Chung Tze-Wen, Wang Yen-Zen, Huang Yi-You, Pan Chin-I, Wang Shoei-Shen
Department of Chemical Engineering, National Yunlin University of Science and Technology, Douliou, Yun-Lin, Taiwan.
Artif Organs. 2006 Jan;30(1):35-41. doi: 10.1111/j.1525-1594.2006.00178.x.
Polyester films are modified with their bioactivity for tissue engineering by grafting a nano-structured bioactive material, nano-structured chitosan (nano-CS), on a model polymer, poly (epsilon-caprolactone) (PCL). The nano-CS was duplicated using a solvent-etched PCL mold and then grafted onto PCL using a selected solvent. The structure of the nano-CS/PCL surface was characterized using an atomic force microscope to observe the topography and determine the roughness. The centerline average roughness, Ra, of the surface of the nano-CS/PCL film is 106.0+/-4.0 nm whereas that of the surface of the CS-grafted PCL film (CS/PCL) is 3.6+/-0.4 nm. The latter is therefore very smooth. CS is known to swell following hydration, so the Ra values were determined again after immersion for 12 h in phosphate buffered saline. Although the centerline average roughness of the nano-CS/PCL was lower, it still markedly exceeded that of the CS/PCL film. Cells grown on nano-CS/PCL, CS/PCL, nano-structured PCL (nano-PCL), and PCL films were observed by fluorescent staining and analyzed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) viability assay following 3 and 7 days of culture, to evaluate the effects of the design on the growth of fibroblasts. The viability assay of the cells reveals that the growth rate of cells on both CS/PCL and nano-CS/PCL films significantly exceeds (P<0.001) those of PCL and nano-PCL films on both cultural days. Additionally, the growth rate and proliferation of fibroblasts on nano-CS/PCL films significantly exceed (P<0.001) those on CS/PCL films after both periods of culturing, suggesting that the bioactive surface following a nano-structured treatment promotes the growth rate of cells. However, nano-PCL films do not have the same effects as nano-CS/PCL films do. In conclusion, a novel biomaterial, nano-CS/PCL, is developed by grafting a nano-structured bioactive surface, CS, onto the PCL surface to promote the the growth rate of fibroblasts. This work elucidates a new concept for designing films or scaffolds for tissue engineering-the grafting of nano-structured bioactive biomaterials to the films or scaffolds to promote the growth of cells.
通过将纳米结构的生物活性材料——纳米结构壳聚糖（nano-CS）接枝到模型聚合物聚（ε-己内酯）（PCL）上，对聚酯薄膜进行生物活性改性，用于组织工程。使用溶剂蚀刻的PCL模具复制纳米CS，然后使用选定的溶剂将其接枝到PCL上。使用原子力显微镜对纳米CS/PCL表面的结构进行表征，以观察表面形貌并确定粗糙度。纳米CS/PCL薄膜表面的中心线平均粗糙度Ra为106.0±4.0nm，而接枝壳聚糖的PCL薄膜（CS/PCL）表面的Ra为3.6±0.4nm。因此，后者非常光滑。已知壳聚糖在水合后会膨胀，因此在磷酸盐缓冲盐水中浸泡12小时后再次测定Ra值。尽管纳米CS/PCL的中心线平均粗糙度较低，但仍明显超过CS/PCL薄膜的粗糙度。通过荧光染色观察在纳米CS/PCL、CS/PCL、纳米结构PCL（nano-PCL）和PCL薄膜上生长的细胞，并在培养3天和7天后通过MTT（3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐）活力测定进行分析，以评估该设计对成纤维细胞生长的影响。细胞活力测定表明，在两个培养日，CS/PCL和纳米CS/PCL薄膜上细胞的生长速率均显著超过（P<0.001）PCL和纳米PCL薄膜上细胞的生长速率。此外，在两个培养期后，纳米CS/PCL薄膜上成纤维细胞的生长速率和增殖均显著超过（P<0.001）CS/PCL薄膜上的，这表明纳米结构处理后的生物活性表面促进了细胞的生长速率。然而，纳米PCL薄膜没有与纳米CS/PCL薄膜相同的效果。总之，通过将纳米结构的生物活性表面壳聚糖接枝到PCL表面，开发了一种新型生物材料纳米CS/PCL，以促进成纤维细胞的生长速率。这项工作阐明了一种用于设计组织工程薄膜或支架的新概念——将纳米结构的生物活性生物材料接枝到薄膜或支架上以促进细胞生长。
