Abstract
- •Problem: Medium exchange in 3D cell culture is challenging because conventional approaches risk tissue loss and often leave a high residual volume.
- •Manual work is error prone, time consuming, and operator dependent.
- •Solution: Our automated media exchange workflow for spheroids uses peristaltic pumping to minimize tissue loss and residual volume.
- •Results: No tissue loss was observed when exchanging medium for fatty liver tissues with low density and with only 5 µL residual volume in Akura™ 384 microplates.
Approach
- •The full workflow is automated on Integra's WELLJET Dispenser Stacker and coordinated with ADDIMUS hardware and InSphero Akura™ plates.
- •Old medium is gently aspirated through eight angled metal tips of an ADDIMUS washing cassette and pumped into waste through passive valving while the medium line is closed.
- •Fresh medium is dispensed against the wall of the well in an InSphero Akura™ plate while the waste line is closed, enabling controlled exchange near the SureChange ledge.
Results
- •Residual volume was reduced to 5 µL by optimizing needle geometry, needle position, and pumping speed, compared with the much higher residual volume commonly seen in standard U-bottom plates.
- •No tissue loss was observed, and tissue integrity was confirmed for multiple spheroid types in both Akura™ 96- and 384-well-plates.
Joint system for media exchange comprising INTEGRA WELLJET, ADDIMUS washing cassette, and InSphero Akura™ plates
Fig. 1: INTEGRA's WELLJET Dispenser Stacker
Fig. 2: ADDIMUS's washing cassette incl. passive valving
Fig. 3: InSphero's Akura™ plate with cassette nozzle
Automated workflow for low-residual-volume media exchange
Fig. 4: Medium is aspirated gently, the needle is flushed with fresh medium at waste, then moved to the well wall to dispense fresh medium until exchange is complete.
Residual volume optimization and tissue integrity
Fig. 5: Residual volume in Akura™ 384-well plate
Fig. 6: Spheroids of liver tissues, high fat content (left) and low fat content (right)
