Spheroid Cell Aggregation Enhanced by Enzyme-Free Ultrasound-Detached Cells

Spheroids are being widely studied as potential building blocks for complex organ engineering, tools for drug screening and cancer study. However, formation time has become the bottleneck of applications due to the need for large-scale high-quality spheroids production. Formation time is often dominated by ECM construction and not cell aggregation. Therefore, this study focuses on the influence of ultrasound detachment replacing conventional enzyme detachment on spheroid formation processes. Thanks to cell surface protein preservation in ultrasound detachment, cell aggregation time is reduced while decreasing the formation variabilities. Moreover, it is confirmed that cells are intrinsically more capable of aggregating through enzyme-free detachment. On top of that, transplantations into rats showed equally successful engraftment properties for enzyme-free detached cells. Finally, the impact on the real co-cultured spheroid application was shown to be beneficial through more localized cell groups inside of the spheroids, possibly improving therapeutic effects and vascularization. Through this study, it is proved that ultrasound detachment can replace enzyme detachment without degrading the final spheroid properties but reducing the formation time, and variability and improving robustness and cell distribution. This opens up a new range of applications for better and faster spheroid formation in numerous bioengineering applications.