Flow Cytometry Hub | Comprehensive Resource Center

Flow Cytometry Instruments

A comprehensive directory of current flow cytometry instruments on the market, organized by manufacturer. Click any instrument name to visit the vendor product page.

Instrument Categories

🔬 Analyzers

Measure fluorescence and scatter but do not sort cells. Ideal for immunophenotyping, cell counting, and multicolor analysis. Generally lower cost and easier to operate.

⚖ Cell Sorters

Physically isolate specific populations using electrostatic deflection or microfluidic valves. Enable downstream culture, genomics, or functional assays. Require more training and biosafety considerations.

🌈 Spectral Analyzers

Capture the full emission spectrum instead of using bandpass filters. Enable more fluorochromes per panel and better unmixing of overlapping spectra. Represent the latest generation of cytometry.

📷 Imaging / Mass Cytometers

Imaging cytometers combine flow cytometry with microscopy. Mass cytometers (CyTOF) use metal-tagged antibodies and time-of-flight mass spectrometry for 40+ parameter analysis with zero spectral overlap.

BD Biosciences Beckman Coulter Cytek Thermo Fisher Sony Biotechnology Agilent Bio-Rad Miltenyi Biotec Standard BioTools Sartorius Sysmex Stratedigm Apogee Flow

BD Biosciences

Industry leader with 50+ years of flow cytometry expertise. Offers the broadest portfolio spanning clinical diagnostics, high-parameter research, and cell sorting.

Instrument	Type	Lasers	Max Parameters	Key Features
BD FACSDiscover S8	Spectral Analyzer	Up to 8	High-parameter	SpectralFX Technology + CellView Image Technology; sub-cellular resolution
BD FACSymphony A5 SE	Spectral Analyzer	Up to 5	High-parameter	Spectral flow cytometry; full visible spectrum; autofluorescence unmixing
BD FACSymphony A5	Analyzer	Up to 5	50 parameters	Ultimate high-parameter system; identifies rare cell types
BD FACSymphony A3	Analyzer	Up to 3	30 parameters	High-parameter exploration; 28 colors; deep phenotyping
BD FACSymphony A1	Analyzer	Up to 3	16 colors	Compact benchtop; entry-level high-parameter; optional small particle module
BD FACSLyric	Clinical Analyzer	Up to 6	12 colors	Clinical workhorse; IVD; automated QC; BD FACSuite software
BD FACSymphony S6	Sorter	Up to 6	60 parameters	High-parameter sorting; cutting-edge optics; 6-way sorting
BD FACSMelody	Sorter	Up to 3	9 colors	Personal benchtop 4-way sorter; easy to use; temperature control

Vendor website: bdbiosciences.com/instruments

Beckman Coulter Life Sciences

Pioneer in flow cytometry, now centered on the CytoFLEX platform with avalanche photodiode (APD) detectors for superior sensitivity in a compact design.

Instrument	Type	Lasers	Max Parameters	Key Features
CytoFLEX	Analyzer	Up to 3	13 colors	Compact benchtop; APD detectors; high sensitivity; entry-level
CytoFLEX S	Analyzer	Up to 4	13 colors	Expanded research capabilities; 4th laser option; CytExpert software
CytoFLEX LX	Analyzer	Up to 6	21 colors	High-parameter benchtop; 6-laser capability; reduced spectral overlap
CytoFLEX nano	Nanoparticle Analyzer	Specialized	6 FL + 5 SSC	Nanoparticle detection down to 40 nm; purpose-built for EVs and viruses
CytoFLEX mosaic	Spectral Module	Add-on	Up to 88 channels	Modular spectral detection for CytoFLEX LX/S; dual unmixing algorithms; nanoparticle (≥80 nm)
CytoFLEX SRT	Sorter	Up to 4	15 colors	Benchtop sorter; gentle microfluidic sorting; integrated biosafety
DxFLEX	Clinical Analyzer	Up to 3	13 colors	IVD clinical; FDA 510(k) cleared; APD detectors; simplified compensation

Vendor website: beckman.com/flow-cytometry

Cytek Biosciences

Leader in full-spectrum profiling (FSP) technology. Also markets Amnis imaging and Guava easyCyte product lines acquired from Luminex/DiaSorin in 2023.

Instrument	Type	Lasers	Max Parameters	Key Features
Aurora Evo	Spectral Analyzer	Up to 5	40+ colors	Newest flagship (2025); 2x faster throughput; built-in small particle detection; harmonized
Aurora	Spectral Analyzer	Up to 5	40+ colors	Flagship full-spectrum profiling; 64 detectors; SpectroFlo; 2,600+ publications
Northern Lights	Spectral Analyzer	1–3	24+ colors	Value spectral; expandable lasers; single optical config; CLC clinical version
Aurora CS	Spectral Sorter	Up to 5	40+ colors	Full-spectrum cell sorting; SpectroFlo software; gentle sorting
Muse Micro	Compact Analyzer	1	5 parameters	Affordable entry-level; 488 nm laser; pre-optimized assay kits; drug discovery award winner
Guava easyCyte	Analyzer	Up to 3	14 parameters	Microcapillary fluidics; absolute cell counting; walkaway 96-sample automation
Amnis ImageStream X Mk II	Imaging	Up to 5	12 channels	Imaging flow cytometry; 60x magnification; EV uptake imaging; IDEAS software

Vendor website: cytekbio.com

Thermo Fisher Scientific

Known for acoustic-focusing Attune platform and the high-end Bigfoot spectral sorter. Recently launched the Attune Xenith spectral analyzer.

Instrument	Type	Lasers	Max Parameters	Key Features
Attune Xenith	Spectral Analyzer	Up to 4	Spectral + conventional	Newest (2025); spectral unmixing + conventional modes; acoustic focusing; automation
Attune CytPix	Analyzer + Imaging	Up to 4	14 colors	Acoustic focusing + brightfield camera; AI image analysis; 6,000 images/sec
Attune NxT	Analyzer	Up to 4	16 parameters	Acoustic focusing workhorse; no-clog; high throughput; autosampler
Bigfoot Spectral Cell Sorter	Spectral Sorter	Up to 9	60 detectors	High-speed sorting (70K eps); 6-way; spectral + conventional; 1536-well plate sorting

Vendor website: thermofisher.com/flow-cytometers

Sony Biotechnology

Pioneer in spectral flow cytometry and microfluidic chip-based sorting with patented CoreFinder automation. Broadest sorter lineup on the market.

Instrument	Type	Lasers	Max Parameters	Key Features
ID7000 Spectral Cell Analyzer	Spectral Analyzer	Up to 7	44+ colors (186 detectors)	Highest detector count; 320–808 nm laser range; standardization mode; autosampler
SA3800 Spectral Cell Analyzer	Spectral Analyzer	Up to 4	34 data points (32-ch PMT)	Prism-based collection; automated startup/QC; global standardization; 384-well plates
SP6800 Spectral Cell Analyzer	Spectral Analyzer	3	16+ colors (66 data points)	Compact spectral; 32-ch PMT; FCS Express included; standardization mode
FP7000 Spectral Cell Sorter	Spectral Sorter	Up to 6	44+ colors (182 PMTs)	High-parameter spectral sorting; 6-way; 25K eps; CoreFinder; Class 1 laser
MA900 Multi-Application Cell Sorter	Sorter	4	14 parameters	Versatile 4-way sorter; chip-based; automated setup; multi-application flexibility
SH800S Cell Sorter	Sorter	Up to 4	8 parameters	Benchtop chip sorter; highest automation; CoreFinder; 2-way tube + plate sorting
FX500 Exchangeable Fluidics Cell Sorter	Sorter	Up to 3	6 FL parameters	Fully replaceable fluidics path; zero carryover; NSF49 biosafety; CoreFinder
CGX10 Cell Isolation System	GMP Cell Sorter	Closed system	Multi-marker	Fully closed GMP-compliant; cell therapy manufacturing; 100K eps enrichment; sterile consumables

Vendor website: sonybiotechnology.com/instruments

Agilent Technologies

NovoCyte platform known for ease-of-use, fixed optical alignment, and volumetric-based absolute cell counting without beads. Celebrating 10 years of the NovoCyte platform.

Instrument	Type	Lasers	Max Parameters	Key Features
NovoCyte Opteon	Spectral Analyzer	3–5	40+ markers (73 detectors)	Newest; spectral flow cytometry; flexible panel design; NovoExpress software
NovoCyte Penteon	Analyzer	5 (UV/V/B/Y/R)	30 FL channels	5-laser high-parameter; 30 independent detectors; high-end multicolor panels
NovoCyte Quanteon	Analyzer	4	25 FL channels	4-laser; 7.2 log dynamic range; proprietary PMT technology; demanding panels
NovoCyte Advanteon	Analyzer	1–3	Up to 17 parameters	Advanced mid-range; sophisticated multicolor assays; simple operation
NovoCyte	Analyzer	1–3	Up to 17 parameters	Budget-friendly entry; exchangeable filters; volumetric counting; NovoSampler

Vendor website: agilent.com/flow-cytometer-systems

Bio-Rad Laboratories

Offers the ZE5 Cell Analyzer platform with flexible laser configurations and Everest software. The S3e Cell Sorter has been discontinued but remains supported.

Instrument	Type	Lasers	Max Parameters	Key Features
ZE5 Cell Analyzer	Analyzer	3–5	Up to 30 parameters	Flexible configs (3–5 laser); Everest software; SPD option; 21 CFR Part 11; plate loader; 22-hr run time

Vendor website: bio-rad.com/flow-cytometers

Miltenyi Biotec

MACSQuant platform integrates flow cytometry with MACS magnetic cell separation, offering unique autolabeling and column integration capabilities.

Instrument	Type	Lasers	Max Parameters	Key Features
MACSQuant X	HTS Analyzer	3	16 channels	High-throughput screening; thousands of samples/day; maximum speed and reliability
MACSQuant Analyzer 16	Analyzer	3	16 parameters	Advanced immunophenotyping; compact; automated data acquisition
MACSQuant Analyzer 10	Analyzer	3	10 channels	Digital benchtop; robust fluidics; MACS column integration; GMP-ready
MACSQuant VYB	Analyzer	3	10 detectors (8 colors)	Violet-Yellow-Blue laser config; fluorescent protein detection; compact

Vendor website: miltenyibiotec.com/flow-cytometers

Standard BioTools (formerly Fluidigm)

Pioneered mass cytometry (CyTOF) technology using metal-tagged antibodies and time-of-flight mass spectrometry. Zero spectral overlap enables 50+ simultaneous markers.

Instrument	Type	Lasers	Max Parameters	Key Features
CyTOF XT PRO	Mass Cytometry	N/A (ICP-TOF-MS)	50+ metals	Newest (2025); 4x faster throughput; 21 CFR Part 11 compliance; clinical trial optimized
CyTOF XT	Mass Cytometry	N/A (ICP-TOF-MS)	50+ metals	4th-gen CyTOF; fully automated; 13-sample carousel; no compensation needed
Hyperion XTi Imaging System	Imaging Mass Cytometry	N/A (laser ablation)	40+ metals	Whole slide imaging; 40-slide autoloader; dual imaging/flow modes; tissue analysis

Vendor website: standardbio.com/instruments

Sartorius

Purpose-built iQue platform for high-throughput screening (HTS) by cytometry. Processes 96-well plates in 5 minutes using patented air-gap sampling.

Instrument	Type	Lasers	Max Parameters	Key Features
iQue 5	HTS Analyzer	3–4	25 colors (27 channels)	Newest (2025); improved fluidics; auto-clog detection; 96/384-well plates
iQue 3	HTS Analyzer	Up to 3	Multiple configs	Fastest sample acquisition; 96/384/1536-well plates; robotics integration; Forecyt software

Vendor website: sartorius.com/flow-cytometry

Sysmex

Clinical diagnostics leader combining flow cytometry with automated sample preparation. Also offers compact CyFlow analyzers for research and industrial applications.

Instrument	Type	Lasers	Max Parameters	Key Features
XF-1600	Clinical Analyzer	Multiple	10 colors	Clinical IVD; pairs with PS-10 for full walkaway automation; XN-Series fluidics heritage
PS-10 Sample Preparation System	Sample Prep	N/A	N/A	Automated antibody staining, incubation, and transfer to XF-1600; barcoded rotors
CyFlow Cube 6 V2m	Compact Analyzer	Up to 2	6 parameters	Ultra-compact desktop; research and industrial applications; DNA ploidy analysis
CyFlow Ploidy Analyzer	Specialized Analyzer	1	DNA content	Dedicated plant/animal ploidy; agriculture; aquaculture; compact

Vendor website: sysmex.com/flow-cytometry

Stratedigm

Silicon Valley manufacturer of customizable, upgradeable benchtop flow cytometers. Anti-Obsolescence Guarantee ensures long instrument lifecycle.

Instrument	Type	Lasers	Max Parameters	Key Features
S1000EON Spectra	Spectral + Conventional	Up to 6	30 parameters	Newest; dual spectral + conventional modes; scalable; Flowraissance upgrade path
S1000EON	Analyzer	Up to 6	30 parameters	5-decade dynamic range; microparticle mode (0.2–7 µm); laser-trimming technology
S1200Ex	Analyzer	3	12 colors	Complete analysis system; CellCapTure software; A600 plate loader compatible

Vendor website: stratedigm.com

Apogee Flow Systems

British manufacturer specializing in nano flow cytometry for small particles. Reference system for extracellular vesicle, virus, and nanoparticle analysis worldwide.

Instrument	Type	Lasers	Max Parameters	Key Features
A60 Micro-PLUS	Nanoparticle Analyzer	Up to 3	3 FSC + 9 FL	Resolves 100 nm silica beads by scatter; reference for EV/virus studies; triple FSC
A50 Micro	Nanoparticle Analyzer	Up to 3	Multiple FL	EV analysis in liquid biopsies; sensitive standard tool; custom configurations
Kairos cLDEP Sorter	Nanoparticle Sorter	Module add-on	N/A	First cLDEP particle sorter; electric field sorting; no moving parts; 10x faster than piezo; biohazard safe

Vendor website: apogeeflow.com

Flow Cytometry Reagents

Comprehensive reference for fluorochromes, dyes, and staining reagents used in flow cytometry applications.

🌈 Comprehensive Fluorophore Selection Guide 📊 Interactive Spectrum Viewer Tool

Common Fluorochromes by Laser Line

Fluorochrome	Excitation (nm)	Emission (nm)	Laser	Brightness	Common Use
FITC	488	520	Blue (488)	Medium	General immunophenotyping; widely available conjugates
PE (R-Phycoerythrin)	488/565	575	Blue/Yellow-Green	Very Bright	Low-expression markers; excellent signal-to-noise
PerCP	488	678	Blue (488)	Medium	CD4/CD8 panels; no tandem instability
PerCP-Cy5.5	488	695	Blue (488)	Medium	Multicolor panels; extended red emission
APC (Allophycocyanin)	633/640	660	Red (633)	Bright	Low-expression markers; minimal autofluorescence channel
APC-Cy7	633/640	785	Red (633)	Bright	High-parameter panels; far-red detection
Alexa Fluor 488	488	519	Blue (488)	Bright	FITC alternative; more photostable
Alexa Fluor 647	633	668	Red (633)	Bright	APC alternative; excellent photostability
Alexa Fluor 700	633	723	Red (633)	Medium	Red laser panels; minimal PE spillover
Pacific Blue	405	455	Violet (405)	Medium	Violet laser panels; dump channel markers
BV421 (Brilliant Violet 421)	405	421	Violet (405)	Very Bright	Low-expression markers on violet laser
BV510	405	510	Violet (405)	Bright	Viability or dump channel; green emission off violet
BV605	405	605	Violet (405)	Very Bright	High-parameter panels; excellent resolution
BV711	405	711	Violet (405)	Bright	Deep phenotyping panels
BV786	405	786	Violet (405)	Bright	Far-red off violet laser; high-parameter panels
BUV395	355	395	UV (355)	Bright	UV laser panels; minimal spectral overlap
BUV737	355	737	UV (355)	Bright	Extended UV panels; BD-exclusive
PE-Cy5	488/565	667	Blue/Yellow-Green	Bright	Legacy panels; tandem dye
PE-Cy7	488/565	785	Blue/Yellow-Green	Very Bright	High-expression markers; far-red from blue laser
Cy5	633	670	Red (633)	Medium	Nucleic acid labeling; general research

Viability Dyes

Dye	Type	Excitation	Emission	Fixable?	Notes
Propidium Iodide (PI)	Membrane-impermeant	535	617	No	Classic dead-cell exclusion; intercalates DNA; not compatible with fixation
7-AAD	Membrane-impermeant	488	647	No	Less spectral overlap with FITC/PE than PI; rapid staining
DAPI	Membrane-impermeant	360	460	No	Requires UV or violet laser; AT-base pair selective
SYTOX Blue	Membrane-impermeant	444	480	No	High-affinity nucleic acid stain; low background
SYTOX Green	Membrane-impermeant	488	523	No	Bright; simple protocol; use at low concentration
LIVE/DEAD Fixable Violet	Amine-reactive	405	452	Yes	Reacts with free amines; dead cells stain brighter after fixation
LIVE/DEAD Fixable Aqua	Amine-reactive	405	526	Yes	Popular fixable dye; violet laser; good for intracellular staining protocols
LIVE/DEAD Fixable Near-IR	Amine-reactive	633	750	Yes	Red laser excitation; minimal panel interference
Zombie Aqua	Amine-reactive	405	516	Yes	BioLegend fixable dye; excellent discrimination; cost-effective
Zombie NIR	Amine-reactive	633	746	Yes	Near-infrared; minimal panel conflict; fixable
eFluor 780	Amine-reactive	633	780	Yes	Thermo Fisher fixable viability; APC-Cy7 channel
Calcein AM	Enzymatic (live-cell)	488	515	No	Only live cells convert to fluorescent calcein; measures esterase activity

DNA & Cell Cycle Dyes

Dye	Excitation	Emission	Mechanism	Cell Cycle Use	Notes
Propidium Iodide	535	617	DNA intercalator	Yes (fixed cells)	Requires RNase treatment; stoichiometric binding to dsDNA
DAPI	360	460	Minor groove binder	Yes	AT-preferring; requires UV/violet laser; compatible with many fluorochromes
Hoechst 33342	350	461	Minor groove binder	Yes (live cells)	Cell-permeable; used for side population sorting; UV laser required
Hoechst 33258	352	461	Minor groove binder	Yes	Similar to 33342 but less cell-permeable; often used with fixed cells
DRAQ5	633	681	DNA intercalator	Yes (live cells)	Cell-permeable; red laser; far-red emission; no RNase needed
DRAQ7	633	681	DNA intercalator	Viability only	Cell-impermeant version of DRAQ5; dead-cell discriminator
FxCycle Violet	405	440	DNA binding	Yes	Violet laser; no RNase needed; Thermo Fisher product
SYTOX Green	488	523	Nucleic acid stain	Limited	Primarily viability; can show DNA content in permeabilized cells
BrdU / EdU	Various	Various	Thymidine analog incorporation	S-phase specific	Requires antibody (BrdU) or click chemistry (EdU) detection
Ki-67 antibody	Various	Various	Protein marker	Proliferation marker	Absent in G0; present in G1, S, G2, M; requires fixation/permeabilization

Functional Probes & Indicators

Probe	Function Measured	Excitation	Emission	Notes
CFSE / CellTrace Violet	Cell proliferation (division tracking)	488 / 405	521 / 450	Diluted by half with each division; track up to 8 generations
Fluo-4 AM	Intracellular calcium	488	516	Increases fluorescence with Ca²⁺ binding; real-time kinetics
Indo-1	Intracellular calcium (ratiometric)	355	405/485	UV excitation; ratio of bound/free forms; requires UV laser
JC-1	Mitochondrial membrane potential	488	530/590	Green monomer (depolarized) vs red aggregate (polarized); ratiometric
MitoTracker Red	Mitochondrial mass/potential	488/579	599	Fixable; accumulates in active mitochondria
TMRE / TMRM	Mitochondrial membrane potential	488	575	Non-ratiometric; lost upon depolarization; use at low [nM] range
CM-H2DCFDA (DCF)	Reactive oxygen species (ROS)	488	529	Oxidized by ROS to fluorescent DCF; broad ROS detection
MitoSOX Red	Mitochondrial superoxide	488/510	580	Selective for mitochondrial superoxide; oxidized product binds DNA
Annexin V conjugates	Early apoptosis (PS exposure)	Various	Various	Binds phosphatidylserine; requires Ca²⁺; combine with viability dye
FLICA (FAM-VAD-FMK)	Active caspases	488	530	Cell-permeable; binds active caspases irreversibly; fixable
DiOC6	Mitochondrial membrane potential	488	501	Green fluorescence; lost upon depolarization
LysoTracker Red	Lysosomal content	488/577	590	Acidotropic probe; accumulates in acidic organelles

Tandem Dyes & Polymer Dyes

Tandem dyes use fluorescence resonance energy transfer (FRET) from a donor fluorochrome to an acceptor, enabling detection of multiple markers from a single laser. Polymer dyes (Brilliant Violet, Brilliant UV, Super Bright) are synthetic polymers with tunable emission spectra.

Dye	Type	Excitation	Emission	Notes
PE-Cy5	Tandem	488	667	PE donor → Cy5 acceptor; sensitive to degradation
PE-Cy7	Tandem	488	785	Very bright; PE donor → Cy7 acceptor; light/heat sensitive
APC-Cy7	Tandem	633	785	APC donor → Cy7 acceptor; avoid prolonged light exposure
APC-R700	Tandem	633	719	BD-specific; more photostable than APC-Cy7
PerCP-Cy5.5	Tandem	488	695	PerCP donor → Cy5.5 acceptor; relatively photostable
PE-CF594	Tandem	488	594	BD Horizon dye; better stability than PE-Texas Red
BV421	Polymer	405	421	Brilliant Violet series; exceptionally bright
BV510	Polymer	405	510	Good viability/dump channel dye off violet laser
BV605	Polymer	405	605	One of the brightest BV dyes; ideal for low-expression markers
BV711	Polymer	405	711	Far-red off violet; high-parameter panels
BV786	Polymer	405	786	NIR off violet; can replace APC-Cy7 in some panels
BUV395	Polymer	355	395	BD Horizon UV; requires UV laser
BUV496	Polymer	355	496	UV laser; good spread with BUV395
BUV661	Polymer	355	661	UV excitation; red emission; high-dimensional panels
BUV737	Polymer	355	737	Far-red from UV; minimal cross-laser spillover
BUV805	Polymer	355	805	NIR from UV; expanding panel capacity
Super Bright 436	Polymer	405	436	Thermo Fisher polymer dye; violet laser
Super Bright 600	Polymer	405	600	Bright; similar channel to BV605

Important: When using multiple polymer dyes (BV, BUV, Super Bright) in the same panel, use a Brilliant Stain Buffer to prevent dye-to-dye interactions that cause aberrant staining.

Common Flow Cytometry Protocols

Step-by-step guides for the 20 most commonly used flow cytometry protocols. Click any protocol to expand the full procedure.

1. Viability Staining (PI / 7-AAD) ▼

Purpose

Discriminate live from dead cells using membrane-impermeant DNA dyes that only enter cells with compromised membranes.

Materials

Propidium Iodide (PI, 1 mg/mL stock) or 7-AAD (0.1 mg/mL)
FACS buffer (PBS + 2% FBS + 0.1% sodium azide)

Procedure

Harvest cells and wash 1x in FACS buffer.
Resuspend at 1 × 10⁶ cells/mL in FACS buffer.
Complete surface staining if needed (add antibodies, incubate 20 min at 4°C, wash).
Add PI to a final concentration of 0.5–1 µg/mL (or 7-AAD at 5 µL per test).
Incubate 5–10 minutes at room temperature in the dark.
Do not wash after adding viability dye.
Acquire on cytometer within 30 minutes.

Tip: PI and 7-AAD are not compatible with fixation. For fixed samples, use a fixable amine-reactive viability dye (see Protocol 20).

2. Surface Antibody Staining ▼

Purpose

Label cell surface antigens with fluorochrome-conjugated antibodies for immunophenotyping.

Materials

Fluorochrome-conjugated antibodies (titrated to optimal concentration)
FACS buffer, Fc block (anti-CD16/CD32 or Human TruStain FcX)

Procedure

Prepare single-cell suspension; count and assess viability.
Aliquot 0.5–1 × 10⁶ cells per tube/well.
Add Fc block (if applicable) and incubate 10 min at 4°C.
Add pre-titrated antibody cocktail.
Incubate 20–30 minutes at 4°C in the dark.
Wash 2x with 2 mL FACS buffer, centrifuge at 400 × g, 5 min.
Resuspend in 200–300 µL FACS buffer.
Add viability dye if desired. Acquire on cytometer.

Tip: Always titrate antibodies to find the optimal concentration. More antibody is not always better — excess can increase background.

3. Cell Cycle Analysis (PI/RNase) ▼

Purpose

Quantify DNA content to determine cell cycle distribution (G0/G1, S, G2/M phases).

Materials

70% ethanol (ice-cold)
PI staining solution: 50 µg/mL PI + 100 µg/mL RNase A in PBS

Procedure

Harvest cells (minimum 0.5 × 10⁶), wash 1x in PBS.
Fix by adding ice-cold 70% ethanol dropwise while vortexing gently.
Incubate at −20°C for at least 2 hours (or overnight).
Wash 2x in PBS to remove ethanol.
Resuspend in 0.5 mL PI/RNase staining solution.
Incubate 30 minutes at 37°C in the dark.
Acquire at low flow rate (collect ≥10,000 events on singlet gate).
Use doublet discrimination (FSC-H vs FSC-A) to exclude aggregates.

Caution: Doublet discrimination is essential. Cell clumps will appear as G2/M events and skew results. Use pulse geometry gating (FSC-H vs FSC-W or FSC-H vs FSC-A).

4. Apoptosis Detection (Annexin V / PI) ▼

Purpose

Distinguish early apoptotic (Annexin V+/PI−), late apoptotic/necrotic (Annexin V+/PI+), and viable (Annexin V−/PI−) cells.

Materials

Annexin V conjugate (FITC, PE, or APC)
Propidium Iodide (PI) or 7-AAD
Annexin V Binding Buffer (10 mM HEPES, 140 mM NaCl, 2.5 mM CaCl₂, pH 7.4)

Procedure

Harvest cells and wash 1x in cold PBS.
Wash 1x in Annexin V Binding Buffer.
Resuspend 1 × 10⁵–10⁶ cells in 100 µL Binding Buffer.
Add 5 µL Annexin V conjugate and 5 µL PI (or 7-AAD).
Incubate 15 minutes at RT in the dark.
Add 400 µL Binding Buffer. Do not wash.
Acquire within 1 hour (PI/7-AAD signal degrades over time).

Caution: Calcium is essential for Annexin V binding. Always use Annexin V Binding Buffer — never PBS or FACS buffer for this assay.

5. Intracellular Cytokine Staining (ICS) ▼

Purpose

Detect cytokine production (IFN-γ, TNF-α, IL-2, IL-4, IL-17, etc.) by individual cells after stimulation.

Materials

Stimulation agents: PMA (50 ng/mL) + ionomycin (1 µg/mL) or antigen-specific peptides
Protein transport inhibitor: Brefeldin A (GolgiPlug, 1 µL/mL) or Monensin (GolgiStop)
Fixation/Perm kit (BD Cytofix/Cytoperm or equivalent)
Surface and intracellular antibodies

Procedure

Stimulate cells with PMA/ionomycin (or antigen) for 4–6 hours at 37°C.
Add Brefeldin A or Monensin after the first hour of stimulation (or at time 0).
After stimulation, wash cells and perform surface staining (20 min, 4°C).
Wash and add fixable viability dye (see Protocol 20).
Fix cells: add 250 µL Cytofix/Cytoperm, incubate 20 min at 4°C.
Wash 2x with 1x Perm/Wash buffer.
Add intracellular antibodies in Perm/Wash buffer, incubate 30 min at 4°C.
Wash 2x with Perm/Wash buffer, resuspend in FACS buffer.
Acquire. Include unstimulated control and FMO controls.

Tip: Always include an unstimulated control to set the cytokine-positive gate. FMO controls are superior to isotype controls for defining positive populations.

6. Phospho-Flow (Intracellular Phosphoprotein) ▼

Purpose

Measure phosphorylation of intracellular signaling proteins (pSTAT1, pSTAT3, pSTAT5, pERK, pS6, pAKT) at single-cell resolution.

Materials

BD Phosflow Fix Buffer I (or 1.5% PFA) and Perm Buffer III (or 90% methanol)
Phospho-specific antibodies (BD Phosflow or Cell Signaling Technology)

Procedure

Stimulate cells with cytokine/growth factor at 37°C for optimal time (1–30 min depending on target).
Immediately fix: add pre-warmed Fix Buffer I (or 1.5% PFA), vortex, incubate 10 min at 37°C.
Chill on ice 1 min. Centrifuge 600 × g, 5 min.
Permeabilize: resuspend in ice-cold Perm Buffer III (or 90% methanol), vortex, incubate 30 min on ice.
Wash 2x in FACS buffer (staining buffer).
Stain with phospho-specific antibodies and surface markers (30–60 min at RT).
Wash 2x, resuspend in FACS buffer. Acquire.

Caution: Methanol permeabilization destroys many surface epitopes and fluorescent proteins (e.g., GFP). Test antibody compatibility with the fixation/permeabilization method beforehand.

7. CFSE / CellTrace Proliferation Tracking ▼

Purpose

Track cell division by labeling cells with a fluorescent dye that is halved with each division, creating distinct peaks for each generation.

Materials

CFSE (5 mM stock in DMSO) or CellTrace Violet (5 mM stock)
Warm complete medium, PBS

Procedure

Wash cells 2x in PBS (remove serum — proteins quench CFSE labeling).
Resuspend at 1–10 × 10⁶/mL in PBS.
Add CFSE to 2–5 µM final (or CellTrace Violet to 2.5–5 µM).
Incubate 10–20 min at 37°C in the dark.
Quench by adding 5 volumes warm complete medium. Incubate 5 min.
Wash 2x in complete medium.
Culture cells with stimulation for 3–7 days.
Harvest, perform surface staining, add viability dye, and acquire.
Analyze proliferation peaks using FlowJo Proliferation modeling.

Tip: Include a Day 0 sample (labeled but not stimulated) to set the undivided peak position. CellTrace Violet has better resolution than CFSE for many applications.

8. Regulatory T Cell (Treg) Staining ▼

Purpose

Identify regulatory T cells (CD4+CD25+FoxP3+ or CD4+CD25+CD127low) in blood or tissue samples.

Materials

Surface antibodies: anti-CD3, anti-CD4, anti-CD25, anti-CD127
Intracellular: anti-FoxP3, anti-CTLA-4, anti-Helios (optional)
FoxP3/Transcription Factor Staining Buffer Set (eBioscience or equivalent)

Procedure

Perform surface staining for CD3, CD4, CD25, CD127 (20 min, 4°C).
Add fixable viability dye, incubate 15 min.
Wash cells. Fix and permeabilize using FoxP3 Fix/Perm buffer (30 min–overnight, 4°C).
Wash 2x in 1x Permeabilization Buffer.
Add anti-FoxP3 (and other intranuclear markers) in Perm Buffer. Incubate 30–45 min at RT.
Wash 2x in Perm Buffer, resuspend in FACS buffer. Acquire.

Tip: The FoxP3 staining kit requires a specific fixation/permeabilization buffer that differs from the Cytofix/Cytoperm used for cytokines. Do not interchange these kits.

9. FoxP3 / Transcription Factor Nuclear Staining ▼

Purpose

Detect nuclear transcription factors (FoxP3, T-bet, GATA-3, RORγt, Bcl-6, Eomes, Ki-67) requiring nuclear permeabilization.

Materials

eBioscience FoxP3/Transcription Factor Staining Buffer Set (cat# 00-5523-00) or Tonbo kit
Transcription factor antibodies

Procedure

Complete all surface staining and viability staining first.
Wash cells. Add 1 mL Fix/Perm working solution. Vortex immediately.
Incubate 30 min to overnight at 4°C in the dark.
Wash 2x with 1x Permeabilization Buffer (centrifuge 400–600 × g, 5 min).
Add intranuclear antibodies diluted in 1x Permeabilization Buffer.
Incubate 30 min at RT in the dark.
Wash 2x with 1x Permeabilization Buffer.
Resuspend in FACS buffer. Acquire or store at 4°C protected from light (up to 24 h).

Caution: Many surface markers are destroyed by the nuclear perm buffer. Always stain surface markers before fixation/permeabilization. Test each antibody clone for compatibility.

10. Compensation Bead Controls ▼

Purpose

Generate single-stained controls for accurate compensation (spectral overlap correction) using antibody-capture beads.

Materials

Compensation beads (e.g., BD CompBeads, UltraComp eBeads, OneComp eBeads, or ArC Amine Reactive beads for viability dyes)
One antibody conjugate per tube (same clone/fluorochrome as in the panel)

Procedure

Add one drop (~50 µL) of positive and negative beads to each tube.
Add the recommended volume of each single antibody to its respective tube.
Incubate 15–20 min at RT in the dark.
Add 2 mL FACS buffer. Centrifuge 300 × g, 5 min. Decant.
Resuspend in 300 µL FACS buffer.
For viability dyes: use ArC beads (amine-reactive) or dedicate a cell aliquot.
Acquire each comp tube on the cytometer using the same voltages as the experiment.
Calculate compensation matrix in software (FACSDiva, SpectroFlo, FlowJo).

Tip: Comp beads must be at least as bright as the cells. If a bead is dimmer than the stained cell population, use stained cells as the comp control for that channel.

11. Reactive Oxygen Species (ROS) Detection ▼

Purpose

Measure intracellular ROS production using oxidation-sensitive fluorescent probes.

Materials

CM-H2DCFDA (General Oxidative Stress Indicator, 10 mM stock in DMSO)
MitoSOX Red (for mitochondrial superoxide, 5 mM stock in DMSO)
Positive control: H₂O₂ (100–500 µM) or menadione

Procedure

Wash cells 1x in warm PBS (no phenol red, no serum).
Load with CM-H2DCFDA (2–10 µM) or MitoSOX Red (5 µM) in warm PBS.
Incubate 20–30 min at 37°C in the dark.
Wash 1x in warm complete medium or PBS + 2% FBS.
Optionally treat with stimuli/inhibitors for desired time.
Add viability dye (e.g., SYTOX Blue or DAPI). Acquire immediately.

Caution: DCF-based probes are irreversible indicators and can be oxidized by many cellular processes besides ROS. Include antioxidant controls (NAC, catalase) to confirm ROS specificity.

12. Mitochondrial Membrane Potential (JC-1 / TMRE) ▼

Purpose

Assess mitochondrial membrane potential (Δψm) as an indicator of mitochondrial health, early apoptosis, or metabolic state.

Materials

JC-1 (200 µM stock in DMSO) or TMRE (10 mM stock in DMSO)
CCCP or FCCP (50 mM stock) as depolarization positive control

Procedure (JC-1)

Prepare CCCP-treated positive control: pre-incubate cells with 50 µM CCCP for 5 min at 37°C.
Add JC-1 to all samples at 2 µM final concentration.
Incubate 20–30 min at 37°C, 5% CO₂, in the dark.
Wash 2x in warm PBS.
Resuspend in 300 µL PBS. Acquire immediately.
Measure green fluorescence (FL1, ~530 nm, monomers) and red fluorescence (FL2, ~590 nm, aggregates).
Calculate red/green ratio: higher ratio = healthy Δψm, lower ratio = depolarized.

Tip: TMRE is used at much lower concentrations (10–50 nM) in non-quench mode. Loss of signal indicates depolarization. TMRE is simpler to analyze than JC-1.

13. Calcium Flux Measurement ▼

Purpose

Measure real-time intracellular calcium mobilization in response to receptor stimulation using ratiometric or single-wavelength calcium indicators.

Materials

Indo-1 AM (ratiometric, requires UV laser) or Fluo-4 AM (single-wavelength, 488 nm)
Pluronic F-127 (to aid dye loading); stimulant (anti-CD3, thapsigargin, ionomycin)

Procedure

Resuspend cells at 5 × 10⁶/mL in warm RPMI + 2% FBS.
Add Indo-1 AM (1–5 µM) or Fluo-4 AM (1–2 µM) with 0.02% Pluronic F-127.
Incubate 30 min at 37°C in the dark with periodic mixing.
Wash 2x in warm RPMI + 2% FBS.
Allow dye de-esterification: incubate 30 min at 37°C in media.
Perform surface staining if needed (keep at 37°C).
Begin acquisition and record baseline (30–60 sec).
Add stimulant (without stopping acquisition) and record for 3–5 min.
Add ionomycin (1 µg/mL) as positive control to verify dye loading.

Tip: Indo-1 provides ratiometric measurement (bound/free) which is independent of dye concentration and cell size. Fluo-4 is easier to set up but is non-ratiometric.

14. Cell Sorting Sample Preparation ▼

Purpose

Prepare samples optimally for FACS sorting to maximize yield, viability, and purity of sorted populations.

Materials

Sort buffer: PBS + 1–2% FBS + 1 mM EDTA (sterile, filtered)
Cell strainer (40–70 µm), DNase I (optional)
Collection tubes with media (for viability)

Procedure

Prepare single-cell suspension (aim for ≥10 × 10⁶ cells for rare populations).
If clumping is present, add DNase I (10–100 µg/mL) during processing.
Filter through 40 µm cell strainer immediately before staining.
Perform surface antibody staining at optimal titrated concentrations.
Add viability dye (DAPI or SYTOX Blue preferred for sorting — no fixation needed).
Wash and resuspend in sort buffer at 10–20 × 10⁶/mL.
Filter again through 40 µm strainer into a sort tube (cap with strainer).
Keep cells on ice. Prepare collection tubes: add 0.5–1 mL FBS or complete medium.
Sort. Post-sort, re-analyze a small aliquot to verify purity (>95%).

Tip: EDTA in the sort buffer prevents cell clumping. Avoid sodium azide in sort buffer if cells will be cultured after sorting. Keep everything sterile for downstream culture.

15. Bacterial Viability Assessment ▼

Purpose

Determine bacterial viability and quantify live vs. dead bacteria in a sample using nucleic acid dyes.

Materials

SYTO 9 (cell-permeant green, labels all bacteria)
Propidium Iodide (labels membrane-compromised bacteria, displaces SYTO 9)
LIVE/DEAD BacLight kit (Thermo Fisher L7012) or equivalent

Procedure

Harvest bacteria at mid-log phase. Wash 1x in 0.85% NaCl or PBS.
Adjust to ~10⁶–10⁷ bacteria/mL.
Add SYTO 9 (5 µM) and PI (30 µM) from BacLight kit.
Incubate 15 min at RT in the dark.
Acquire at low flow rate (bacteria are small — adjust FSC threshold).
Gate on bacteria using FSC/SSC (may need log scale on both axes).
Live bacteria: SYTO 9-bright, PI-dim. Dead: PI-bright, SYTO 9-dim.

Tip: Lower the FSC threshold significantly for bacteria (they are 10–100x smaller than mammalian cells). Use counting beads for absolute quantification.

16. DNA Ploidy Analysis (Clinical) ▼

Purpose

Determine DNA ploidy (diploid vs. aneuploid) and calculate DNA index in tumor samples for prognostic assessment.

Materials

DAPI (4 µg/mL in staining buffer) or PI/RNase solution
Normal diploid reference cells (chicken/trout erythrocytes or normal lymphocytes)
Detergent-based nuclear isolation buffer (for FFPE: pepsin digestion buffer)

Procedure

For fresh tissue: mince, disaggregate, and filter to single nuclei/cells.
For FFPE tissue: deparaffinize, rehydrate, pepsin digest (0.5% pepsin in 0.9% NaCl, pH 1.5, 30 min, 37°C).
Filter through 50 µm mesh. Wash nuclei in PBS.
Add internal diploid reference standard.
Stain with DAPI or PI/RNase (same as cell cycle protocol).
Acquire ≥20,000 nuclei at low flow rate.
Calculate DNA Index = (G0/G1 peak channel of tumor) / (G0/G1 peak channel of reference).
DI = 1.0 is diploid; DI ≠ 1.0 is aneuploid.

17. BrdU / EdU Incorporation Assay ▼

Purpose

Identify cells actively synthesizing DNA (S-phase) by incorporation of the thymidine analog BrdU or EdU, providing more specific proliferation data than Ki-67 alone.

Materials

BrdU (10 mM stock) or EdU (10 mM stock, Click-iT kit)
For BrdU: anti-BrdU antibody (FITC or APC), DNase I, Fix/Perm buffers
For EdU: Click-iT reaction cocktail (azide-fluorochrome, CuSO4, ascorbic acid)

Procedure (BrdU)

Pulse cells with 10 µM BrdU for 1–4 hours at 37°C.
Harvest cells. Perform surface staining.
Fix with BD Cytofix/Cytoperm (30 min, 4°C). Wash in Perm/Wash.
Re-fix in Cytofix/Cytoperm Plus (10 min, 4°C). Wash.
Re-fix in Cytofix/Cytoperm (5 min, 4°C). Wash.
Treat with DNase I (300 µg/mL in DPBS) for 1 h at 37°C to expose BrdU epitopes.
Wash. Add anti-BrdU antibody (20 min, RT). Wash.
Add 7-AAD or DAPI for total DNA content. Acquire.

EdU Alternative

EdU (5-ethynyl-2'-deoxyuridine) uses click chemistry instead of antibodies, eliminating the need for DNase denaturation. This results in better preservation of cell morphology and surface markers.

Tip: EdU is generally preferred over BrdU for new experiments because it doesn't require DNA denaturation, preserves epitopes better, and is faster.

18. Multiplex Cytokine Bead Array (CBA) ▼

Purpose

Quantify multiple soluble analytes (cytokines, chemokines) simultaneously from serum, plasma, or culture supernatants using bead-based immunoassays analyzed on a flow cytometer.

Materials

BD CBA Flex Set or LEGENDplex (BioLegend) kit for analytes of interest
Standards, detection reagents, wash buffer
V-bottom 96-well plate or tubes

Procedure

Reconstitute lyophilized standards. Prepare serial dilutions (typically 8-point).
Mix capture beads for all analytes together. Vortex well.
Add 25 µL mixed capture beads to each well.
Add 25 µL of standards or samples.
Incubate 1–2 hours at RT with shaking (or overnight at 4°C).
Add 25 µL detection antibody cocktail. Incubate 1 h at RT.
Add 25 µL SA-PE (streptavidin-PE). Incubate 30 min at RT.
Wash 2x with wash buffer. Resuspend in 200 µL.
Acquire on cytometer. Analyze with FCAP Array or LEGENDplex software.

Tip: Run at least 300 events per bead population for reliable quantification. Vortex bead mixtures thoroughly before each use — beads settle quickly.

19. Whole Blood Lyse/Stain Protocol ▼

Purpose

Perform immunophenotyping directly from whole blood using a lyse/stain or stain/lyse approach, avoiding density gradient separation and preserving all leukocyte populations.

Materials

EDTA or heparin anticoagulated whole blood (fresh, <24 h)
RBC lysis buffer: BD FACS Lysing Solution, ACK Lysis Buffer, or 1x ammonium chloride solution
Fluorochrome-conjugated antibodies

Procedure (Stain-Lyse-Wash)

Aliquot 100 µL whole blood per tube.
Add Fc block if needed (5 min, RT).
Add pre-titrated antibody cocktail. Vortex gently.
Incubate 15–20 min at RT in the dark.
Add 2 mL 1x BD FACS Lysing Solution. Vortex.
Incubate 10 min at RT (until clear/transparent).
Centrifuge 300 × g, 5 min. Decant supernatant.
Wash 1x in 2 mL FACS buffer.
Resuspend in 300 µL FACS buffer. Acquire.

Tip: If lysis is incomplete (remaining RBCs), repeat lysis step once. For intracellular staining, BD FACS Lysing Solution simultaneously lyses and fixes. Follow with permeabilization.

20. Fixable Viability Dye Staining ▼

Purpose

Discriminate live from dead cells using amine-reactive fixable viability dyes, compatible with downstream fixation and permeabilization protocols.

Materials

Fixable viability dye: LIVE/DEAD Fixable (Aqua, Violet, Near-IR, etc.), Zombie dyes, eFluor viability dyes
PBS (protein-free — no FBS, no BSA)
FACS buffer (for post-staining washes)

Procedure

Harvest cells and wash 2x in PBS (protein-free). This is critical — proteins will quench the dye.
Resuspend cells at 1 × 10⁶/mL in PBS.
Add fixable viability dye at recommended dilution (typically 1:500–1:1000).
Incubate 15–20 min at 4°C or RT in the dark.
Wash 1x in FACS buffer (protein will now stop the reaction).
Proceed to surface staining, then fixation/permeabilization as needed.
The viability signal is preserved through fixation and permeabilization.

Caution: Fixable viability dyes MUST be used in protein-free PBS. Even small amounts of BSA or FBS will dramatically reduce dead/live discrimination. Wash cells thoroughly before staining.

🌐 External Protocol Resources

Curated links to published flow cytometry protocols from university core facilities, reagent vendors, and protocol repositories. These resources complement the protocols above with detailed, step-by-step guides.

University & Institutional Core Facility Protocols

Institution	Protocol Topics	Link
Yale University – Flow Cytometry Facility	Surface staining, intracellular cytokine staining, general sample prep	Surface Staining • ICS Protocol
University of Iowa – Flow Cytometry Facility	Comprehensive staining protocols, ICS (2 methods), surface + intracellular combined	All Protocols
University of Arizona – Flow Cytometry Core	Intracellular cytokine staining with permeabilization options	ICS Protocol
UAMS – Flow Cytometry Core	Immunophenotyping, PI cell cycle, BrdU staining, Annexin V apoptosis, intracellular cytokines	All Protocols
UC San Diego – Moores Cancer Center Flow Core	Cell cycle PI staining, general flow protocols	All Protocols
University of Virginia – Flow Cytometry Facility	PI cell cycle, intracellular cytokine staining, general protocols	Cell Cycle (PI)
University of Michigan – Flow Cytometry Core	BrdU/PI cell proliferation, CFSE assays, training resources	BrdU/PI Proliferation
UT Health San Antonio – Flow Cytometry Core	Cell cycle PI protocol with instrument cleaning notes	Cell Cycle Protocol
San Diego State University – Flow Core	Comprehensive protocol collection, counting beads, sample prep	All Protocols
UAB – Rheumatology / Flow Core	Phospho-flow (pSTAT) staining for human PBMCs	Phospho-Flow (PDF)

Reagent & Instrument Vendor Protocols

Vendor	Protocol Topics	Link
BD Biosciences	Comprehensive protocol hub: surface staining, ICS, Phosflow, Treg, cell cycle, compensation	All BD Protocols
BD Biosciences – Phosflow	Phospho-protein detection (pSTAT, pERK, pAKT) in human PBMCs, whole blood, adherent cells	Phosflow Protocols
BioLegend	Surface staining, intracellular staining, phospho-flow, Zombie viability dyes, Annexin V	All BioLegend Protocols
BioLegend – Intracellular Staining	Detailed ICS protocol with Cyto-Fast Fix/Perm buffers	ICS Protocol (PDF)
Thermo Fisher / Invitrogen	Comprehensive flow cytometry protocol hub: viability, surface, intracellular, apoptosis, cell cycle	All Thermo Fisher Protocols
Thermo Fisher – Annexin V Apoptosis	Step-by-step Annexin V / PI apoptosis staining protocol	Annexin V Protocol
Thermo Fisher – Viability Staining	Fixable viability dye staining, whole blood lysis, cell prep	Viability Protocol
Thermo Fisher – Intracellular Antigens	ICS and nuclear antigen staining with eBioscience FoxP3 buffer set	Intracellular Staining
Miltenyi Biotec	Flow cytometry applications, MACSQuant protocols, Inside Stain kits, cell phenotyping	Miltenyi Applications
Beckman Coulter	CytoFLEX optimization, flow cytometry basics and educational resources	Flow Cytometry Basics

Protocol Repositories & Journal Resources

Source	Description	Link
protocols.io – Intracellular Flow Cytometry	Community-shared ICS protocol with step-by-step detail, DOI-citable	ICS on protocols.io
protocols.io – Cell Cycle on CytoFLEX S	PI cell cycle analysis protocol specific to Beckman Coulter CytoFLEX S	Cell Cycle Protocol
Current Protocols – Microbial Viability	Comprehensive protocol for estimating microbial viability using flow cytometry	Microbial Viability
Current Protocols – High-Parameter Overnight Staining	Optimized overnight staining protocol for improved high-parameter flow cytometry	Overnight Staining
STAR Protocols – Blood/Marrow Flow Cytometry	Detailed human blood and bone marrow immunophenotyping protocols	Blood/Marrow Protocols
PMC / PubMed – Annexin V Apoptosis Protocol	Peer-reviewed protocol for apoptosis assay by flow cytometry using Annexin V	Annexin V Protocol
PMC – Phospho-Flow in Adherent Cells	Detailed phospho-protein analysis protocol for adherent cell lines	Phospho-Flow (Adherent)
PMC – Bead-Based Multiplex Assays	Review of multiplex bead array (CBA/Luminex) protocols for diagnostic microbiology	Multiplex Bead Assays
PMC – Bacterial Viability by Flow Cytometry	Safe bacterial viability protocol with fixation step for biosafety	Bacterial Viability
PMC – LIVE/DEAD BacLight + Flow Cytometry	Assessment of bacterial viability using LIVE/DEAD BacLight kit with flow cytometry	BacLight Protocol

Comprehensive Multi-Protocol Resources

Resource	Description	Link
PMC – Guidelines for Flow Cytometry in Immunological Studies (3rd Edition)	The definitive community reference: covers instrument setup, controls, viability staining, surface/intracellular staining, spectral cytometry, high-dimensional analysis, and reporting standards. Over 100 pages of best practices.	Full Guidelines
Colibri Cytometry – Protocol Collection	Community-driven protocol collection covering common flow cytometry applications	Colibri Protocols
Thermo Fisher – Apoptosis Protocol Collection	Comprehensive apoptosis resource: Annexin V, caspase activity, mitochondrial potential, TUNEL, chromatin condensation	Apoptosis Protocols
NCI Frederick – Miltenyi Flow Cytometry Phenotyping	GMP-grade cell phenotyping protocol using MACSQuant with 8-color immunophenotyping	NCI Protocol (PDF)
BD Biosciences – Intracellular Flow Cytometry Brochure	Comprehensive guide covering ICS, Phosflow, transcription factors, and FoxP3 staining with BD reagents	BD ICS Guide (PDF)
BioLegend – Multicolor Flow Cytometry Guide	Panel design, fluorophore selection, antibody titration, and multicolor staining best practices	Multicolor Guide (PDF)

Learning Flow Cytometry

What is Flow Cytometry?

🔬 Fluidics & Hydrodynamic Focusing

💡 Optics & Lasers

📊 Data Analysis & Gating

⚙ Compensation & Controls

Understanding Scatter Plots: FSC vs SSC

The Fluorescence Spectrum

Key Terminology

Event

Fluorochrome / Fluorophore

PMT (Photomultiplier Tube)

MFI (Mean/Median Fluorescence Intensity)

Gating

Panel Design

Flow Cytometry Use Cases

🏥 Immunophenotyping

🔬 Cell Cycle Analysis

☠️ Apoptosis Detection

🏭 Cell Sorting (FACS)

🧬 Intracellular Cytokine Staining

🌎 Microbiology & Virology

💬 Signal Transduction / Phospho-Flow

🩸 Stem Cell Research

💧 Platelet & RBC Analysis

🏭 Clinical Diagnostics

🔨 Drug Discovery & Screening

🌱 Environmental & Marine Biology

Flow Cytometry Instruments

Instrument Categories

🔬 Analyzers

⚖ Cell Sorters

🌈 Spectral Analyzers

📷 Imaging / Mass Cytometers

BD Biosciences

Beckman Coulter Life Sciences

Cytek Biosciences

Thermo Fisher Scientific

Sony Biotechnology

Agilent Technologies

Bio-Rad Laboratories

Miltenyi Biotec

Standard BioTools (formerly Fluidigm)

Sartorius

Sysmex

Stratedigm

Apogee Flow Systems

Flow Cytometry Reagents

Common Fluorochromes by Laser Line

Viability Dyes

DNA & Cell Cycle Dyes

Functional Probes & Indicators

Tandem Dyes & Polymer Dyes

Common Flow Cytometry Protocols

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