Fabrication And Characterization Of PLA/HA-PDA Composite Nanofiber Scaffold

One of the major challenges in bone tissue engineering is to develop biomimetic scaffolds that are similar to the structures of natural bone.Electrospinning technique has been widely applied due to its advantages of easy making nanofiber structure similar to natural bone tissue and suitable for processing many kinds of composite.Polylactic acid(PLA)has a wide range of potential applications in the field of tissue engineering because of its excellent bioabsorbability,biodegradability and biocompatibility.However,PLA has some disadvantages for bone tissue engineering scaffolds,such as poor hydrophilicity and few cell recognition sites.It does mean that its integrated performance need to be further improved.In this paper,a new method of constructing functional tissue engineering scaffolds by using ultrasound-assisted technique is proposed and applied,which is designed to manufacture polymer scaffolds with high-performance that can mimic the nature bone tissues in both structure and function.The main contents include:(1)The poly(dopamine)(PDA)-hydroxyapatite(HA)(HA-PDA,HAp)composite nanoparticles with fine morphology and uniform dispersion were constructed by using ultrasound-assisted method.And then the PLA/HAp composite nanofiber scaffold was prepared by mixing the HAp nanoparticles with PLA by using electrospinning technique.The effects of HAp nanoparticles on the morphology,thermal properties,hydrophilicity and mechanical properties of PLA/HAp composite nanofiber membrane were studied.The results showed that the thermal properties,crystallization and mechanical properties of PLA/HAp composite nanofiber membrane were remarkably improved in compation with PLA nanofibers.(2)In order to further improve the biocompatibility and hydrophilicity of PLA/HAp composite nanofiber membrane,the surface of PLA/HAp composite nanofiber membrane was further modified by HAp composite nanoparticles viaultrasonic-assisted method.The HAp/PLA/HAp composite nanofiber membrane was prepared,which covered with HAp in the interior and the surface.The influence of HAp composite nanofiber on the morphology,thermal properties,hydrophilicityand mechanical properties on HAp/PLA/HAp composite nanofiber membrane were investigated.The results showed that the HAp/PLA/HAp composite nanofiber membrane not only maintains considerable mechanical properties,but also possess excellent hydrophilicity and water absorption due to the additional of HAp coating layer.The cell experiments results showed that HAp coating layer could effectively promote the growth and proliferation of mouse osteoblasts(MC3T3-E1)on the HAp/PLA/HAp composite nanofiber scaffold.(3)In order to overcome the disadvantage of the two-dimensional nanofiber scaffold prepared by traditional electrospinning,the three-dimensional PLA/HAp nanofiber structure was prepared by using liquid reservoir collection device instead of the traditional collection method.And then the three-dimensional 3D-HAp/PLA/HAp composite nanofiber scaffold was fabricated by using ultrasonic-assisted method.The influence of ultrasonic time and ultrasonic power on the mechanical properties,porosity and hydrophilicity were studied.the results showed that the mechanical properties,porosity and hydrophilicity of 3D-HAp/PLA/HAp porous composite nanofiber scaffold were remarkably improved in comparision with two-dimensional HAp/PLA/HAp nanofibers membrane.