Tan Rongwei, Niu Xufeng, Gan Shaolei, Feng Qingling
Department of Materials Science and Engineering, Tsinghua University, Beijing, China.
J Mater Sci Mater Med. 2009 Jun;20(6):1245-53. doi: 10.1007/s10856-009-3692-6. Epub 2009 Mar 9.
Hydrogels are increasingly used in medicine due to their potential to be delivered into the body in a minimally invasive manner and to be gelated at the site of introduction subsequently. The aim of this study was to develop a novel injectable and in situ-forming gel composite (GC) comprised of calcium alginate hydrogel and nano-hydroxyapatite/collagen (nHAC), assess its rheological, mechanical and in vitro degradable properties, and discuss the gelation mechanism. Injectable property test showed that the injectability of GC was tunable. Rheological results indicated that three phases of pre-gel, sol-gel phase transformation and post-gel could be found in the process of gelation. The compressive elastic modulus (E) and shear modulus (G) are in the range of 17.0-56.0 kPa and 24.7-55.0 kPa, respectively. During the in vitro degradation, the wet weight increased in the first week, then declined in the following 3 weeks, but the dry weight lost continuously during whole study. Meanwhile, the surface changed greatly after 2 weeks, but samples did not break down up to 28 days. These data indicate that GC exhibits controllable initial setting time and final setting time, tunable injectability, which provides a possible injectable material for bone repair and bone tissue engineering.
水凝胶因其能够以微创方式注入体内并随后在引入部位凝胶化的潜力而在医学中越来越多地得到应用。本研究的目的是开发一种由海藻酸钙水凝胶和纳米羟基磷灰石/胶原蛋白（nHAC）组成的新型可注射原位形成凝胶复合材料（GC），评估其流变学、力学和体外降解性能，并探讨凝胶化机制。可注射性能测试表明GC的可注射性是可调的。流变学结果表明，在凝胶化过程中可发现预凝胶、溶胶-凝胶相变和凝胶后三个阶段。压缩弹性模量（E）和剪切模量（G）分别在17.0 - 56.0 kPa和24.7 - 55.0 kPa范围内。在体外降解过程中，湿重在第一周增加，随后在接下来的3周下降，但干重在整个研究过程中持续减少。同时，2周后表面变化很大，但样品直至28天均未分解。这些数据表明GC具有可控的初始凝固时间和最终凝固时间、可调的可注射性，为骨修复和骨组织工程提供了一种可能的可注射材料。
