Join us on a journey through groundbreaking scientific exploration as we introduce a series of 6 publications showcasing the unparalleled capabilities of the Tomocube Holotomography system in lipid analysis-related research. 

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1. Noninvasive morpho-molecular imaging reveals early therapy-induced senescence in human cancer cells 
Science Advances 2023, 25(37); https://doi.org/10.1126/sciadv.adg6231 

Application: Cancer biology. Utilized equipment: HT-2H  

Given that standardized anticancer treatments produce only limited effective clinical outcomes, this study offers hope for optimizing therapeutic decision-making in oncology by introducing a label-free, rapid, and accurate therapy screening method to increase treatment efficacy. 

In terms of lipid profiling, therapy-induced senescent (TIS) cells were monitored at their early and late stages from Day 0 to Day 7 using Holotomography. As a result, researchers found significant changes unique to their phenotype compared to untreated proliferating cancer cells with only a few lipid droplets at all examined time points, TIS cells exhibited several overproduced lipid regions with clear lipid accumulation over the progression of the treatment. More specifically, while senescent cells had a relatively constant lipid dry mass–to–volume ratio, untreated cells formed lipid droplets that gradually became denser over time.

By exploiting Holotomography, a label-free, quantitative, rapid, and easy-to-use technology, this study achieved a comprehensive lipid profile of TIS over early reprogramming while dismissing the potential artifact due to labeling and/or manipulating cells in standard analyses. 
 

2. Lack of Nck1 protein and Nck-CD3 interaction caused the increment of lipid content in Jurkat T cells 
BMC Molecular and Cell Biology 2022, 23(36); https://doi.org/10.1186/s12860-022-00436-3 

Application: Cell biology, Immunology. Utilized equipment: HT-2H 

This research paper investigates the effect of the non-catalytic region of tyrosine kinase (Nck) and Nck-CD3 interaction on lipid metabolism in Jurkat T cells. It was shown that Nck1 knockout and Nck-CD3 interaction hindrance led to irregular cellular shapes with increased lipid content, greater lipid mass/cell mass ratio, and upregulated lipid metabolite compared to control cells. 

This study also highlighted holotomography, a 3D quantitative phase imaging technology that provides label-free high-resolution images of living cells, as a valuable research tool to assess the lipid profile of Jurkat T cells through 3D visualization of label-free specimens and lipid quantification. 
 

3. Interactions of Nanoparticles with Macrophages and Feasibility of Drug Delivery for Asthma 
Int. J. Mol. Sci. 2022, 23(3), 1622; https://doi.org/10.3390/ijms23031622 

Application: Immunology, Nanomaterials. Utilized equipment: HT-2H 

In a study designed to understand the interaction between nanoparticles and immune cells, researchers observed remarkable changes in subcellular lipid droplets when nanoparticles were phagocytized by macrophages. This phenomenon again highlighted the important role of lipid metabolism in the immune system, partially through its involvement in regulating macrophage functions.  

This research paper also emphasized holotomography as an advanced imaging tool that provided more intracellular images than other analytical tools. By allowing label-free imaging of living cells with quantitative information, lipid droplet dynamics could be easily observed without the risk of phototoxicity, photobleaching, or crumpling by fixation.  

With holotomography, researchers could confirm the activation of LPS-stimulated macrophages and differentiate them from untreated cells through quantitative information, morphological changes, and the presence of lipid droplets. 
 

4. Label-free tomographic imaging of lipid droplets in foam cells for machine-learning-assisted therapeutic evaluation of targeted nanodrugs 
ACS nano (2020), 14(2), 1856-1865; https://doi.org/10.1021/acsnano.9b07993  

Application: Cell biology, Nanomaterial, Utilized equipment: HT-2H  

The formation of lipid-laden macrophages, also called foam cells, through the over-accumulation of lipids in mammalian macrophages is a hallmark event of early-stage atherosclerotic lesions. It is considered an attractive target for therapeutic intervention in atherosclerosis. Therefore, subcellular lipid droplet (LD) detection and monitoring are critical in investigating lipid metabolism-related disease mechanisms and therapeutic strategies.  

However, these studies are often hindered by the inherent limitations of conventional methodologies. For example, under microscopic observation, lipophilic organic dyes (Nile red, Oil red O) may deform the LD structure via phototoxicity and photobleaching. Meanwhile, label-free imaging techniques such as Raman spectroscopy and 2D QPI either come with spatial resolution limitations or do not allow tomographic investigation.  

In this research paper, holotomography was utilized to identify LDs in foam cells and demonstrated the differentiation of macrophages into foams in living cells in real-time without staining, which could not be achieved using fluorescence microscopy. The therapeutic efficacy of nanodrug was also successfully evaluated by real-time monitoring of biophysical parameters of LDs along with machine learning assistance. 
 

5. Camphene Attenuates Skeletal Muscle Atrophy by Regulating Oxidative Stress and Lipid Metabolism in Rats 
Nutrients 2020, 12(12), 3731; https://doi.org/10.3390/nu12123731 

Application: Cell biology, Immunology. Utilized equipment: HT-2H  

Mitochondrial dysfunction and ROS generation are identified as key contributors in sarcopenia or cachexia-related muscle atrophy progression, leading to oxidative stress and changes in homeostasis.  

Researchers have also reported that lipid accumulation during the onset of the atrophy and skeletal muscle lipid regulation could be a major mechanism for suppressing the progression of it. 

In exploring camphene's protective effects against ROS-induced muscle atrophy, 3D holotomographic observation was performed to elucidate the effect of camphene on H2O2-induced lipid metabolism. The results reveal a significant lipid accumulation in the H2O2-induced group, contrasting with a notable decrease in the other group with the presence of camphene. This research underscores the potential of holotomography in discerning alterations in lipid metabolism dynamics. 
 

6. Intercellular Bioimaging and Biodistribution of Gold Nanoparticle-Loaded Macrophages for Targeted Drug Delivery 
Electronics 2020, 9(7), 1105; https://doi.org/10.3390/electronics9071105 

Application: Cell biology, Immunology, Nanomaterial. Utilized equipment: HT-2H  

Holotomography was utilized as part of the methodology to perform biodistribution imaging in a study aimed at validating the effectiveness of macrophages as a nanodrug delivery system at intercellular and ex vivo levels. The in vitro biodistribution imaging technique enables the analysis of the conjugation degree between the nanoparticles and macrophages. 

Since the emergence of lipid droplets (LDs) is important evidence of the activated macrophage and LDs are highly feeble to light exposure and chemical fixation, holotomography proved to be the most suitable technique for confirming the activation of nanoparticle internalization of macrophages through LD detection. With holotomography, not only can the researchers investigate the dynamic 3D morphology of cells label-free and in real-time but they can also observe subcellular organelles without any label.