Preparation, Characterization And In Vitro Analysis Of A Kind Of Fictional Nano-scaffolds For Bone Tissue Engineering

BackgroundTraumatic osteomyelitis and bone defect are two kinds of disease hard to cure in nowadays clinical orthopedics. The osteomyelitis especially the chronic ones are quite troublesome during the treatments because of deep lesion, high recurrence and many other reasons. While the large area of bone defect cause of trauma is also hard to remedy for lacking of applicable bone alternates and high infection risk. The developing of nano-materials strongly impels the career of treating traumatic large area bone defect and osteomyelitis. This research began with a wholly and extensionally analyzing of the research progress in the treatment of bone defect or osteomyelitis with drug-carried nano-hydroxyapatite composite. It including the designing and preparing of drug-carried nano composites and the way of making infected bone defect animal models. We more summarizing the generally steps, examine criterions and result evaluations. We hope to offer some theoretic supports and experimental references to our later study. Although many researchers made artifical bone with nano-materials and add drugs into them by various ways for the purpose of controlling infection and repairing the bone defection simultaneously, these research are still in the laboratory phase, lacking the criterions of making relative animal models and need to be improved in the way of drug slow-releasing and nano-scaffold producing. In a word, the drug-carried nano-alternate bone as a newly emerging replacement materials have splendid effects in the treatments of traumatic large area bone defect and osteomyelitis and will have a brilliant future.ObjectiveConsidering the demands of lasting antibacterial property and histocompatibility of artifical bone in clinic. We combined chitosan which encapsulating etimicin with nano-hydroxyapatite to prepare a fictional drug-carried bone scaffold in order to offer assistances for treating bone defect or osteomylitis in clinic.MehtodsDrug-carried chitosan nanoparticles prepared by ionotropic gelation combined with nano-hydroxyapatite freeze-dry to prepare the porous scaffold. The characterization of scaffold was experimented by scanning electron microscope, X-ray diffraction and total porosity mensuration. Bacterial and drug releasing experiments to measure its antibacterial and slow-release property. We introduced bone mesenchymal stem cells to detect the histocompatibility and inductivity of etimicin-carried sasffold.ResultsDrug-carried chitosan nanoparticles were prepared by measure of ionotropic gelation. We discussed the relationships between concentrations of chitosan or tripolyphosphate and yield or quality of nanoparticles. Etimicin is a kind of partial synthesis aminoglycosides which has advantages of highly antibacterial property and water solubility which make it easy to be encapsulated. Nano-hydroxyapatite as a raw material could provide high histocompatibility and adsorbable property. The discussion of hydroxyapatite addition and scaffold’s drying way made the drug-carried bone scaffold possess superior physico-chemical property as far as possible Freeze-dried porous scaffold has a globular and coliformed microstructure, proper pore distribution(total porosity70.68%) after scaned by electron microscope. It has a typical waveform of hydroxyapatite under X-ray diffraction, no waveform was appeared in chitosan granules. With choosing staphylococcus aureus as the experimental bacteria, blank bone scaffold and pure chitosan as comparison, we studying lasting antibacterial property of drug-carried bone scaffold. As a result, it maintained a inhibition zone for more than7days. The fictional drug-carried bone scaffold released above the bacteriostasis concentration after one week and the accumulative amount within the safety scale The fictional scaffold also has a satisfactory drug-carried and encapsulating ratio.The human bone mesenchymal stem cells were cultivated in situ. Cells bespreaded the bottom after9days’passage. The multiclone stem cells’bodies were long and narrow which was similar to fibroblasts. Cells were gathered in a swirl form. The scaffold was co-cultured with bone mesenchymal stem cells. Tropism growth and firm adhesion signified the excellent histocompatibility and non-cytotoxic of the scaffold, Osteogenesis differentiation and quantities of calcium nodules among stem cells were displayed after7days’co-culture. The alizarin red staining showed significant deviation in the number of calcium nodules between experimental group and control group which also certified the scaffold can lead mesenchymal stem cells to osteogenic differentiation.ConclusionThe etimicin-encapsuled chitosan/hydroxyapatite nano-scaffolds has similar microstructure and components of bone tissue, superior slow-release, antibacterial properties and satisfactory histocompatibility make it a brilliant artifical bone substitution.