ABSTRACT
BACKGROUND: Preliminary studies have found that poly(lactic-co-glycolic acid) (PLGA) can improve the compressive strength and degradability of calcium phosphate cement. OBJECTIVE: To prepare a self-setting calcium phosphate cement which has better mechanical properties, biocompatibility and degradability on the basis of the previous findings. METHODS: Beta-tricalcium phosphate (β-TCP), pure calcium phosphate cement (CPC) and PLGA powder were mixed at different mixing ratios for preparation of PLGA/β-TCP/CPC. Setting time, compressive strength, elastic modulus and degradation properties of the composite bone cement were evaluated to screen the optimal level of β-TCP. MC3T3-E1 cells were cultured in CPC extract (control), PLGA/β-TCP/CPC extract (experimental), α-MEM containing 10% fetal bovine serum and 1% penicillin-streptomycin double antibody (negative control), and 6.4% phenol liquid (positive control). MTT method was used to detect cell proliferation at 1, 3, 5 days after culture, and lactate dehydrogenase activity in culture media was detected at 1 and 3 days after culture. MC3T3-E1 cells were seeded on the surface of PLGA/β-TCP/CPC and pure CPC respectively, and were then observed by scanning electron microscopy after 3 days. RESULTS AND CONCLUSION: Initial setting time and final setting time among of the composite bone cement were increased with the increasing of β-TCP content, but had no significant difference from those of the CPC (P ＞ 0.05). The compressive strength and elastic modulus of the composite bone cement were higher than those of the CPC, and moreover, the composite bone cement with 20% β-TCP exhibited the highest compressive strength and higher elastic modulus as compared with the other groups. Therefore, PLGA/20% β-TCP/CPC was selected in the cell test. Moreover, the degradation properties of the composite bone cement were also better than those of the CPC. (3) With the growth of culture time, cell absorbance value and lactate dehydrogenase activity were gradually increased in the experimental group, and no difference existed between the experimental group and the negative control group. The cells in the experimental group also grew well. (4) MC3T3-E1 cells grew well and fully extended on the surface of PLGA/β-TCP/CPC, and cell pseudopodia on the material surface were tightly adhered to the material. To conclude, PLGA/20% β-TCP/CPC has better compressive strength, elastic modulus, degradation properties and cytocompatibility relative to the CPC, and moreover, the composite bone cement has no obvious cytotoxicity.