Katti Kalpana S, Katti Dinesh R, Dash Rajalaxmi
Department of Civil Engineering, North Dakota State University, Fargo, ND 58105, USA.
Biomed Mater. 2008 Sep;3(3):034122. doi: 10.1088/1748-6041/3/3/034122. Epub 2008 Sep 3.
Recently, biopolymer-based nanocomposites have been replacing synthetic polymer composites for various biomedical applications. This is often because of the biocompatible and biodegradable behavior of natural polymers. Several studies have been reported pertaining to the synthesis and characterization of chitosan(chi)/montmorillonite(MMT) and chitosan (chi)/hydroxyapatite (HAP) for tissue engineering applications. In the present work, a biopolymer-based novel nanocomposite chitosan/montmorillonite (MMT)/hydroxyapatite (HAP) was developed for biomedical applications. The composite was prepared from chitosan, unmodified MMT and HAP precipitate in aqueous media. The properties of the composites were investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Nanomechanical properties were measured using nanoindentation. Cell culture experiments were also conducted in order to ascertain the biocompatibility of the composite. The XRD results indicate that an intercalated structure was formed with an increase in d-spacing of montmorillonite. FTIR studies provide the evidence of molecular interaction among the three different constituents of the composite. AFM images show well-distributed nanoparticles in the chitosan matrix. The composites also exhibit a significant enhancement in nanomechanical property as compared to pure chitosan as well as the chi/HAP and chi/MMT composites. The TGA results indicate that an intercalated nanocomposite was formed with improved thermal properties even compared to chi/MMT composites. The results of cell culture experiments show that the composite is biocompatible and has a better cell proliferation rate compared to chi/HAP composites. This work represents the design of a novel clay-chitosan-hydroxyapatite composite with improved mechanical properties that has potential applications in bone tissue engineering.
近年来，基于生物聚合物的纳米复合材料已在各种生物医学应用中取代了合成聚合物复合材料。这通常是由于天然聚合物具有生物相容性和可生物降解性。已有多项关于壳聚糖（chi）/蒙脱石（MMT）和壳聚糖（chi）/羟基磷灰石（HAP）用于组织工程应用的合成与表征的研究报道。在本研究中，开发了一种基于生物聚合物的新型纳米复合材料壳聚糖/蒙脱石（MMT）/羟基磷灰石（HAP）用于生物医学应用。该复合材料由壳聚糖、未改性的MMT和HAP沉淀在水性介质中制备而成。使用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、原子力显微镜（AFM）和热重分析（TGA）对复合材料的性能进行了研究。使用纳米压痕测量纳米力学性能。还进行了细胞培养实验以确定复合材料的生物相容性。XRD结果表明形成了插层结构，蒙脱石的d间距增加。FTIR研究提供了复合材料三种不同成分之间分子相互作用的证据。AFM图像显示壳聚糖基质中纳米颗粒分布均匀。与纯壳聚糖以及chi/HAP和chi/MMT复合材料相比，该复合材料的纳米力学性能也有显著提高。TGA结果表明形成了插层纳米复合材料，甚至与chi/MMT复合材料相比，其热性能也有所改善。细胞培养实验结果表明，该复合材料具有生物相容性，与chi/HAP复合材料相比，细胞增殖率更高。这项工作代表了一种具有改进机械性能的新型粘土-壳聚糖-羟基磷灰石复合材料的设计，该复合材料在骨组织工程中具有潜在应用。
