⟡ Microbiology & Cell Analysis / Redox & Viability Assays
Cyanoditolyl Tetrazolium Chloride (CTC)
Cyanoditolyl tetrazolium chloride (CTC) is a redox-sensitive tetrazolium dye widely used to assess cellular metabolic activity and respiration. It is commonly applied in microbiology and cell biology workflows to identify actively respiring cells through the formation of a fluorescent formazan product.
CTC is frequently used for the direct epifluorescent enumeration of respiring bacteria in environmental, food, and marine samples. Upon reduction by components of the electron transport chain, CTC forms an insoluble, fluorescent formazan that accumulates within cells, allowing researchers to distinguish metabolically active populations using fluorescence microscopy.
Key Features & Benefits
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Redox indicator dye: measures cellular respiration and metabolic activity
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Direct detection of active cells: enables identification of respiring bacteria via intracellular formazan formation
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Fluorescent signal generation: reduced CTC forms a fluorescent formazan detectable by microscopy
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Rapid assay performance: measurable activity can be observed within minutes under appropriate conditions
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Supports quantitative workflows: used for enumeration of viable, metabolically active cells
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Applicable to diverse sample types: suitable for environmental, water, food, and microbiological samples
Typical Applications
Microbial viability and activity assessment
CTC is widely used to identify metabolically active bacteria by detecting respiratory activity at the single-cell level.
Environmental and water sample analysis
Used for epifluorescent microscopic enumeration of respiring bacteria in environmental and aquatic systems.
Marine microbiology studies
Applied in quantitative methodologies for measuring metabolic activity in marine bacterial populations.
Cellular redox activity assays
Utilized in studies evaluating electron transport chain activity and cellular respiration in both prokaryotic and eukaryotic systems.
Functional Role
CTC functions as a tetrazolium-based redox probe that is reduced by components of the cellular electron transport chain. This reduction produces an insoluble formazan precipitate that accumulates within actively respiring cells. The resulting fluorescent signal allows for direct visualization and quantification of metabolically active cells using fluorescence microscopy techniques.
Fluorescence Properties
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Formazan fluorescence: solid state
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Excitation maximum: 450 nm
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Emission maximum: 630 nm
Performance Notes
- CTC reduction is associated with active cellular respiration and electron transport activity.
- Signal intensity may vary depending on organism type, metabolic state, and assay conditions.
- Typical assays yield measurable activity within short incubation periods under appropriate conditions.
- CTC-based methods are commonly used for quantitative and comparative microbial activity studies.
Handling & Storage
- Store according to product specifications and label instructions.
- Protect from light to preserve dye integrity and fluorescence performance.
- Handle using appropriate laboratory safety practices.
- Refer to the Safety Data Sheet (SDS) for handling, storage, and safety information.
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FAQ
Click a question to expand.
What is Cyanoditolyl Tetrazolium Chloride (CTC) used for?
CTC is used to measure cellular respiration and metabolic activity by identifying actively respiring cells through formation of a fluorescent formazan product.
How does CTC detect active cells?
CTC is reduced by components of the electron transport chain in metabolically active cells, forming a fluorescent formazan that accumulates intracellularly and can be detected by microscopy.
What types of samples can be analyzed with CTC?
CTC is commonly used with environmental, water, marine, and food samples, as well as cultured microbial populations.
What microscopy methods are used with CTC?
CTC labeling is typically analyzed using epifluorescence microscopy and related fluorescence imaging techniques.
What are the fluorescence properties of CTC?
The reduced formazan product exhibits fluorescence with an excitation maximum near 450 nm and an emission maximum near 630 nm.
