Скачать или смотреть A Step-by-Step Protocol for Using Cell Strainers

Using a cell strainer correctly is key to maximizing cell recovery and ensuring sample quality. Here is a standard protocol, applicable to most cell suspension workflows.

Materials Needed
Cell strainer (appropriate mesh size: e.g., 70 µm for general use)

Sterile petri dish (e.g., 60 mm) or the strainer’s own collection tube

Sterile syringe plunger back (or the rubber end of a 1-5 mL syringe)

Complete culture medium or appropriate buffer (e.g., PBS with 2% FBS)

Sample: cell suspension (from culture or tissue digest)

Optional: Sterile forceps

Step-by-Step Procedure
1. Preparation & Pre-Wetting

Aseptically remove the strainer from its packaging. If using a reusable metal strainer, ensure it is properly sterilized (e.g., autoclaved).

Place the strainer over a sterile petri dish or a 15/50 mL conical tube.

Pre-wet the mesh: Pipette 1-2 mL of cold culture medium or buffer onto the mesh. This lubricates the pores, reduces nonspecific cell binding, and improves flow and recovery. Gently tilt to coat the entire mesh.

2. Sample Application

Slowly pour or pipette your cell suspension onto the center of the pre-wetted mesh. For larger volumes (more than 10 mL), pour in aliquots to avoid overflow.

Do not overload. If the sample is very dense or has large fragments, dilute it 1:1 with buffer before straining.

3. Gentle Filtration

Use the flat, sterile back of a syringe plunger to gently press and swirl the sample through the mesh. Apply minimal, even pressure.

Critical: Never use the tip of a pipette or a sharp instrument to grind cells, as this can damage the mesh and shear cells.

4. Rinse & Recovery

Once the initial sample has passed through, add 1-2 mL of fresh medium/buffer to the strainer to wash any remaining cells through. Gently swirl the plunger again.

For maximum recovery, you can carefully pipette buffer against the underside (bottom) of the mesh to dislodge cells caught in the pores.

5. Final Collection & Discard

Your filtered single-cell suspension is now in the collection dish or tube. Cap it and place it on ice if proceeding to downstream steps.

Discard the strainer appropriately (if disposable) or clean it immediately (if reusable). The mesh will retain unwanted clumps, tissue fragments, and debris.

Pro Tips for Success
Sequential Straining: For very complex samples (e.g., primary tissue), use two strainers: first a 100 µm to remove large fragments, then a 70 µm or 40 µm for a fine single-cell suspension.

Keep it Cold: Work quickly and keep samples/media cold (2-8°C) to maintain cell viability, especially for sensitive primary cells.

Clog Prevention: If flow stops due to clogging, do not force it. Transfer the remaining liquid on the mesh to a new, pre-wetted strainer.

Check Viability: After straining, always take a small aliquot to count cells and check viability (e.g., with Trypan Blue) before proceeding with expensive assays.

Summary
The core principles are: pre-wet, apply gently, press softly, and rinse thoroughly. This simple, 5-minute step is a powerful tool to ensure your experiments start with a high-quality, clump-free cell suspension, paving the way for reliable and reproducible results.