Manual medium exchange for spheroids and organoids in 96- and 384-well plates
A practical guide to gentle manual medium exchange for spheroids, organoids, and other fragile 3D cell cultures in 96- and 384-well plates. The practical challenge is that the biology is often only weakly constrained by gravity, plate geometry, self-aggregation, or extracellular matrix support. A small change in tip position or aspiration speed can turn a routine 3D cell culture medium change into spheroid loss, organoid loss, dome disruption, or avoidable well-to-well variability.
The safest manual medium exchange methods are designed around one principle: reduce local flow around the 3D culture. In practice, that means gentle aspiration, sidewall positioning, controlled refill, and a deliberate residual volume instead of chasing complete liquid removal.
Why manual medium exchange is difficult in 3D cultures
Spheroids, organoids, tumoroids, microtissues, and ECM-embedded organoids do not behave like adherent monolayers. Many are not firmly attached to the well bottom, and some are supported by Matrigel, Geltrex, Cultrex, or another hydrogel dome that can be deformed or dried out during liquid handling.
Loss usually comes from a local fluid-handling problem rather than the nominal exchange volume alone. The highest-risk situations are central aspiration, deep tip placement, high aspiration speed, forceful refill from above, plate movement, and variable technique across wells.
- Free-floating spheroids can move toward the pipette if suction is too close.
- Fragile organoids can fragment when exposed to fast local flow.
- ECM-embedded organoids can be damaged if the matrix dome is touched or allowed to dry.
- Small 384-well volumes leave less margin for inconsistent tip depth or angle.
Manual workflow for gentle aspiration and refill
- Let the plate settle flat before handling so spheroids or organoids return to their expected position.
- Place the pipette tip at the sidewall, away from the 3D culture. In plates with a dedicated exchange ledge, use that feature.
- Aspirate slowly and stop before the culture, dome, or bottom of the well is exposed to direct suction.
- Leave a defined residual volume that protects the culture from drying and abrupt fluid movement.
- Add fresh medium at the sidewall so the liquid climbs the wall and spreads into the well instead of hitting the culture as a jet.
- Keep tip depth, angle, aspiration speed, refill speed, and timing consistent across the full plate.
For a deeper discussion of spheroid and organoid retention during medium change, see the related ADDIMUS BIO guide on changing medium without losing 3D cultures.
Starting points for 96-well and 384-well plates
| Format | Initial tip strategy | Residual volume strategy | What to watch |
|---|---|---|---|
| 96-well spheroid plates | Sidewall, away from the center | Start conservatively and reduce only after retention is stable | Loose spheroids, newly formed aggregates, and plate movement |
| 96-well organoid workflows | Sidewall, away from organoids or matrix | Leave enough medium to avoid drying or direct suction | Irregular organoid fragments and ECM dome integrity |
| 384-well spheroid or organoid plates | Sidewall with tightly controlled depth | Use a larger safety margin until the method is validated | Small volume errors, fast local flow, and edge effects |
| Specialized plates with exchange ledges | Exchange ledge | Lower residual volumes may be possible after validation | Whether the aspiration point stays separated from the culture position |
Additional care for ECM-embedded organoids and Matrigel domes
Organoid medium exchange is not always the same as spheroid medium exchange. Free-floating organoids may behave like spheroids, but ECM-embedded organoids add another constraint: the matrix must remain intact, hydrated, and mechanically undisturbed.
- Do not place the tip next to or inside the Matrigel dome.
- Do not aspirate until the dome is exposed to air.
- Dispense medium gently at the sidewall, not directly onto the dome.
- Validate the method for the matrix volume, well geometry, and organoid size distribution.
If your workflow also includes dome placement, the related ADDIMUS BIO guide on dispensing Matrigel domes in 96-well plates covers temperature control, dome shape, and gentle medium addition.
Common mistakes that increase spheroid or organoid loss
- Placing the tip centrally above the spheroid, organoid, or dome.
- Aspirating quickly to shorten the manual workflow.
- Trying to remove every last microliter before the culture is stable.
- Changing tip depth or angle from column to column.
- Refilling directly onto the 3D culture instead of along the well wall.
- Using a 96-well method unchanged in 384-well plates.
A technically successful method is not just one that retains cultures in a few wells. It should be repeatable across the full plate, across operators, and across repeated medium exchange cycles.
When manual technique becomes the limiting factor
Manual medium exchange can work well during method development, pilot experiments, and low-throughput culture maintenance. It becomes harder to standardize when plate counts rise, when 384-well plates are introduced, or when fragile 3D cultures need repeated medium exchange over time.
At that point, the relevant question is not only whether medium can be exchanged, but whether the process can be repeated with the same residual volume, aspiration position, timing, and refill behavior across many wells.
For laboratories that need more standardized medium exchange in spheroid and organoid workflows, ADDIMUS BIO develops WASH+ add-on solutions for gentle automated liquid handling on established bulk dispensers.
Summary
Manual medium exchange for spheroids and organoids is safest when it is treated as a controlled liquid-handling step. Keep the plate stable, aspirate from the sidewall or exchange ledge, leave a protective residual volume, and refill gently along the wall.
For 384-well plates and ECM-embedded organoids, start especially conservatively. Once retention and matrix integrity are stable, the method can be optimized for exchange fraction, throughput, and reproducibility.