Nacre is expected to be transformed into artificial bone, with rapid cultivation achieved in the laboratory
The research group of Professor Yu Shuhong at the University of Science and Technology of China has for the first time prepared an artificial biomimetic structural material by simulating the natural growth process of nacre, with characteristics such as chemical composition and microstructure highly similar to natural nacre, and with good strength and toughness at the same time. The results were published in the recently released American journal Science.
The nacre in the inner layer of shells has a unique and complex microscopic layered structure. This structure gives nacre both extraordinary hardness and toughness at the macroscopic level, two properties that cannot be achieved simultaneously in many synthetic materials.
Yu Shuhong's team first used directional freezing and acetylation conversion methods to build a similar layered "framework" using the exact same organic material found in natural shells, and placed it into an artificial "chamber." Unlike in nature, where shellfish spend several years continuously secreting this organic substance and causing calcium carbonate to mineralize on its framework, Yu Shuhong's team designed a "circulatory system," that is, through a peristaltic pump functioning similarly to the human heart, continuously pumping saturated calcium bicarbonate solution into the framework inside the chamber while carrying out the residual waste after the reaction. Within two weeks, it could "replicate" the natural formation process of nacre that takes several years, at a speed more than a hundred times faster. Various detection methods such as electron microscopy showed that this artificial material, prepared through a material growth method highly similar to natural strategies, is highly similar to natural nacre in composition and microstructure, reproduces the microscopic hierarchical structure and mechanical properties of natural nacre at multiple scales, and also exhibits good strength and toughness at the macroscopic level.
Professor Yu Shuhong introduced that the development process of human bones and teeth is strikingly similar to the formation process of nacre, with the difference being that the main component of mineralization is hydroxyapatite rather than calcium carbonate. Using a similar strategy to synthesize artificial bones or teeth is expected to highly reproduce the strength and toughness of human bones, and because the composition is highly similar, it can effectively avoid rejection reactions when the material is implanted into the human body, and also eliminate the pain of having metal components placed in the human body and then removed later. (Reporter Wu Changfeng)