Physical Properties And Biocompatibility Of3D Printed Bone Microparticle/Poly (Lactic-Co-Glycolic Acid) Scaffold

Objective: The objective is to study the physical properties and biocompatibility of rabbit allogeneic microparticle bone/PLGA composite absorbable scaffolds prepared by Fused Deposition Modeling(FDM)3D printing technology.Method: Microparticle bones with diameter ?30?m,prepared from cortical bones of New Zealand rabbit limbs,were fully mixed with poly(lactic-co-glycolic acid(PLGA)in a ratio of 1:5 to prepare a 3D printed wire with a diameter of 1.75 mm.Then a bone composite scaffold containing 20% rabbit allogeneic microparticle was printed by a FDM 3D printer.The appearance and internal structure of the scaffold were scanned by anScanning electron microscopy(SEM).The porosity,water contact angle and vickers hardness value,water absorption and in vitro degradation rate of the scaffold were measured.Rabbit adipose-derived mesenchymal stem cells(rADSCs)were isolated,cultured and identified for two passages,and the third passage rADSCs were cultured in scaffold-infiltrated medium of different concentration.CCK-8 toxicity test was used to detect scaffold cytotoxicity.Hemolysis test and acute toxicity test were used to evaluate scaffold biocompatibility.Results: Composite scaffold containing 20% rabbit allogeneic microparticle bone/PLGA printed by FDM 3D printing technology was successfully prepared.SEM showed:composite scaffold was porous,internal pore size was relatively uniform,pores were connected,inner layer was arranged in layers,internal bone powder structure was visible.The measured porosity was 60.86%±2.88%.The water absorption rate was 53.98%±2.04%.The water contact angle was 76.27±0.34 degree.The vickers hardness value is 27.84±0.47 HV.The composite scaffold was completely degraded within 11 weeks in vitro.The CCK-8 toxicity test showed that there was significant difference between the OD value of the each concentration of experimentalgroup and the OD value of the positive control group at each time point(p<0.05),and there was no significant difference compared with the negative control group(p>0.05).And the relative growth rate(RGR)of rADSCs was over 80%,indicating that the scaffold was at level 1 cytotoxicity,which was safe and qualified to use.The hemolysis rate was 3.8%,which met the hemolytic requirement(requiring hemolysis rate less than 5%)of biomedical materials.The hypersusceptibility test show that the material has no pyrogen.The acute toxicity test proved that the scaffold material was non-toxic and bio-compatible.Conclusion: The results show that the composite scaffold containing 20% rabbit allogeneic microparticle bone/PLGA scaffolds prepared by FDM 3D printing technology has preferable properties of porosity,hydrophilicity,high water absorption rate,strong degradability,mechanical character,and is non-toxic and bio-compatible.