CytoFLEX SRT Flow Cytometer with Cell Sorting Capability

Overview

The CytoFLEX SRT is a benchtop flow cytometer engineered by Beckman Coulter for high-parameter, high-fidelity cell sorting in academic, pharmaceutical, and clinical research laboratories. It integrates the optical sensitivity and multicolor detection capability of the CytoFLEX platform with robust electrostatic droplet-based sorting technology. Based on the principle of hydrodynamic focusing and laser-induced fluorescence excitation, the system enables real-time detection of up to 15 independent fluorescence parameters using up to four spatially separated solid-state lasers (405 nm, 488 nm, 561 nm, and 638 nm). Cells are interrogated at the beam intersection point, and subsequent charge induction and droplet deflection enable precise, index-sorted deposition into standard 96-well plates or tubes. Its vertical sorting architecture minimizes shear stress during droplet formation and trajectory, contributing to enhanced post-sort viability—particularly critical for functional assays, single-cell genomics, and primary cell culture applications.

Key Features

• High-Parameter Detection: Supports up to 15-color immunophenotyping through optimized optical filter sets and low-noise, high-quantum-efficiency photodiodes and PMTs.
• Rapid System Initialization: Achieves full operational readiness—including fluidics priming, laser alignment verification, and calibration—in ≤21 minutes from cold start, reducing daily workflow latency.
• Flexible Sorting Architecture: Delivers four-way electrostatic sorting with programmable hybrid modes: purity mode (maximizing target cell fidelity), enrichment mode (optimizing yield), and single-cell index sorting with position tracking.
• Viability-Optimized Fluidics: Utilizes a 100 µm quartz nozzle and ultra-low sheath pressure (as low as 15 psi), minimizing turbulent shear forces and preserving membrane integrity during droplet generation and deflection.
• Benchtop Integration: Compact footprint (W × D × H: 61 × 66 × 51 cm) supports placement in biosafety cabinets or shared core facility spaces without dedicated HVAC or floor reinforcement.

Sample Compatibility & Compliance

The CytoFLEX SRT accommodates a broad range of suspension-based biological samples—including peripheral blood mononuclear cells (PBMCs), dissociated tumor tissue, cultured adherent cell lines, and microbial populations—provided they are filtered to ≤40 µm prior to loading. Sample introduction is compatible with standard 5-mL polystyrene tubes, 15-mL conical tubes, and automated plate handlers supporting ANSI/SLAS-compliant 96-well microplates. The instrument complies with IEC 61010-1:2010 for laboratory equipment safety and meets electromagnetic compatibility requirements per FCC Part 15 Class B and CE directives. For regulated environments, optional audit trail logging, user access controls, and electronic signature support align with 21 CFR Part 11 readiness when deployed with compliant LIMS or ELN integration.

Software & Data Management

Acquisition and analysis are managed via CytExpert SRT software—a Windows-based application offering real-time histogram gating, Boolean logic, and automated compensation matrix calculation using single-stained controls. Sorting templates can be saved, versioned, and exported for cross-platform reproducibility. All sorting events are logged with timestamp, droplet delay calibration status, voltage settings, and well-position mapping. Raw FCS 3.1 files are generated with embedded metadata including instrument configuration, operator ID, and acquisition date/time. Data export supports CSV, PDF, and image formats; API endpoints allow integration with enterprise data warehouses or cloud-based analytics platforms for longitudinal cohort analysis.

Applications

• Isolation of rare immune subsets (e.g., antigen-specific T cells, regulatory T cells, or tissue-resident memory T cells) for downstream RNA-seq or ATAC-seq.
• Single-cell cloning of monoclonal antibody-producing hybridomas or CHO cell lines under GMP-aligned workflows.
• Functional sorting based on calcium flux, mitochondrial membrane potential, or caspase activation using ratiometric dyes.
• Microbial population resolution in mixed cultures using nucleic acid stains combined with metabolic probes.
• Quality control of CAR-T or NK cell manufacturing batches via simultaneous viability, transduction efficiency, and activation marker assessment.

FAQ

What is the minimum recommended sample volume for reliable sorting?
A minimum of 100 µL of filtered, single-cell suspension (≥1 × 10⁵ cells/mL) is advised to ensure stable fluidics and sufficient event statistics for gate validation.
Can the CytoFLEX SRT perform single-cell deposition into 384-well plates?
No—the system is validated for 96-well plate formats only. Support for 384-well plates requires hardware modification not offered by Beckman Coulter for this model.
Is UV laser option available for this platform?
No—UV excitation (e.g., 355 nm) is not supported. The fixed laser lineup consists of 405 nm, 488 nm, 561 nm, and 638 nm diodes.
Does the system include sterile sorting capability?
Sterile sorting is achievable when operated inside a certified biosafety cabinet using pre-sterilized collection tubes or plates, though the instrument itself is not ISO 5-certified for cleanroom use.
How is droplet delay calibrated?
Droplet delay is automatically determined using fluorescent beads during startup and may be re-calibrated manually using the CytExpert SRT Delay Wizard prior to each sorting run.