Characterization of mineralized tissues by atom probe tomography

Mineralized tissues sustain motility, feeding, defense, sensory functions, and even structural color. Their intricate and hierarchical structure is integral to their remarkable mechanical properties. However, our understanding of compositional gradients has been lagging, primarily due to the small characteristic length scales of the fundamental building blocks, presence of elements with low atomic number, and high sensitivity to radiation damage. Laser-pulsed atom probe tomography (APT), a three-dimensional analytical technique with near-atomic spatial resolution and sensitivity approaching the physical limit, has emerged as a transformative technique in this space. Herein, we discuss the principles of operation and sample preparation and highlight its recent application to map the composition of mineralized tissues across complex organic–inorganic, all-inorganic, and tissue-implant interfaces. We further discuss considerations for using APT effectively with complementary techniques and highlight exciting developments that may soon transform our understanding of the formation and properties of mineralized tissues.