1. Viability Measurement

2. Topic covered
Methods
Why
Definition

3. Definition The measure of proportion of alive and
metabolically active cell in a culture.
Cell viability measurement based on
various cell function :
Enzyme activity
Cell membrane permeability
Nucleotide uptake activity

4. Why viability measurement
is done ?
Cytotoxicity assays

5. MTT assay A colorimetric assay for the determination of
viable cell has been develop by using Tetrazolium
dye.
Measure of cellular oxidative metabolism or
detect mitochondrial dehydrogenase activites in
the living cell

6. Tetrazolim dye MTT ( yellow colour )
NADPH –dependent oxidoreductase enz.
Formazon ( purple colour )
It dissolve the insoluble formazon
Colored solution
O.D (500nm)
DMSO (Dimethyl sulfoxide) is added

8. LDH determination The damaged cell membrane allows the spillage
of Lactate dehydrogenase into the medium.
The loss of cell viability is followed by an increase
in enzyme activity of lactate dehydrogenase
in the culture medium.
They used as cell death marker ( eg adenylate
kinase and glucose-6-phosphate dehydrogenase)

10. Rate of protein or nucleic
acid synthesis
The intact cell growing in a culture media are
incubated with radioactivity labelled amino acids
or a nucleotide e.g Tritium –labelled thymidine
The rate of protein synthesis or nucleic acid
synthesis can be measured by estimating
radioactivity of the culture .

11. Trypan –blue dye Trypan blue dye stained Dead cells not live cell .
As the dye penetrate the membrane of non –viable
cell which are stained blue .

12. Colony forming Assay The culture were microscopically monitored for
colony formation.
Very less cell density is used.