Preparation Of Poly (Lactic Acid)/Nano-Calcium Phosphate Composite Fibers For Tissue Engineering Scaffolds

In this paper, electrospinning of PLA was studied systematically and the effective factors in the electrospinning were also demonstrated. The results indicated that when solvent is the mixture of DCM and DMF, a good solution system can be gained for electrospinning. DCM and DMF mixed with a volume ratio of 8:2 or 7:3 were all suitable solvent system. When the concentration of the PLA is fixed, the distance between spinneret and the receiver has an effect on diameter of the fibers. While the distance is less than 10cm, it is easy to form superfine fibers with the increasing of the voltage. Electrospinning for PLA can be carried out under the voltage between 9kV and 22kV. As the increasing of the voltage, the diameter of fibers decreased and electrospinning process became unsteady. The diameter of fibers was a key factor for the tensile properties of PLA electrospun fibers. With the increasing of concentration of PLA solution, the tensile strength of PLA fibers mats increased in the beginning and decreased gradually. The higher voltage in the electrospinning made the tensile strength of PLA fiber mats decreased. Tensile strength increased with the increasing of molecular weight of PLA.Based on the research of PLA, biomedical composite nanofibers were prepared with Nano-Calcium Phosphate (NCP) mixed into Poly lactic acid (PLA) by electrospinning and arranged oriented composite fibers were made by new electrospinning. A series of PLA solutions with weight concentration of 7% were produced and NCP with weight concentration 0, 1%, 3%, 5%, 7%, 9%, 11% and 13% were mixed into solutions and then electrospinning was carried out. The amount of NCP was the percentage of the weight of PLA. Transmission Electronic Microscope (TEM) indicated that NCP was mixed into PLA successfully. Scanning Electronic Microscope (SEM) showed that when the NCP concentration was less than 7%, the surface morphology of the fibers had no obvious changes. However, with increase of the NCP concentration, the electrospinning process became unsteady and the morphology of the fibers turned bad. As the NCP concentration had a deep increase, the morphology of the fibers became worse so that it was difficult to electro spin successfully. Tension tests indicated that NCP made a great effect on tensile strength of electrospun nanofibers. With the increase of NCP concentration, tensile strength increased ceaselessly and when the concentration exceeded 7% the strength decreased. The arranged oriented composite fibers were prepared by new electrospinning and characterized by SEM. The SEM images revealed that the fibers owed perfect orientation and their diameters were 2 or 3 times larger than those made by traditional electrospinning. When the NCP concentration was 0-7%, the electrospinning process was relatively steady. Nevertheless, when the NCP concentration increased to 9%-15%, the electrospinning became unsteady and fibers became discontinuous. It was very difficult to get fibers when the NCP concentration reached 15%.