Introduction to common cell dyes
Cell dyes are widely used in life science research for cell labeling, activity detection, organelle tracing, cell cycle analysis, etc. The following are the classification and details of common cell dyes:
Cell membrane dyes
It is used to label cell membranes to study cell morphology, migration, or cell-to-cell interactions.
1. DiI (DiIC18 (3))
Features: Lipophilic fluorescent dye (orange-red, Ex/Em Technologies 549/565 nm), stably embedded in cell membranes.
Applications: Cell tracking (e.g. nerve cell axon markers), cell fusion experiments.
2. DiO (DiOC18 (3))
Features: Green fluorescence (Ex/Em Technologies 484/501 nm), similar to DiI, suitable for multicolor marking.
3. PKH26/PKH67
Features: Long-acting membrane dye (PKH26: red; PKH67: green) for in vitro and in vivo cell tracking (e.g. stem cell migration).
4.FM series (such as FM1-43, FM4-64)
Characteristic: Dynamic membrane dye that marks endocytic or secretory activity (often used in synaptic vesicle studies).
Second, nuclear dyes
It is used to stain the nucleus and analyze the cell cycle, apoptosis or nuclear morphology.
1. DAPI (4 ', 6-diamidino-2-phenylindole)
Characteristics: Blue fluorescence (Ex/Em Technologies 358/461 nm), specific binding DNA (AT-enriched region).
Application: Fixed nuclear staining, co-labeling with fluorescent antibodies.
2. Hoechst 33342/33258
Features: Live cell penetrating nuclear dye (blue fluorescent), Hoechst 33342 is more commonly used for live cell imaging.
3. Propidium Iodide (PI)
Features: Red fluorescence (Ex/Em Technologies 535/617 nm), unable to penetrate live cell membranes, for staining dead cells or fixed nuclei.
4. SYTO/SYTOX series
- SYTO 9: green fluorescent, labeled with live cell nucleic acid.
- SYTOX Red: Red fluorescent, labeling only dead nuclei.
III. Cell reactive dyes
It is used to distinguish between living and dead cells or to detect cell health.
1. Trypan Blue
Features: Traditional dead cell dye (blue), taken by dead cells, rejected by living cells.
Application: Cell counter to detect survival rate.
2. Calcein-AM
- Features: Colorless and permeable membrane, green fluorescence after esterase hydrolysis in living cells (Ex/Em Technologies 494/517 nm).
Application: Live cell marker (often used in conjunction with PI).
3. FDA (Fluorescein Diacetate)
Features: Similar to Calcein-AM, green fluorescence, detection of cellular esterase activity.
4.7-AAD (7-Aminoactinomycin D)
Features: Red fluorescence for flow cytometry to distinguish between living and dead cells (detection of apoptosis in combination with Annexin V).
IV. Mitochondrial dyes
To study mitochondrial membrane potential, morphology or function.
1. JC-1
Features: Membrane potential-dependent dye (red aggregates formed at normal potential; green monomers upon depolarization).
Application: To detect mitochondrial function (e.g. early changes in apoptosis).
2. MitoTracker series
MitoTracker Red/Green: Long-acting dye (retained after fixation) for live-cell imaging.
- MitoSOX Red: Specific detection of mitochondrial superoxide (oxidative stress indicator).
3. Rhodamine 123
Features: Green fluorescent dye, membrane potential-dependent accumulation.
Fifth, lysosomal dyes
Label lysosomes or detect their acidic environment.
1. LysoTracker series
- LysoTracker Red/Green: acid-dependent fluorescence (Ex/Em Technologies 577/590 nm).
Applications: Autophagy studies, lysosomal localization.
2. Acridine Orange
Characteristics: Green (nuclear) and red (lysosome) dual fluorescence, pH sensitivity.
Endoplasmic reticulum (ER) and Golgi dyes
1.ER-Tracker (e.g. ER-Tracker Red/Green)
Features: Live cell-specific labeling of endoplasmic reticulum (requires low concentration use).
2. BODIPY TR Ceramide
- Features: labeled Golgi apparatus, red fluorescence.
Cell cycle dyes
For flow cytometry analysis of cell cycle (G1/S/G2-M phase).
1. PI (Propidium Iodide)
Requires RNase treatment: binds only DNA, distinguishes between periodic stages by fluorescence intensity.
2. DRAQ5/DRAQ7
Features: Far red fluorescence, good membrane permeability, suitable for live cell cycle analysis.
3.EdU/BrdU
- Features: Thymidine analogue, labeled proliferating cells (requires click chemistry or antibody detection).
Eight, calcium ion indicator
Detection of intracellular calcium signaling.
1. Fluo-3/Fluro-4
Features: Enhanced green fluorescence after calcium binding (Ex/Em Technologies 506/526 nm).
2. Fura-2
Features: Ratio dye (340/380 nm excitation), quantitative calcium concentration.
Nine, ROS (reactive oxygen species) detection dyes
1. DCFH-DA
Characteristics: Green fluorescence after oxidation by ROS (broad-spectrum ROS detection).
2. DHE (Dihydroethidine)
Characteristics: Superoxide specificity, red fluorescence after oxidation.
Select the appropriate dye according to the experimental requirements and optimize the dyeing conditions (concentration, time, temperature) to ensure specificity.
