2022, Vol. 26 ›› Issue (28): 4446-4451

Electroactive membrane promotes bone formation in rats in vivo

He Yiheng, Cheng Mingwei, Zhu Peijun, Xu Yan, Chen Jiahao, Lai Chunhua, Xu Shulan   

Abstract: BACKGROUND: The previous research of our group found that polarized poly(vinylidenefluoride-trifluoroethylene) has the effect on regulating the proliferation and differentiation of osteoblasts in vitro, but the role of polarized poly(vinylidenefluoride-trifluoroethylene) membrane in promoting bone defect healing in vivo is not clear.
OBJECTIVE: To establish a rat model of critical bone defect in mandible and evaluate the effect of polarized poly(vinylidenefluoride-trifluoroethylene) in promoting the healing of bone defect in vivo.
METHODS: The poly(vinylidenefluoride-trifluoroethylene) membrane was prepared by flow-casting method, and after corona polarization treatment, it obtained good and stable piezoelectric properties. The physicochemical properties, electrical properties and biocompatibility of the membrane before and after polarization were characterized. Critical full-thickness bone defects with a diameter of 4 mm were prepared in eighteen Wistar rats with bilateral mandibular angles. Rats were randomly divided into three groups (n=6). Polarized poly(vinylidenefluoride-trifluoroethylene) membrane was implanted in the experimental group, and unpolarized poly(vinylidenefluoride-trifluoroethylene) membrane was implanted in the control group. The blank control group was not treated. At 4 and 8 weeks, Micro-CT scanning was used to analyze the amount of bone formation in each group, and tissue staining was used to observe the bone formation in each group. The experimental protocol was approved by the Animal Experiment Ethics Committee of Southern Medical University (approval No. 00225515).
RESULTS AND CONCLUSION: (1) The surface morphology, water contact angle, elastic modulus and maximum tensile strength of poly(vinylidenefluoride-trifluoroethylene) membrane after polarization had no obvious changes. The electrical constant was -10 pc/N, and the surface potential was -83 mV. (2) The results of cell proliferation-toxicity assay showed that the polarized poly(vinylidenefluoride-trifluoroethylene) membrane promoted the proliferation of bone marrow mesenchymal stem cells, but did not produce toxic reaction to the cells. (3) At 4 and 8 weeks postoperatively, the results of Micro-CT showed that the amount of bone formation in the bone defect area of the experimental group was significantly higher than that of the control group and the blank control group (P < 0.05). (4) At 4 and 8 weeks after operation, hematoxylin-eosin staining showed that the healing speed and quality of bone tissue in the experimental group were significantly better than those in the control group and the blank control group. (5) Immunohistochemical staining at 4 and 8 weeks postoperatively showed that expression of Runx2 in the bone defect area of the experimental group was higher than that of the control group and the blank control group (P < 0.05). (6) The results showed that the polarization poly(vinylidenefluoride-trifluoroethylene) membrane had good physical and chemical properties, biocompatibility and osteogenic properties in vivo.
Key words: bionic electroactivity, piezoelectric polymer, electroactive materials, guide bone regeneration, guide bone regeneration membrane, bone tissue engineering, bone replacement material, critical bone defect