Preclinical drug development relies on advanced in vitro models with a high degree of standardization to achieve maximal predictivity for an efficient compound de-risking strategy. InSphero’s scaffold-free organotypic three-dimensional (3D) microtissue spheroids fulfil these requirements as they can be produced and assayed by standard automated liquid handling systems. The Integra Viaflo 96 Channel Electronic Hand-Held Pipette is perfectly suited to produce 3D microtissues in InSphero’s GravityPLUS™ hanging drop plate and to further culture and process them in the GravityTRAP™ platform. Ease of use, versatile programming, and highly accurate tip positioning are the key advantages of the Viaflo 96 pipette which guarantee to perform medium to high throughput screening campaigns with 3D microtissues successfully and with considerable time savings of up to 40% compared to manual pipetting with an 8-channel pipette.
3D microtissues for the advancement of cell-based assays
3D cell culture enables the investigation of cellular functions that are usually not observable in «petri-dish-based» culture formats. InSphero offers a variety of scaffold-free microtissues derived either from tumor cell lines, primary cells or iPSCs. Theses microtissues display a variety of organotypic features which underscores their biological relevance in predicting drug interaction far better than with commonly used cell monolayers:
• Enhanced formation of cell to cell contacts (tight junctions, desmosomes, etc.)
• Extracellular matrix formation
• Polarization of epithelial cells
• Organotypic cell arrangement in cocultures of parenchymal and nonparenchymal cells
• Altered gene expression profile due to epigenetic regulation
Because of their more pronounced tissue-specific properties and functionality, 3D microtissues are perfectly suited for medium to large scale compound testing as required in the pharmaceutical, cosmetics and chemical industry.
InSphero’s hanging drop microtissue production platform
InSphero’s microtissue production system relies on the hanging-drop cell culture technology, which minimizes the interaction with artificial surfaces and maximizes cell to cell contact mediated by gravityenforced cellular self-assembly. InSphero’s patentpending hanging-drop platform GravityPLUS™ is designed to produce and maintain standardized microtissues in a highly reproducible fashion using standard liquid handling equipment. Each individual well is designed in the shape of two opposed funnel-like structures connected by a capillary, thus creating sufficient adhesive and capillary forces to keep a drop of 35-45 μl stably in place. Microtissues are produced in the GravityPLUS™ plate upon application of a cell suspension of defined cell density from the top. Microtissue formation and maturation in the hanging drop occurs within 2-4 days after seeding depending on cell types used.
GravityTRAP™: 3D microtissue receiver and assay platform
For extended culture periods and downstream processing (compound treatments, assays), the microtissues can be transferred into the GravityTRAP™ format, which is a specifically designed multi-well plate to accommodate microtissues produced in the GravityPLUS™ system. The GravityTRAP™ offers several key advantages for culturing, manipulating and assaying microtissues:
• No attachment to plastic due to non-adhesive coating
• Transparent clear bottom for visual inspection by inverted bright field or fluorescence microscopy
• Safe medium replacement without risk of microtissue loss
The transfer of microtissues from the GravityPLUS™ into the GravityTRAP™ platform can be achieved simply by supplying sufficient medium to the already existing hanging drop, which eventually falls into the well of the aligned GravityTRAP™ underneath carrying along the microtissue.
The above figure illustrates the sequence of 3D microtissue seeding, formation and maturation in the GravityPLUS™ plate with subsequent transfer into the GravityTRAP™ format for long term culture and experimental procedures.
Viaflo Electronic 96 Channel Hand Held Pipette
Viaflo 96 is a 96-channel pipette, which was designed to resemble hand held pipetting and to increase productivity at the same time. The pipette is guided by hand but movements are assisted by motors for effortless and ergonomic working.
Viaflo 96 is used to transfer reagents and samples from a reagent reservoir to 96 and 384 well plates or from plate to plate. Up to 96 samples can be transferred at once.
To reformat 96 well plates to 384 well plates, the plate holder can be shifted to quickly accommodate all wells of a 384 well plate.
Viaflo 96 covers a large volume range of 0.5 μl to 1250 μl with four interchangeable pipetting heads. These heads are changed within seconds to optimally adapt Viaflo 96 to the application currently performed.
For delicate pipetting operations, such as the transfer of microtissues, several user-defined position settings can be used. This allows automatic guidance into the wells but also to set a specific z-height. The z-height sets a minimum height above a plate and assures that all subsequent transfers are performed at the same height to guarantee highly reproducible pipetting results.