Atom probe tomography for biomaterials and biomineralization

Abstract

Natural and synthetic biomaterials are part of our daily lives, from our own skeleton and teeth to coral reefs and carbon-capturing single-cell organisms in the oceans, to engineered ceramics and minerals comprising our toothpaste and bone replacements. Many natural biomaterials are hierarchically structured with remarkable material properties that arise from their unique combination of organic and inorganic components. Such structural hierarchy is often formed and developed through a process of biomineralization. Many fundamental questions remain regarding mineralization in bones, teeth, biomaterials and at biointerfaces, partly due to the challenges in characterizing three-dimensional (3D) structure and chemical composition simultaneously at the nanometer scale. Atom probe tomography (APT) is a 3D characterization technique that combines both sub-nanometer spatial resolution and compositional sensitivity down to parts per million. While APT is well-established in application to conventional engineering materials, advances in recent years have seen its expansion into the field of biomineralization research. Here, we focus our review on APT applications to biominerals, biomaterials and biointerfaces, providing a high-level summary of the findings unveiled in biomineralization by APT, as well as a primer on its theory and best practices specific to the biomineralization community. We show that APT is a promising characterization tool already applied to some biomaterials, where its unique ability to quantify 3D chemical composition is not only complementary to other microscopy techniques but could become an integral part of biomaterial research. With the emerging trends of correlative and cryogenic analysis workflows, APT has the potential to improve fundamental understanding of a broader range of biomaterials, while deriving novel perspectives on clinical applications and strategies for functional material design.