Home
Back
Growth Rate Equation:
| From: | To: |
The cell culture growth rate (r) measures how rapidly cells are dividing in a culture. It's expressed as the natural logarithm of the ratio of final to initial cell counts divided by the time interval.
The calculator uses the growth rate equation:
Where:
Explanation: The equation calculates the exponential growth rate of cells in culture, which is useful for determining population doubling time and assessing culture health.
Details: Monitoring growth rate helps in experimental planning, assessing culture conditions, and determining optimal harvesting times. Abnormal rates may indicate contamination or suboptimal conditions.
Tips: Enter cell counts as whole numbers (use scientific notation for very large numbers). Time should be in hours (can use decimals for partial hours). All values must be positive.
Q1: What is a typical growth rate for mammalian cells?
A: Most mammalian cell lines have growth rates between 0.01-0.05 per hour, corresponding to doubling times of 14-70 hours.
Q2: How does this relate to doubling time?
A: Doubling time (td) can be calculated as \( \ln(2)/r \). A growth rate of 0.02 per hour corresponds to ~34.7 hour doubling time.
Q3: Should I use direct cell counts or optical density?
A: Direct counts (hemocytometer or automated counter) are most accurate. OD measurements require a standard curve for conversion to cell counts.
Q4: What affects growth rate accuracy?
A: Counting errors, non-exponential growth phases, and significant cell death can affect accuracy. Use mid-log phase measurements for best results.
Q5: Can this be used for bacterial cultures?
A: Yes, though bacterial growth rates are typically much higher (often >0.5 per hour), requiring shorter time intervals for accurate measurement.