“Writing” Crystal Phases in Amorphous Calcium Carbonate via Bio-Inspired Laser-Induced Patterned Transformations

Biomineralization demonstrates nature's remarkable ability to precisely regulate mineral formation, controlling both polymorph selection and spatial organization. This fascinating level of precision has inspired our investigation into spatially controlled, laser-induced crystallization. To this end, we employed laser-induced patterned crystallization within a Mg-stabilized amorphous calcium carbonate (ACC) matrix, generating four distinct phases: calcite, stable dehydrated ACC, monohydrocalcite, and hydromagnesite. We investigated the parameters affecting phase formation and determined that it is governed by laser power and scanning rate. Our calculations allowed us to determine the temperature generated under these conditions, spanning a range of laser powers and scan rates, leading to the development of a model explaining the formation of each phase. This allowed us to reproducibly "write" crystal phases on the surface in a spatially controlled and rationally designed manner. This research presents a novel approach to laser-induced spatial patterning of multiple crystallographic phases through an amorphous precursor, opening new avenues for bio-inspired studies and offering fresh insights into crystallization mechanisms from amorphous precursors.