A CaCO₃ Nanograss Interface Grown Via Dynamic Crystalization From Layer-by-layer Matrix

Biomineralization holds tremendous potential in generating complex structures and various functions in organisms,evidenced by the various and versatile inorganic functional structures,such as teeth and bones,in biological systems.The polymorphic appearance and multi-structural nature of CaCO₃ has generated wide research interests.Although the dynamic processes of CaCO₃ crystallization has been widely studied,harnessing this process to achieve complex artificial materials that mimic biological complicated structures and serve appealing functions remains challenging.Previous CaCO₃-based functional materials largely focused on the sustained/responsive releases or organic composites with enhanced mechanical properties.The delicate yet complex structural evolution of CaCO₃ remains underdeveloped with regard to achieving artificial materials.In order to fully exploit the potential of CaCO₃ crystallization in the preparation of artificial materials,we have developed a strategy to prepare CaCO₃ nanograss at the interface by utilizing the dynamic morphological changes of CaCO₃ during crystallization formation.Controllable preparation of the nanoscale CaCO₃ structure is achieved by rapid precipitation in the interfacial organic matrix followed by a slow crystallization process.The key factor during aging is to control the proper humidity.The paper studied in detail the mechanism of CaCO₃ nanograss formation.Finally,the thin layer alginate hydrogel was anchored to the surface of the substrate by utilizing the special morphology and composition characteristics of CaCO₃ nanorass.The highly biocompatible alginate-hydrogel layer prepared on the surface of the medical catheter is capable of reducing damage during simulated cannulation.The research content of this thesis includes the following aspects:?1?Preparation of polyelectrolyte polyamine-polyacrylate multilayer film.The multilayer self-assembly technique was used to prepare multilayer films using polyacrylic acid and acrylamide salts as building blocks.The stability of the films was improved by covalent crosslinking method,and the effect of crosslinking degree on membrane permeability was investigated.?2?Control?PAH/PAA?_6.5 multilayer membrane cross-linking degree as a substrate,grow calcium carbonate on it,adjust crystal growth parameters such as environmental humidity,initial feed concentration and other parameters to regulate the mineralization morphology of calcium carbonate,and explore the crystal Growth mechanism.?3?Using the morphological characteristics of acicular calcium carbonate,the calcium carbonate mineralized layer is used as a calcium source to crosslink a layer of sodium alginate hydrogel,and the human lung fibroblasts are coated in a hydrogel for three-dimensional culture;The gel-calcium carbonate mineralized layer system was modified on the surface of the medical catheter to reduce frictional damage in simulated cannula experiments.