Preparation And Properties Of Nano Lithium Magnesium Silicate-Chitosan-Sodium Alginate Composite Scaffold Materials

Objective:Since the beginning of the 21 st century,tissue engineering has become a major frontier subject in the field of life science.Bone tissue engineering,which is a member of tissue engineering has become a research hotspot in bone defect reconstruction.Bone tissue engineering includes three major elements: seed cells,growth factors and scaffold materials.Among them,the scaffold material plays an important role and has increasingly become a key link restricting the development of bone tissue engineering.In the current research,natural high-density materials,synthetic materials with better biocompatibility,biodegradability and mechanical stability have been widely used in the research of tissue engineering scaffold materials.However,a single type of material is usually difficult to meet the many requirements of ideal bone tissue engineering scaffold materials in terms of mechanical,physical,chemical and biological properties.Therefore,the selection and preparation of scaffold materials become the current research hotspot of bone tissue engineering.In this study,the three materials of nano lithium magnesium silicate(nLMS),chitosan(CS)and sodium alginate(SA)were used for compounding,and a new type of composite scaffold material was prepare.Then,characterized the materials,and analyzed its microscopic morphology and pore structure.In terms of physical and chemical properties,the materials were tested for water absorption swelling rate,porosity,and in vitro degradability.By co-cultured with L929 cells in vitro,the biocompatibility of the materials was evaluated.Finally,the effect of nano-lithium magnesium silicate(nLMS)content on the physical,chemical and biological properties of the composites were discussed.Methods:Prepared 0%,1%,2%,3%,and 4% lithium magnesium silicate hydrogelsrespectively and then mixed with 6% chitosan and 4% sodium alginate.The solution-gel method was used to prepare nano lithium lithium silicate(nLMS)-chitosan(CS)-Sodium alginate(SA)composite material and porous composite scaffold materials were obtained by vacuum lyophilized.The Fourier Infrared Spectroscopy(FT-IR),Scanning Electron Microscope(SEM)and Asphalt Pycnometer were used to detect the micro-morphology,structure,pore size,and porosity of the material.The hydrophilicity and degradability of the material were evaluated by water absorption swelling and in vitro weight loss test.The extractions of the scaffolds were co-cultured with mouse fibroblasts(L929)in vitro for 48 h,and the cytotoxicity of the materials were evaluated by CCK-8 method.Results:1.The prepared nano-lithium magnesium silicate(nLMS)-chitosan(CS)-sodium alginate(SA)composite scaffold materials had basically the same visual appearance,and all were in the form of white columns,with a loose and porous three-dimensional structure and ultra-low density.Under the scanning electron microscope,it could be seen that the longitudinal section of the material was lamellar,and the loose internal pores of the structure were highly connected.2.FTIR results showed that each component material had been successfully introduced into the composite scaffold,and the materials were connected by electrostatic force or hydrogen bonding without chemical reaction.3.The water absorption swelling experiment showed that the materials of each group had good hydrophilicity.The addition of LMS made the swelling rate and porosity of the scaffold material decrease at beginning and then increase.Among them,the swelling rate of the scaffold material in the 3% group was the lowest,The porosity of the 2% and 3% groups were low,and the difference between the groups was statistically significant(P<0.05).The Results of weight loss rate experiment after immersing the scaffold materials in phosphate buffer solution for 7 weeks,the degradation time of the experimental groups were longer than that of the blank group,among them,the 3%group degraded most slowly.4.The cytotoxicity experiment results indicated that the cytotoxicity of the material extraction of the experimental group was level 0,which indicated that the former had bettert biocompatibility compared with level 1 of the blank group.Conclusions:1.Nano lithium magnesium silicate-chitosan-sodium alginate(nLMS-CS-SA)composite scaffold material was successfully synthesized by solution-gel method and freeze-drying technology,which had good plasticity,loose and porous three-dimensional network structure.2.Compared with the blank CS-SA scaffold material,the composite scaffolds with nLMS had lower porosity,and had more advantages in hydrophilic swelling,stability,the degradation time in vitro was extended and with good cell compatibility.All of above indicated the novel composite scaffold materials prepared using of inorganic material nano lithium magnesium silicate,sodium alginate and chitosan exhibited more excellent performance than simple chitosan-sodium alginate scaffold,and it was expected to be further studied in the field of tissue engineering application.