3D Printing Of Borosilicate Bioglass Scaffold And Its Performance

As the living standards of people are improving than before,and the problem of aging of the social population is also increasing;therefore,the resulting osteoporosis disease,and the industry,transportation,sports,etc.caused accidental injuries are correspondingly,rising.People have increased and set higher requirements on the performance and demand of bone repair materials.Through combining biological materials,cells,and signaling factors,bone tissue engineering is a way to develop or replace traditional bone grafts to repair or even rebuild bone defects.The scaffolds are the most significantly decisive factor for tissue regeneration,as they can provide the necessary mechanical support and physical structure for the transplanted cells to facilitate transplanted cells' adhesion,growth,and scaffolds can maintain their physiological function on the material.3D printing,which is also known as rapid prototyping or additive manufacturing,is a technology that uses 3D data models to make physical objects,in which the main role of 3D printing technology is to construct scaffolds that provide templates which can be used for cell migration,adhesion,and eventual maturity.The main component of these scaffolds is biological glass,which is a kind of glass that can achieve specific biological or physiological functions.The scaffold made of biological glass is transplanted into the bone defect,and the surrounding bone tissue can be directly combined with it;therefore,scaffolds play the most important role of repairing the morphological structure and function.The borosilicate mentioned in the article is a new type of biological material,which can on one hand,promote bone repair by its conversion to hydroxyapatite,and on the other hand,promote bone repair through the activity of borate-induced bone regeneration.Based on the current situation,45S5 glass is mainly used in the current environment,and what can not be ignored is that the 45S5 biological glass block material prepared by the conventional high-temperature melting method is very brittle because of conventional high-temperature melting method,so it has been used in the form of flakes,fine powder,etc.Repair so far.Our laboratory has made some improvements using 58S(molar ratio:SiO2:CaO:P2O5=60:36:4)-B biological glass with better osteogenic differentiation ability,better mechanical properties,and biodegradability and the main research content is the following aspects:1.Adding B2O3 into silicate biological glass(58S glass)to prepare borosilicate glass for bone tissue engineering materials with different boron content(mass percentage 0,9.7,19.4,38.8,we call each of them as 58S-0B,58S-0.5B,58S-1B,58S-2B)They will be used for the preparation and performance research of the next biological glass scaffold.2.Using sodium alginate as a cross-linking agent,and using 3D printing extrusion deposition technology and sintering method to prepare 58S-OB,58S-1B,58S-1.5B,and 58S-2B scaffolds,the microstructure,mechanical properties,and in vitro biological properties of them(58S-0B,58S-1B,58S-1.5B and 58S-2B)scaffolds were also explored.Conclusions:? Micro-structure:The scanning surface electron microscope can be used to best see the mineralization phenomenon on the surface of the scaffolds after the degradation experiment.The mineralization phenomenon became increasingly obvious when the boron content increases? Mechanical properties:It can be summarized that the compression performance was becoming better as the boron content increases.?Biological activity:The rate of generation of hydroxyapatite in borosilicate glass is accelerated when the boron content increases.This tells that their biological activity is gradually increasing,and the corresponding degradation rate is also displaying a upward trend.? Cell compatibility:Glass has an inhibitory effect on the growth of osteoblasts if that glass has a high content of boron;however,the osteoblasts near the interface of the glass slide or on the surface of the glass slide still have a high survival rate in total,and it shows a relatively good growth morphology.3.Using sodium alginate as a cross-linking agent,and using 3D printing extrusion deposition technology to prepare the sintered 58S-1B(sintered at 600?,800?,1000? and 1200?)scaffold to get the four types of scaffolds we need.Their micro-structure,mechanical properties,and in vitro biological properties were separately studied.Conclusions:? Micro-structure:The scanning electron microscopy can better observe mineralization phenomenon on the surface of the scaffolds after the degradation experiment.The mineralization phenomenon becomes less obvious when the sintering temperature increases.?Mechanical performance:It can be concluded that the higher the sintering temperature,the better the compression performance based on compression performance tests.?Biological activity:The generation rate of hydroxyapatite of borosilicate glass decreases when the sintering temperature increases.This states that their biological activity gradually decreases,and its degradation rate also shows a downward trend on the same time.?Cell compatibility:Glass can inhibit the growth of osteoblasts when sintering temperature is getting higher;nevertheless,generally,osteoblasts near the interface of the glass slide or on the surface of the glass slide still have a high survival rate and a relatively good growth morphology.Based on the reasoning above,the 58S-B scaffolds produced by 3D printed in this research have good mechanical properties(excluding ones sintering under 600?),and can promote the proliferation of rMSCs in vitro,through distinctly controlling the difference in boron content in the scaffolds and the sintering temperature.We can match the growth time of new bone of patients via adjusting the degradation time that we need.Therefore,these scaffolds are potential bone defect repair materials have incredibly important application prospects in bone tissue engineering.