鸟嘌呤的生物矿化及其仿生矿化合成

The biomineralization mechanism of biological guanine crystals with highly ordered hierarchical microstructures in fish skins are to be investigated in this work. The formation mechanism for the biological guanine crystals, the relationship of the microstructures and the polarized reflective spectra of the narrowband and tunable reflectors (skins from neon tetra fish) and broadband reflectors (scales, skins from Koi fish and hairtail fish) are to be studied in details in this project. Inspired by the exquisite control on the size、polymorph、morphology of biological guanine crystals with controlled reflective properties, guanine single crystalline platelets in beta phase similar to biological guanine crystals are to be synthesized in the laboratory by using amorphous phase as crystallization precursor and macromolecules as additives. Furthermore, small biological molecules such as xanthine, hypoxanthine, and uric acid are to be occluded in the guanine single crystalline platelets. Layer membranes with highly ordered hierarchical microstructures which are composed of guanine micro- and nano- platelets with high refractive index and macromolecules with low refractive index are to be synthesized and applied as high reflective layer-like thin membrane materials.

由于鸟嘌呤的高折射指数，生物组织中的鸟嘌呤多级有序结构具有很强的操控光的能力。本项目将以生物体内2类代表性的多层鸟嘌呤生物晶体：具有光控变色和窄波段反射特性的高有序度鸟嘌呤多层微纳结构（霓虹灯鱼的鱼皮）、具有宽波段反射特性的低有序度鸟嘌呤多层微纳结构）（鲤鱼、带鱼的鱼皮和鱼鳞）为研究对象，研究这类与细胞质在生物体内共同组成多层微纳结构的鸟嘌呤有机晶体的形成过程和矿化机理，研究生物鸟嘌呤多层有序微纳结构特点与其特定波段下的高反射性能的关系。受生物鸟嘌呤矿化机理的启发，以非晶态组分为晶化前驱体，借助大分子添加剂的诱导和调控作用，实现鸟嘌呤多级有序微纳结构的可控晶化，获得晶型、尺寸、暴露晶面可控的片状鸟嘌呤单晶的可控合成，在单晶片中掺杂次黄嘌呤等生物小分子，进一步实现基于鸟嘌呤片状晶体的多层有序组装薄膜，制备出具有高反射率的薄膜材料。

系统研究了扇贝眼睛凹面镜区域鸟嘌呤的生物矿化机制，探究了鱼鳞中的有机分子对鸟嘌呤晶化过程的影响，发现扇贝眼睛鸟嘌呤先形成非晶态鸟嘌呤，再形成单晶鸟嘌呤纳米片，进而形成鸟嘌呤纳米片孪晶。而鱼鳞中有机分子对无水鸟嘌呤单晶纳米片的合成具有重要的作用，可以稳定(100)晶面。借助大分子添加剂的诱导和调控作用，获得晶型、尺寸、暴露晶面可控的片状鸟嘌呤相单晶的可控合成，并在鸟嘌呤单晶片中掺杂生物小分子。成功实现对鸟嘌呤片晶的仿生可控合成，实现暴露高折射指数（100）晶面的beta相无水鸟嘌呤纳米片，得到具有优异珠光色的人工鸟嘌呤珠光颜料。这是首次获得有机小分子晶体纳米珠光颜料，拓展合成出另外3类具有特定功能的鸟嘌呤材料，包括具有高度紫外光稳定性和珠光特性的多种染料分子掺杂的彩色鸟嘌呤珠光颜料，以及荧光分子掺杂的荧光鸟嘌呤珠光颜料，将仿生合成的鸟嘌呤纳米片晶进行多层有序组装，得到具有高反射率的减偏振薄膜材料。