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Thermo Scientific™ Invitrogen™ CountBright™ Plus Absolute Counting Beads for 100 Tests
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Bead diameter: ∼4 μm
Specifications:
| Application | Flow Cytometry | ||
| Storage Temperature | 2-8°C | ||
| Product Type | Flow Cytometry Reagents | Forms | Liquid |
| Product Brand | Thermo Fisher Scientific™, Invitrogen | ||
| Product Grade | Molecular Biology | ||
Invitrogen™ CountBright™ Plus Absolute Counting Beads are a ready-to-use suspension of highly fluorescent, ~4 µm polystyrene beads designed for absolute cell counting in flow cytometry. These beads offer a precise and reproducible method for quantifying the absolute number of cells per unit volume, especially when used on flow cytometers that do not have built-in volumetric capabilities.
The beads are excitable across a broad UV to IR wavelength range and exhibit bright fluorescence from 385–860 nm, making them compatible with virtually all modern flow cytometers. With >95% singlet content, CountBright Plus beads minimize aggregation, delivering improved counting accuracy and streamlined gating.
Key Features and Benefits
- Broad Laser Compatibility: Fluorescent across the UV to IR spectrum (385–860 nm)
- Accurate Quantification: Enables absolute cell counts without a volumetric flow cytometer
- Uniform Size (~4 µm): Matches the scale of most mammalian and blood cells for optimal comparison
- >95% Singlets: Reduces doublet formation for precise, reproducible analysis
- Convenient Format: Ready-to-use suspension for easy sample preparation and assay integration
- Flow Cytometry Optimized: Ideal for human whole blood, PBMCs, cultured cells, and more
Applications
- Absolute cell counting in research samples using flow cytometry
- Quantification of PBMCs, whole blood, and tissue-derived cells
- Standardization of cell concentration across experiments
- Cell enumeration in viability, proliferation, and cytotoxicity assays
- Bead-based controls for flow cytometry calibration and instrument standardization
Technical Specifications
| Property | Specification |
|---|---|
| Bead Diameter | ~4 µm |
| Fluorescence Emission | 385–860 nm |
| Excitation Compatibility | UV to IR lasers |
| Singlet Content | >95% |
| Product Type | Absolute counting bead |
| Bead Format | Fluorescent polystyrene microspheres |
| Concentration | Pre-calibrated (ready-to-use) |
| Quantity | 100 tests |
| Volume | 5 mL bead suspension in buffer |
| Storage Temperature | 2–8 °C |
| Shipping Condition | Room temperature |
| Unit Size | Each |
| Product Line | CountBright™ |
How It Works
- Mix CountBright Plus beads with your cell suspension at a known volume.
- Run the sample on a flow cytometer alongside your fluorescent cell population.
- Calculate the absolute cell count using the ratio of bead events to cell events and known bead concentration.
CountBright™ Plus Absolute Counting Beads provide a reliable, accurate, and easy-to-use solution for absolute cell quantification in flow cytometry. With broad excitation/emission capabilities and high singlet purity, these beads are essential for quantifying cell populations in research involving blood, tissue, cultured cells, and immunology assays, especially when using non-volumetric cytometers.