In biomedical research, 3D cell cultures are steadily emerging as more realistic and predictive in vitro model that does not involve the use of animals. However, the large adoption of 3D cell models is still hampered by heterogeneity in culture protocols and the lack of suitable analytic technologies; as a consequence, the results in 3D can be controversial and difficult to interpret. CellDynamics works in this direction: the company develops a flow-based analytic technology, which characterizes 3D cellular models with quantitative biophysical measurements of size, weight, and mass density. Although few prototypical solutions have been presented for single-cell analysis, no similar technologies already exist for characterizing thick 3D models such as spheroids or organoids. The first product launched in the market in January 2021, called the W8 Physical Cytometer (www.celldynamics.it/w8/), represents the only available technology for the biophysical characterization, physical-based sorting, and sterile recovery of sphere-like 3D cell cultures. The system innovatively combines flow-based sample manipulation with a gravimetric and image-based analysis to quantify biophysical observables at 99.9% precision and 99.0% accuracy. The homogeneity of 3D cell cultures, in terms of size, shape, and 3D architecture, can be difficult to achieve, and their generation is often time- and resource-consuming. Usually, when tracking spheroids' growth via imaging analyses, attention is focused on their size- and shape variation over time. However, this approach is not fully representative of 3D models, as spheroids undergo specific compaction processes over time, depending on factors such as cellular heterogeneity, growth environment, and pharmacological treatments. For this reason, the W8 Physical Cytometer empowers researchers with a quality control assay for 3D cell cultures, by gathering precise information on sample biophysics. These features are crucial to optimize protocol standardization and achieve homogeneous and reproducible samples. In addition, variations in mass density, weight, and volume are also connected to changes in the cell cycle, induced by external stimuli. Therefore, the measurement of these biophysical parameters represents a useful tool, both for disease modeling and drug testing. In this regard, the W8 Physical Cytometer provides a label-free, non-destructive assay to evaluate the in vitro efficacy of chemotherapeutics or cell-based therapies (immunotherapy) on 3D cell cultures, without compromising sample viability. Indeed, while weight loss and diameter shrinkage are coherently related to drug-induced apoptosis, mass density represents a valuable marker of the 3D sample’s impaired compactness linked to drug (or immune cells) penetration rate. After the analysis, the sorted and collected samples are prone to be re-plated and exploited for further downstream analysis. This represents a great advantage when compared to more invasive techniques such as super-resolution microscopy, flow cytometry, or immunohistochemistry, which are meant to be end-point assays. To conclude, CellDynamics’ approach shares common goals within the SLAS vision, as an enabling technologies manufacturer for drug discovery in many research fields. The W8 Physical Cytometer method is patent-pending, and three scientific papers are available in the attachments.
