Holotomography

Abstract

Holotomography (HT) represents a 3D, label-free optical imaging methodology that leverages refractive index as an inherent quantitative contrast for imaging. This technique has recently seen notable advancements, creating novel opportunities for the comprehensive visualization and analysis of living cells and their subcellular organelles. It has manifested wide-ranging applications spanning cell biology, biophysics, microbiology and biotechnology, substantiating its vast potential. In this Primer, we elucidate the foundational physical principles underpinning HT, detailing its experimental implementations and providing case studies of representative research employing this methodology. We also venture into interdisciplinary territories, exploring how HT harmonizes with emergent technologies, such as regenerative medicine, 3D biology and organoid-based drug discovery and screening. Looking ahead, we engage in a prospective analysis of potential future trajectories for HT, discussing innovation-focused initiatives that may further elevate this field. We also propose possible future applications of HT, identifying opportunities for its integration into diverse realms of scientific research and technological development. Holotomography is a 3D, label-free optical imaging method for visualizing living tissues and cells. In this Primer, Kim et al. discuss the implementation of holotomography in various applications ranging from cell biology to biophysics and biotechnology.