The question asks to identify the technique NOT used for measuring cell viability in animal cell culture. Cell viability assays distinguish between living and dead cells, while cell counting methods simply enumerate the total number of cells.
Cell Viability Measurement Techniques
The following methods are commonly used to assess cell viability:
- Trypan blue dye exclusion: Live cells exclude the dye, while dead cells with damaged membranes take it up, appearing blue.
- Tetrazolium (MTT) assay: Measures the metabolic activity of viable cells, which reduce the tetrazolium salt to a colored product.
- LDH activity in the culture medium: Lactate dehydrogenase (LDH) is released from dead or damaged cells. Measuring its activity in the medium indicates cell death.
Cell Counting vs. Viability
A Coulter counter is an instrument that counts cells (and determines their volume) based on electrical impedance or light scattering. It measures the total number of cells present but does not differentiate between live and dead cells. Therefore, it is primarily a cell counting device, not a cell viability assay.
Thus, the Coulter counter is the correct answer as it is NOT used for the measurement of cell viability.
Important Questions from Kinetics of Cell Growth
- In the process of generating a clonal mammalian cell line, a single cell was seeded in a well of a cell culture plate. After the first 48 hours, one of the progeny cells underwent apoptosis due to a new mutation. If the doubling time of the cells is 24 hours and no more cell death occurs, the total number of cells after a total of 7 days from seeding will be ______. (answer in integer)
- A synchronous culture containing $1.8 \times 10^5$ monkey kidney cells was seeded into three identical flasks. The doubling time of these cells is 24 h. After 24 h, the cells from all the three flasks were pooled and dispensed equally into each well of three 6-well plates. The number of cells in each well will be ________ $\times 10^4$.
- Maximum specific growth rate ($\mu_{max}$) of a microorganism is calculated by taking the (In=loge, X=biomass, t = time)
- A T-flask is seeded with $10^5$ anchorage-dependent cells. The available area of the T-flask is $25 \text{ cm}^2$ and the volume of the medium is $25 \text{ ml}$. Assume that the cells are rectangles of size $5 \text{ µm} \times 2 \text{ µm}$. If the cells grow to monolayer confluence after $50 \text{ h}$, the growth rate in number of cells/($\text{cm}^2.\text{h}$) is _________ $ \times 10^5$.
- Determine the correctness or otherwise of the following Assertion (a) and the Reason (r) Assertion: In synchronous culture, majority of the cells move to next phase of the cell cycle simultaneously. Reason: Synchronous culture could be obtained by starving cells for essential nutrient components.
