Macroscopic Self-Assembly Based On Biotin-Avidin And S-S Bond

Supramolecular interactions and the formation of covalent bond is performed primarily means of self-assembly. The supramolecular assembly is founded on the basis of weak intermolecular interaction. It is a facile and fast method to achieve a large number of building blocks through assembling under mild conditions, with controllable thickness, shape, composition, leading the supramolecular assembly towards industrialization. However, there remain challenges in the supramolecular assembly, such as too-weak interaction, biological toxicity of host and guest molecules, and mutual interference between different supramolecular forces. So we selected biocompatible biotin/avidin system and reversible S-S bond that is responsive to redox reaction as the macroscopic self-assembly forces. As the strongest non-covalent bod, biotin/avidin performed specificity and good biocompatibility simultaneously, and this enables it to be applied in the construction of biocompatible tissue; moreover, the redox reaction-responsibility of S-S bond makes it possible to realize reversible assembly/disassembly of macroscopic building btocks and achieve stable assembly through strong covalent bond. Therefore, we used cysteine, which contains a thtol group with good biocompatibility as the functional molecule. The current system provides a way to build a biocompatible tissue engineering scaffolds.In this thesis, we firstly prepared PDMS cubes as building blocks for macroscopic self-assembly; meanwhile, polyelectrolytes, PAH-Biotin and PAH-SH were then synthesized through amidation graft reaction with catalytic activation of EDC/NHS in the aqueous phase. Secondly, we modified PDMS with functional groups through layer-by-layer method. Under certain conditions, macroscopic self-assemblies were obtained. The current system offers a new direction to achieve biocompatibility, reversible, stable, highly selective macroscopic self-assemblies.