Chesnutt Betsy M, Viano Ann M, Yuan Youling, Yang Yunzhi, Guda Teja, Appleford Mark R, Ong Joo L, Haggard Warren O, Bumgardner Joel D
Biomedical Engineering Department, University of Memphis, Memphis, Tennessee, USA.
J Biomed Mater Res A. 2009 Feb;88(2):491-502. doi: 10.1002/jbm.a.31878.
To meet the challenge of regenerating bone lost to disease or trauma, biodegradable scaffolds are being investigated as a way to regenerate bone without the need for an auto- or allograft. Here, we have developed a novel microsphere-based chitosan/nanocrystalline calcium phosphate (CaP) composite scaffold and investigated its potential compared to plain chitosan scaffolds to be used as a bone graft substitute. Composite and chitosan scaffolds were prepared by fusing microspheres of 500-900 microm in diameter, and porosity, degradation, compressive strength, and cell growth were examined. Both scaffolds had porosities of 33-35% and pore sizes between 100 and 800 . However, composite scaffolds were much rougher and, as a result, had 20 times more surface area/unit mass than chitosan scaffolds. The compressive modulus of hydrated composite scaffolds was significantly higher than chitosan scaffolds (9.29 +/- 0.8 MPa vs. 3.26 +/- 2.5 MPa), and composite scaffolds were tougher and more flexible than what has been reported for other chitosan-CaP composites or CaP scaffolds alone. Using X-ray diffraction, scaffolds were shown to contain partially crystalline hydroxyapatite with a crystallinity of 16.7% +/- 6.8% and crystallite size of 128 +/- 55 nm. Fibronection adsorption was increased on composite scaffolds, and cell attachment was higher on composite scaffolds after 30 min, although attachment rates were similar after 1 h. Osteoblast proliferation (based on dsDNA measurements) was significantly increased after 1 week of culture. These studies have demonstrated that composite scaffolds have mechanical properties and porosity sufficient to support ingrowth of new bone tissue, and cell attachment and proliferation data indicate composite scaffolds are promising for bone regeneration.
为应对因疾病或创伤导致的骨缺损再生挑战，人们正在研究可生物降解支架，作为无需自体或异体移植来再生骨的一种方法。在此，我们开发了一种新型的基于微球的壳聚糖/纳米晶磷酸钙（CaP）复合支架，并研究了其与普通壳聚糖支架相比用作骨移植替代物的潜力。通过融合直径为500 - 900微米的微球制备复合支架和壳聚糖支架，并检测其孔隙率、降解情况、抗压强度和细胞生长情况。两种支架的孔隙率均为33 - 35%，孔径在100至800之间。然而，复合支架表面粗糙得多，因此单位质量的表面积比壳聚糖支架多20倍。水合复合支架的压缩模量显著高于壳聚糖支架（9.29±0.8兆帕对3.26±2.5兆帕），并且复合支架比其他壳聚糖 - CaP复合材料或单独的CaP支架更坚韧、更具柔韧性。通过X射线衍射显示，支架含有部分结晶的羟基磷灰石，结晶度为16.7%±6.8%，微晶尺寸为128±55纳米。复合支架上纤连蛋白的吸附增加，30分钟后复合支架上的细胞附着更高，尽管1小时后的附着率相似。培养1周后成骨细胞增殖（基于双链DNA测量）显著增加。这些研究表明，复合支架具有足以支持新骨组织向内生长的机械性能和孔隙率，细胞附着和增殖数据表明复合支架在骨再生方面很有前景。
