Optical micromanipulation of nanoparticles and cells inside living zebrafish

TLDR

Biological regulation depends on physical interactions between cells and their microenvironment, yet micromanipulation has largely been limited to in vitro systems that fail to capture the complex in vivo context of multicellular organisms. The study aims to employ high‑precision micromanipulation to map cellular interactions and to screen nanoparticle‑cell interactions for cancer therapy and infection biology. Using optical tweezers, the authors perform micromanipulation throughout the transparent zebrafish embryo, controlling interaction duration, position, and magnitude. The technique traps diverse cells, nanoparticles, and bacteria, enabling analysis of endothelial and macrophage adhesion and membrane deformation, and yields direct insights into cell interactions inaccessible with current methods.

Abstract

Regulation of biological processes is often based on physical interactions between cells and their microenvironment. To unravel how and where interactions occur, micromanipulation methods can be used that offer high-precision control over the duration, position and magnitude of interactions. However, lacking an in vivo system, micromanipulation has generally been done with cells in vitro, which may not reflect the complex in vivo situation inside multicellular organisms. Here using optical tweezers we demonstrate micromanipulation throughout the transparent zebrafish embryo. We show that different cells, as well as injected nanoparticles and bacteria can be trapped and that adhesion properties and membrane deformation of endothelium and macrophages can be analysed. This non-invasive micromanipulation inside a whole-organism gives direct insights into cell interactions that are not accessible using existing approaches. Potential applications include screening of nanoparticle-cell interactions for cancer therapy or tissue invasion studies in cancer and infection biology.