Preparation Protocol
- Volume of Cell Stock Needed 0 mL
- Volume of Diluent (Media) Needed 0 mL
- Total Final Volume 0 mL
- Dilution Factor 1 : 0
Volume Visualization
Quick Reference: Batch Volumes
| Target Volume | Stock Volume Needed | Diluent Volume Needed | Total Cells Used |
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Cell Suspension Dilution Calculator
Understanding Cell Dilution Calculations
In biological laboratories, preparing cell suspensions with precise concentrations is a fundamental task. Whether you are seeding plates for cell culture, preparing samples for flow cytometry, or setting up an assay, accuracy is crucial. This calculator helps researchers determine the exact volume of cell stock and diluent (usually growth media or PBS) required to achieve a target cell density.
The Math Behind the Calculator
The calculation relies on the standard dilution equation, often referred to as the C1V1 equation. This fundamental formula relates concentration and volume before and after the dilution process.
The formula is expressed as:
\(C_1 \times V_1 = C_2 \times V_2\)
Where:
- C1: The initial concentration (Current Stock Concentration).
- V1: The volume of stock solution needed (This is what we solve for).
- C2: The desired final concentration.
- V2: The desired final total volume.
To find the volume of the stock solution required (\(V_1\)), the formula is rearranged:
\(V_1 = \frac{C_2 \times V_2}{C_1}\)
Once \(V_1\) is known, the volume of the diluent is calculated by subtracting the stock volume from the total target volume:
\(Volume_{diluent} = V_2 - V_1\)
Accounting for Cell Viability
In many experimental scenarios, using the total cell count is insufficient because dead cells do not contribute to growth or assay results. It is standard practice to perform a Trypan Blue exclusion test to determine viability percentages before dilution.
If your stock is not 100% viable, you must adjust the initial concentration to reflect only the "effective" living cells. This calculator includes a viability correction feature. The modified formula used is:
\(V_1 = \frac{C_2 \times V_2}{C_1 \times (\frac{Viability\%}{100})}\)
This ensures that the final solution contains the desired concentration of live cells, preventing under-seeding of culture plates.
Common Applications
- Passaging Cells: Diluting a confluent flask into new vessels for continued growth.
- Drug Treatment Assays: Ensuring all wells in a 96-well plate have identical cell numbers before adding compounds.
- Transfection: Optimizing the cell-to-DNA ratio requires precise cell density.
- Cryopreservation: preparing cells at specific densities for freezing.
Tips for Accurate Dilutions
- Thorough Mixing: Always vortex or gently pipette your cell suspension before sampling for counting to ensure homogeneity.
- Hemocytometer Accuracy: When counting manual samples, count at least 100 cells across multiple squares to reduce statistical error.
- Pipetting Error: For very small volumes of stock (less than 5µL), consider making an intermediate dilution first to improve accuracy.