasses (MBGs)-fundamentals and applications
Full text linkThe advent of mesoporous bioactive glasses (MBGs) in applied bio-sciences led to the birth of a new class of nanostructured materials combining triple functionality, that is, bone-bonding capability, drug delivery and therapeutic ion release. However, the development of hierarchical three-dimensional (3D) scaffolds based on MBGs may be difficult due to some inherent drawbacks of MBGs (e.g., high brittleness) and technological challenges related to their fabrication in a multiscale porous form. For example, MBG-based scaffolds produced by conventional porogen-assisted methods exhibit a very low mechanical strength, making them unsuitable for clinical applications. The application of additive manufacturing techniques significantly improved the processing of these materials, making it easier preserving the textural and functional properties of MBGs and allowing stronger scaffolds to be produced. This review provides an overview of the major aspects relevant to 3D printing of MBGs, including technological issues and potential applications of final products in medicine
Modelling the elastic mechanical properties of bioactive glass-derived scaffolds
Full text linkPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson's ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson's ratio is well fitted by a linear equation
Bioactive Glasses and Glass-Ceramics
No full textThe application of some special glass compositions to make implantable biomaterials has revolutionized the medical field and introduced the concept of “surface-active” or “bioactive” materials, which have the ability to elicit a specific biological response at the interface with the surrounding tissue. This property typically results in the formation of a tight bond between glass implant and living tissue and promotes the processes of tissue healing. Therefore, it is easy to understand how much such materials are appealing for biomedical purposes and why they have been so intensively investigated in the last decades. Controlled crystallization allows modulating the durability, bioactivity and mechanical properties of the glass-ceramics derived from the parent glasses. Furthermore, the easiness of doping glass compositions with specific therapeutic elements has recently led to the development of a range of melt-derived or sol-gel glasses that exhibit highly-attractive properties related to discouraging bacterial adhesion, sprouting angiogenesis (i.e. the ability to increase the formation of new blood vessels) and treating cancer
On the Biocompatibility of Bioactive Glasses (BGs)
No full textBioactive glasses (BGs) form a versatile class of biocompatible materials that can be utilized for various therapeutic strategies, including bone tissue engineering, soft tissue healing, and cancer therapy. Commonly, BGs are classified into three distinct categories, namely silicate, phosphate, and borate glasses. Several commercial BG-based products are now available on the market, and new generations with unique therapeutic features are also expected to introduce them in the near future. Due to their clinical significance, the biological behaviors of BGs have been one of the most interesting topics in tissue engineering and regenerative medicine. Although BGs are generally recognized as biocompatible materials in medicine, any new composition and formulation should be carefully tested through a series of standard in vitro and in vivo tests provided by international agencies (e.g., Food and Drug Administration (FDA)) and regulatory bodies (e.g., the International Organization for Standardization (ISO)). As a rule of thumb, the release of ionic dissolution products from BGs into the surrounding biological environment is regarded as the main parameter that modulates cellular and molecular phenomena. This process is even more crucial when specific elements (strontium, copper, etc.) are added to the basic composition of BGs to improve their physico-chemical properties, mechanical strength, and biological performance. Moreover, it is now well-established that some physical (e.g., the topography) aspects of BGs can directly affect their compatibility with the living systems (cells and tissues). Therefore, a multifaceted design and testing approach should be applied while synthesizing BGs in the laboratory, and the collaboration of materials and chemical engineers with biologists and medical experts can be really helpful for producing optimized formulations
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