Brightfield counting uses transmitted light and identifies cells by size and morphology. Viability depends on Trypan Blue dye exclusion, where dead cells stain blue. Fluorescence counting instead uses fluorescent cell stains or reporters. This allows viable and non-viable populations, as well as specific subpopulations, to be distinguished by distinct fluorescent signals. Fluorescence is more sensitive for small or aggregated cells.
Instruments & Consumables
Automated Cell Counters and Viability Analysers
Logos Biosystems LUNA and QUANTOM automated cell counters for consistent, operator-independent counts
Counting cells by eye is slow, and it depends on who is doing the counting. The Logos Biosystems LUNA and QUANTOM Tx counters return concentration and viability data for your samples in seconds, with results that hold steady from operator to operator.
The range covers the LUNA family for mammalian cells, nuclei, and yeast and the QUANTOM Tx for microbial counting, with matched counting slides, calibration tools, stains, and accessories to keep your instrument running.
The LUNA-III and LUNA-BX7 handle your routine brightfield counting. The LUNA-FL and LUNA-FX7 add fluorescence channels for viability assessment using fluorescent dyes and GFP-positive counting in your transfection assays. The QUANTOM Tx counts individual bacterial cells that standard brightfield and fluorescence cell counters miss.
Each counter pairs with matched consumables: LUNA counting slides, QUANTOM counting slides, Trypan Blue and Erythrosin B stains, Acridine Orange / Propidium Iodide stain and QUANTOM viable and total cell staining kits. Calibration and validation tools support your regulated workflows, including IQ/OQ protocols and brightfield and fluorescence validation slides. The LUNA series holds the SelectScience Diamond Seal of Quality.
Choosing the counter by sample and readout
1) Routine mammalian counting. The LUNA-III suits your brightfield counts of healthy cell populations at low throughput. The LUNA-BX7 suits your higher throughput or strict quality control requirements. Both instruments cover most of your passaging and seeding decisions.
2) Viability and fluorescence. At low throughput, the LUNA-FL fits when you need live and dead discrimination in more challenging samples like PBMCs, or GFP-positive counting. For higher throughput or strict quality control requirements, the LUNA-FX7 fits, paired with fluorescence validation slides.
3) Microbial counting. The QUANTOM Tx resolves individual bacterial cells by fluorescence, where standard cell counters cannot. It pairs with the QUANTOM viable and total cell staining kits. The QUANTOM centrifuge brings bacterial cells into a single, correct focal plane for most accurate counting.
4) Viability stain. For brightfield viability, Trypan Blue or Erythrosin B fit your protocol. For viability assessment in fluorescent mode, AO/PI covers your assay. For total microbial staining, the QUANTOM Total Cell Staining Kit applies. For microbial viability, the QUANTOM viable cell staining kit applies.
5) Single cell experiments. For single cell work, including single cell sequencing, the LUNA-FX7 is the fit. Its fluorescence channels support the precise, high-quality counts your workflow demands.
6) Regulated environment. The IQ/OQ protocol and brightfield or fluorescence validation slides document your instrument's performance.
Applications
Cell culture maintenance and passaging
Counts before every passage keep your cell culture density consistent and prevent overgrowth, supporting reproducible passage timing.
Assay seeding uniformity
Accurate live-cell numbers ensure each well in your assay receives the same inoculum, reducing inter-well variability in viability, proliferation, and cytotoxicity readouts.
Bioprocess quality control
Cell density and viability at inoculation and during fed-batch runs feed directly into your process analytical technology workflows.
Microbial growth and susceptibility studies
The QUANTOM Tx resolves individual bacterial cells that standard cell counters miss, supporting your antibiotic susceptibility and growth-rate studies.
GFP reporter counting
Fluorescence channels count GFP-positive cells directly, so your fluorescent reporter readouts do not require a separate flow cytometer.
Single-cell workflow preparation
Precise, high-quality counts from the LUNA-FX7 support your single-cell experiments, including loading for single-cell sequencing platforms.
Product Catalog
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LUNA Automated Cell Counters
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Counting Slides
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Cell Counting Reagents & Viability Assays
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Calibration & Validation Tools
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QUANTOM Tx Microbial Cell Counter
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LUNA & QUANTOM Accessories
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Frequently asked questions
Trypan Blue exclusion is sufficient for healthy mammalian lines. Fluorescent stains work better when cells are small, or when brightfield contrast is low. Use them too when you need to count a labelled subpopulation.
Most automated counters work with 10 microlitres of cell suspension loaded onto a counting slide. Optimal density is typically 2x10^5 to 4x10^6 cells per millilitre. Outside this range, counts are less accurate. At low density, the statistical sample is small. At high density, cells overlap and are under-counted. Check the product page of your counter of interest to see the recommended density range.
Installation Qualification (IQ) and Operational Qualification (OQ) documents formally verify that an instrument is installed correctly and performs within specification. They are required for GMP-regulated manufacturing and clinical sample processing. They are also required in any environment where data integrity and audit trails must be demonstrated to a regulatory body.
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