云母晶面上准外延生长的胶原蛋白纳米线阵列的性质研究

胶原蛋白纤维与同样具有周期性结构表面的羟磷灰石等矿物质晶体能够通过多种作用在介观尺度上相互识别,从而有效地进行规范骨骼、牙齿等器官生长的生物矿化.在本研究中,反相利用生物矿化原理,开发出一种与热壁外延生长(Hot wall epitaxy)技术效果相似的生物大分子纳米线阵列的简单制备技术,成功地将5～10 μg/mL的天然I型鼠尾胶原蛋白单体溶液在云母晶体的(001)晶面上培育成取向单一且长程有序的胶原蛋白纳米线阵列.原子力显微镜实验结果表明,纳米线阵列随胶原蛋白单体浓度增大而变得致密,但是单条纳米线的宽度与高度较为稳定,分别约为60.0和1.5 nm.有纳米线覆盖的云母晶面亲水性好,晶面接触角由25.8°降为9.5°.基于电子背面散射衍射和透射电子显微镜的分析表征结果,纳米线的取向应沿云母110]方向, 更详实地验证了胶原蛋白纳米线的准外延生长机理.

Investigation on Properties of Collagen Nanowires Quasiepitaxially Grown on Mica Lattice Plane

Collagen fibrils and hydroxyapatite might recognize each other at the mesoscale by multiple cooperative interactions due to their intrinsically repetitive structured surfaces, and thus effectively directing the biomineralization, a biological process involving regulating the growth of bones, teeth and other organs. In this work, we developed a simple technique to prepare nanowire arrays of biological macromolecules by reversely using the biomineralization mechanism, with results similar to the hot wall epitaxy, a molecular beam deposition technique under vacuum. With this technique, we successfully cultured 5-10 μg/mL rat tail type I collagen monomer solutions into collagen nanowire arrays on the mica (001) lattice plane along one unique direction across the whole cleavage surface. The atomic force microscope experiments indicated that the nanowires in the arrays became more crowded with higher monomer concentration, but their width and height remained unchanged, about 60.0 nm and 1.5 nm, respectively. The collagen nanowire coating enhanced the hydrophilicity of the mica surface, reducing the contact angle from 25.8° to 9.5°. Based on the characterization results of electron back scattering diffraction and transmission electron microscope, the collagen nanowires were most likely to be oriented along the mica 110] direction, which validated the quasiepitaxial growth mechanism in more details.