Tomocube

Live cell imaging offers real-time insights into cellular responses to diverse stimuli by capturing and recording complex biological processes within living cells. Holotomography enhances this capability by enabling immediate examination without the need for pre-treatment processes and facilitating continuous monitoring of cellular phenomena overtime. This methodology proves invaluable in studying fundamental cellular processes, including cell division, migration, cell interaction, signaling pathways, and cellular responses to drug-induced or environmentally induced changes. The broad applications of this advanced imaging technique span various scientific domains, prominently featuring in cell biology, pharmacology, and diverse biomedical research areas. Its widespread use significantly contributes to a comprehensive understanding of cell function within the natural and dynamic living environment.

Lipid droplets, crucial energy storage organelles for cells, play vital roles in various physiological processes, including those observed in hepatocytes and immune cells. Conventional imaging methods often rely on special dyes like Nile red or BODIFY to visualize transparent lipid droplets, a technique typically limited to fixed cells. Furthermore, dyes for living cells possess relatively low molecular specificity, introducing challenges such as light bleaching and phototoxicity during extended imaging sessions.

HT presents a distinctive advantage by measuring the average refractive index (RI) of each pixel. With the RI of lipid droplets being 1.38 or higher, HT enables effective compartmentalization of lipid droplets in the imaging process.

In a noteworthy study published in ACS Nano in 2020, researchers quantitatively analyzed the suppression of lipid droplet production over time in macrophages and foam cells—key players in arteriosclerosis—when subjected to drug treatments. The analysis involved quantifying various parameters, including the number, volume, and dry mass of lipid droplets, with a comparative assessment between different treatments, particularly in response to nanomaterial treatment (Park et al., 2020). Another study highlighted the potential of HT-X1 products by extensively observing a 42-day process wherein human knee chondrocytes underwent reverse differentiation to form dedifferentiated adipocytes (DFAT) and subsequently re-differentiated into mature adipocytes (Jeong et al., 2024). This application of HT technology allows for detailed and dynamic investigations into lipid droplet dynamics and related cellular processes.

Cell-in-cell (CIC) structures, where one cell engulfs another, creating a unique cellular arrangement, offer insights into cellular behaviors and interactions. HT excels in rapidly capturing three-dimensional shapes without staining, making it ideal for observing diverse cell interactions in their native state. In a recent study, the CIC phenomenon, where NK cells entered cancer cells, was identified using HT imaging (Choe et al., 2022). Utilizing label-free HT observation of CIC structures between cancer and NK cells, the study focused on heterotypic cell segmentation, facilitating a further analysis of its contribution to drug resistance. Continuous monitoring of the time-lapse process of cancer cell death added temporal insights. Incorporating correlative fluorescence imaging aided in distinguishing different cell types, enhancing the understanding of dynamics within cell-in-cell structures.

Cell migration assays in a controlled environment often employ live cell timelapse imaging to study dynamic cellular movements, providing insights into the mechanisms underlying physiological activities like wound healing or cancer cell metastasis. HT emerges as a crucial tool for monitoring fundamental cell behaviors, encompassing proliferation, migration, and spreading.

Migrasomes, formed in migrating cells, are gaining renewed attention in the realm of extracellular vesicles. In a recent study, HT was employed to observe that TNF alpha increased the formation of migrasomes (Gagat et al. 2021). HT played a crucial role in correlating the 3D morphology with localization in correlative fluorescence imaging, enabling stereoscopic observation of migrasomes.