Spiers Memorial Lecture: A retrospective view on the non-classical features revealed by advanced imaging of biominerals

Biominerals have unique morphologies and complex hierarchical microstructures, so the study of biomineralization has benefited greatly from the development of advanced microscopy and characterization tools. In my career, I witnessed a revolutionary change in the theories relating to biomineral formation mechanisms. While much of this was due to the advancements in imaging techniques, I present an argument to suggest that <i>in vitro</i> model systems played an important role in steering the biomineral community toward resolving the non-classical crystallization processes that are now understood to lie at the foundation of biological calcification processes. This retrospective review will discuss two case studies that are classic examples of biominerals, mollusk nacre for the invertebrates, and bone for the vertebrates. It will therefore be biased given my group's discovery of the Polymer-Induced Liquid-Precursor (PILP) process, which serendipitously emulated the morphologies and textures of these (and other) biominerals. The goal, however, is not to repeat that body of literature, but rather to demonstrate how the use of model systems has helped decipher mineralization mechanisms, and to propose new ideas that could be explored to further advance the field.