School of Materials Science and Engineering, Nanyang Technological University, Singapore.
J Biomater Sci Polym Ed. 2011;22(12):1651-67. doi: 10.1163/092050610X519471. Epub 2010 Aug 6.
α-Phase poly(vinylidene fluoride) (PVDF) has chains of zero dipole moments and is, therefore, nonpiezoelectric, while β-phase PVDF has the most significant piezoelectric properties among the polymorphs due to its polar chains. Although many reports describe PVDF as a suitable biomaterial due to its stability and biocompatibility, few considered the specific effects that the different polymorphs exert on cellular behaviour. We hypothesized that α- and β-phase PVDF will exert direct but different influences on cell attachment and metabolic activity. PVDF films were fabricated using N,N-dimethylformamide (DMF) and hexamethylphosphoramide (HMPA) by solvent casting. Samples were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy and X-ray diffraction. Films containing 83.5% α-phase PVDF (DMF-PVDFα) and 91.4% of β-phase PVDF (HMPA-PVDFβ within the crystalline regions were produced and used to evaluate in vitro attachment and metabolic activity of L929 cells. Cell metabolic activity on both PVDF conformations increased 3-fold over the 1-week culture period, with higher cell metabolic activity observed on DMF-PVDFα on day 5 of culture, compared to HMPA-PVDFβ. Cells grown on DMF-PVDFα were well-spread, flat and expressed spotted paxillin in focal adhesions that were mainly localized to perinuclear regions of the cells, while a high proportion of cells on HMPA-PVDFβ were bulging, round and expressed relatively fewer paxillin spots. Our results suggest that α-phase PVDF supports higher cell metabolic activity and better cell spreading compared to β-phase PVDF. Such variations can potentially be exploited for different biomedical applications.
α 相聚偏二氟乙烯（PVDF）的链段没有偶极矩，因此是非压电的，而β 相 PVDF 由于其极性链而具有所有多晶型物中最显著的压电性能。尽管许多报道将 PVDF 描述为一种稳定且具有生物相容性的合适生物材料，但很少有人考虑到不同多晶型物对细胞行为的具体影响。我们假设α相和β相 PVDF 将直接但以不同的方式影响细胞附着和代谢活性。使用 N,N-二甲基甲酰胺（DMF）和六甲基磷酰胺（HMPA）通过溶剂浇铸制备 PVDF 薄膜。通过差示扫描量热法、傅里叶变换红外光谱和 X 射线衍射对样品进行了表征。制备了含有 83.5%α相 PVDF（DMF-PVDFα）和 91.4%β相 PVDF（HMPA-PVDFβ）的结晶区的薄膜，并用于评估 L929 细胞的体外附着和代谢活性。在 1 周的培养期间，两种 PVDF 构象上的细胞代谢活性均增加了 3 倍，在培养的第 5 天，DMF-PVDFα上的细胞代谢活性更高，与 HMPA-PVDFβ相比。在 DMF-PVDFα上生长的细胞铺展良好，呈扁平状，在细胞的核周区域表达点状粘着斑蛋白，而在 HMPA-PVDFβ上生长的细胞中，有很大一部分细胞呈凸起状、圆形，并且表达相对较少的粘着斑蛋白斑点。我们的结果表明，与β相 PVDF 相比，α相 PVDF 支持更高的细胞代谢活性和更好的细胞铺展。这种变化可能会被用于不同的生物医学应用。
