Business Development Manager SEED Biosciences Epalinges, Vaud, Switzerland
Abstract: Spheroids offer immense potential in various fields such as drug discovery, personalized and regenerative medicine. Their 3D conformation not only allows extensive molecular signaling among cells and with the extracellular matrix, but also the formation of nutrients and oxygen gradients. Spheroids also regulate drug penetration thanks to the presence of permeability barriers. They thus mimic the complexity of tissues and tumor environment better than traditional two-dimensional cell cultures.
Obtaining consistent spheroid assay outcomes necessitates the capability to pre-select them based on their size as well as the capability to isolate them in different plate formats. Accessible solutions for manipulating and isolating spheroids remain limited. Currently, the industry standard for handling organoids and spheroids involves manual processes that are cumbersome and not very efficient in throughput, hardly reproducible and slow. On the other hand, more complex, specialized equipment may not be readily accessible and is highly expensive.
Using impedance-based dispensing technology together with an advanced data analysis software, Dispen3D stands out as an ideal platform for characterizing and isolating individual spheroids.
Here we present a simple and efficient workflow for the isolation of single spheroids in multiwell plates using Dispen3D. Spheroids with a diameter of 110 to 175 µm were isolated individually in a 96 well plate in 6 minutes with an efficiency of 93%. The reliability of the impedance signal as a proof of single-spheroid isolation was above 97%. A positive correlation of 0.87 was observed between spheroid impedance value obtained during isolation and their area measured after microscopy imaging. This highlights the use of the impedance measurement as a tool to select spheroids based on their size. Compared to the classical limiting dilution workflow, Dispen3D allowed a 2.5 fold enrichment in single spheroid isolation. Moreover spheroid integrity was conserved after isolation with Dispen3D and a 4.7X increase in spheroid diameter was observed after 11 days of culture. This growth was similar to the one observed for the spheroids isolated using limiting dilution.
In addition to being intuitive and compact, Dispen3D is therefore a versatile tool for fast, gentle and traceable spheroid isolation. There is no need for instrument maintenance, or calibration thanks to the use of disposable tips that avoid cross-contamination. Allowing the isolation of cellular aggregates ranging from 90 µm to 200 µm, it will be interesting to explore the use of Dispen3D for the isolation of other 3D cellular models such as organoids and tumoroids.
