Preparation Of Near Infrared Light Responsive PCL/MoS₂ Nanofiber Membrane And Study On Its Guidance Of Bone Regeneration

Objective:Bone defects can be repaired by nanofiber membranes and mild photothermal induction.Based on the osteoinductive,photothermal and mechanical properties of molybdenum disulfide（Mo S₂）,Mo S₂was mixed with polycaprolactone（PCL）and the nanofiber membranes PCL and PCL/Mo S₂with good biocompatibility,strong mechanical properties and near infrared light（NIR）response performance were constructed by electrospinning technology to guide bone regeneration.At the same time,we explored the osteoinductive properties of PCL/Mo S₂ nanofiber membranes in vivo and vitro under the NIR.Eeperimental method:using the method of Bovine Serum Albumin（BSA）assisted ultrasonic stripping to prepare Mo S₂nanosheets.Different concentration of Mo S₂ nanosheets and PCL were fully mixed,and PCL nanofiber membranes and PCL/Mo S₂nanofiber membranes were prepared by electrospinning technology.The morphological structure,chemical composition and mechanical properties of electrospun nanofiber membranes were characterized by scanning electron microscope（SEM）,Fourier transform infrared spectroscopy（FTIR）,X-ray diffraction and mechanical instruments,and the degradability of electrospun nanofiber membranes was explored.In addition,in order to study the photothermal performance of the PCL/Mo S₂ nanofiber membranes,we put the PCL/Mo S₂ nanofiber membranes under 808nm NIR for illumination,and recorded the temperature change over time.The SEM was used to observe the growth of bone marrow mesenchymal stem cells（BMSCs）on nanofiber membranes with different concentration.The CCK-8 was used to screen the concentration of the best biocompatibility from PCL nanofiber membranes,PCL/1%Mo S₂ nanofiber membranes and PCL/1.5%Mo S₂ nanofiber membranes.The cell viability and apoptosis of PCL and PCL/1%Mo S₂ nanofiber membranes under different light time were detected by CCK-8 and flow cytometry.The osteogenic effects of PCL and PCL/1%Mo S₂ nanofiber membranes under different light time were tested by q RT-PCR,ALP activity and Alizarin Red staining.The PCL and PCL/1%Mo S₂nanofiber membranes were implanted into the tibial defect of SD rats and exposed to NIR.The tibias were taken out after 4 or 8 weeks respectively,and the treatment effect was observed by micro CT,HE staining and immunohistochemistry.Experimental results:The SEM showed PCL and PCL/1%Mo S₂nanofiber membranes with smooth surface,uniform distribution,and large porosity.The results of FTIR and XRD showed that PCL and Mo S₂composite nanofiber membranes were successfully prepared.The results of mechanical tests,photothermal experiments and degradation experiments showed that the PCL/1%Mo S₂group had better mechanical properties and photothermal properties,and the PCL and PCL/1%Mo S₂nanofiber membranes were degradable.The results of SEM showed that the cells grew well on the nanofiber membranes,and the results of CCK-8 showed that the cell activity of PCL/1%Mo S₂ nanofiber membranes were the best.The results of CCK-8 and flow cytometry showed that PCL and PCL/1%Mo S₂ nanofiber membranes had better cell viability under different light time,especially PCL/1%Mo S₂-30s and PCL/1%Mo S₂-60s.The results of q RT-PCR,ALP activity and Alizarin Red staining showed that compared with PCL-0s,PCL-30s and PCL-60s,PCL/1%Mo S₂-0s,PCL/1%Mo S₂-30s and PCL/1%Mo S₂-60s had a good osteogenic effect in vitro,especially PCL/1%Mo S₂-60s.The PCL and PCL/1%Mo S₂ nanofiber membranes were implanted in the body and exposed to NIR.Temperature monitoring showed that the group of PCL/1%Mo S₂ rose to the target temperature.The general view of the sample,micro CT,HE staining and immunohistochemical results showed that PCL/1%Mo S₂+NIR group had the best bone repair effect.Experimental evidence:In this study,the PCL/Mo S₂composite nanofiber membranes were successfully prepared by electrospinning technology.The nanofiber membranes had good biocompatibility,mechanical properties and photothermal properties.The PCL/Mo S₂nanofiber membranes had no cytotoxicity under different light time,and had the ability to promote cell proliferation;at the same time,the nanofiber membranes had the ability to promote the osteogenic differentiation of BMSCs and promote bone defect repair in vivo.We successfully designed electrospinning nanofiber membranes with near-infrared light response performance and the nanofiber membranes can use photothermal performance to promote bone regeneration.