ABSTRACT
BACKGROUND: To retain more biological activity of organic matter and materials, it is necessary to grind and refine the pearl powder by physical method. The ball grinding method can retain the organic matter in the pearl powder and its activity to the greatest extent. The nanomaterials prepared by ball milling in different dispersion media exhibit different effects. OBJECTIVE: To compare nano-pearl powder milled with distilled water and anhydrous ethanol. METHODS: Nano-pearl powder was prepared by grinding with anhydrous ethanol and water as dispersion medium respectively. The prepared nano-pearl powder was compared by scanning electron microscope, transmission electron microscope, X-ray diffraction, Kjeldahl method and by determining amino acid content in foods. RESULTS AND CONCLUSION: (1) The nano-pearl powder prepared with anhydrous ethanol as dispersion medium was mainly round particles of different sizes (range, 30-50 nm), with the average grain size of 20 nm. The relative percentage of calcite calcium carbonate increased to 7%. The contents of protein and amino acid did not change obviously. (2) The nano-pearl powder prepared with distilled water as dispersion medium was mainly round particles of different sizes with the average grain size of 30 nm. There were irregular grain-like or block-like particles. The relative percentage of calcite calcium carbonate increased to 10%. The contents of protein and amino acid decreased. (3) These results showed that there was a significant difference in the particle size of the pearl powder ground with distilled water and anhydrous ethanol. The pearl powder prepared with anhydrous ethanol as the dispersion medium had a finer more uniform particle size.
ABSTRACT
OBJECTIVES@#To evaluate the repairing ability of nano-pearl powder bone substitute in rabbit with defect of distal femur bone.@*METHODS@#Thirty-two New Zealand rabbits were randomly divided into four groups: a nano-pearl powder/recombinant human bone morphogenetic protein 2 (rhBMP-2)/hyaluronic acid group, a nano-pearl powder/hyaluronic acid group, a nano-pearl powder group and a blank control group (=8 in each group). A defect with the diameter of 7 mm and height of 10 mm was prepared at the distal femoral metaphysis line of the rabbit.Different bone substitutes were planted, and the effect of repair was evaluated by macroscopic observation, imaging examination, and histopathological examination.@*RESULTS@#The results of imageology showed that: the bone repairing effect in the nano-pearl powder/rhBMP-2/hyaluronic acid group was better than that in the pure pearl powder group and the nano-pearl powder/hyaluronic acid group, and which in the 3 experimental groups was better than that in the blank control group; The results of histology showed that: at the 4th, 8th and 12th weeks after the modeling operation, the speed of bone repair in the nano-pearl powder/rhBMP-2/hyaluronic acid group was faster than that in the pure pearl powder group and the nano-pearl powder/hyaluronic acid group, and which in the blank control group was far slower than that in the 3 experimental groups. The results of immunohistochemistry staining for osteocalcin antibody showed that: the osteogenic effect in the nano-pearl powder/rhBMP-2/hyaluronic acid group was better than that in the pure pearl powder group and the nano-pearl powder/hyaluronic acid group (both 0.05); however, there was significant difference between the pure pearl powder group and the blank control group (0.05), but the osteogenic effect in the nano-pearl powder/hyaluronic acid group was better than that in the pure pearl powder group and the blank control group (both <0.05).@*CONCLUSIONS@#Nano-pearl powder and its bone substitute can promote the repair of bone defect, and the nano-pearl powder which contains rhBMP-2 has better osteogenic and repairing effect on defect.