Preparation And Properties Of A Novel 3D-printed PLGA/COLI Porous Composite Scaffold

Background:Tissue engineering is a new direction for cartilage defect repair,and scaffold material,as one of three elements of tissue engineering,plays an important role in the construction of tissue engineering cartilage.Poly lactic-glycolic acid(PLGA),a synthetic polymer material,is characterized by good mechanical properties,high plasticity,high porosity,and controlled degradation,but poor hydrophilicity and weakly acid degradation products,Type-I collagen(COLI),a natural macromolecule material,is characterized by excellent biocompatibility and hydrophilicity,but poor mechanical properties,rapid degradation.Low-temperature deposition manufacturing(LDM),a typical 3D prototyping technology,has unique advantage of preserving the structure of natural materials due to the ultra-low temperature manufacturing platform and the combination of phase separation.It is a e green manufacturing technology.Purpose:PLGA and COLI were homogenously mixed,making up for weaknesses,expending advantages.The purpose of this study is to fabricate a novel PLGA/COLI porous composite scaffold and explore its properties.Methods:1.PLGA and PLGA/COLI composite scaffolds were prepared by LDM and the scaffolds'morphological structure,pore size,porosity,hydrophilicity,mechanics and composition were examined.2.The rabbit bone marrow mesenchymal stem cells were isolated,cultured and passaged,and then were co-cultured with the scaffolds.Cell counting kit-8(CCK-8)assay was used to detect cell proliferation on the scaffolds.Live-death cell staining and scanning electron microscope was used to detect adhesion,distribution,and morphology of the cells on the scaffolds.3.We compared the in vitro degradation of PLGA and PLGA/COLI scaffolds.Themorphology,volume,quality and degradation solution's PH changes were investigated.This study provides a theoretical basis for the further in vivo application of the composite scaffold.Results:The PLGA and PLGA/COLI scaffolds prepared by LDM have good three-dimensional porous structure.The macro-pore size and micro-pore size were round and interconnected.The composite scaffold had larger micro-pores,higher porosity and better hydrophilicity.FTIR examination confirmed that the composite scaffold consisted of PLGA and COLI.The mechanical properties of the composite scaffolds were decreased,but closer to human natural cartilage.The result of CCK-8 assay illuminated that the cell showed better proliferationon the composite scaffold.Scanning electron microscope and Live-death cell staining showed that the cell adhere,distribution and morphology were better on the composite scaffold.Degradation experiment results revealdthat the weight loss of the composite scaffold was faster,but the volume loss is slower.The degradation solution's PH of the composite scaffold was lower than that of PLGA scaffold before 16~thh week,and reversed after that.Conclusion:The structure of the 3D-printedPLGA/COLI scaffold is excellent,and it showed better physical,chemical properties and biocompatibility.Although PLGA/COLI scaffoldshowed fast degradation behaviors,it maintained a good three-dimensional structure within 8 weeks.COLI may help to buffer the acidity of PLGA degradation products.PLGA/COLI scaffold may be one of the ideal scaffolds for cartilage tissue engineering.