Acoustic-Focusing Flow Cytometer

What is the Acoustic-Focusing Flow Cytometer?

An acoustic-focusing flow cytometer uses ultrasonic standing waves to position cells in the center of the flow stream before laser interrogation. This permits high sample flow rates, lower clogging risk and accurate counting of dilute or small-volume samples without relying only on hydrodynamic sheath.

Overview

Acoustic-focusing cytometers add a piezoelectric transducer that generates an ultrasonic standing wave in a capillary, driving cells to the pressure node at the center of the flow. Because focusing does not depend on sheath dilution, sample can be run at much higher flow rates, often up to 1,000 microliters per minute, while retaining tight core streams and low coefficients of variation. The approach is useful for dilute samples such as bacteria, environmental water and low-concentration cell suspensions, and for long acquisitions of rare events. Many systems use volumetric syringe pumps or peristaltic pumps to give absolute counts without counting beads. Configurations usually offer one to four lasers and up to 13 or so fluorescence parameters, making them mid-range analyzers with strong counting performance.

How does it work?

A flow cytometer uses sheath fluid to hydrodynamically focus a sample into a narrow core stream so cells cross the laser interrogation point one at a time. Scattered light is collected at small angles (forward scatter, related to size) and at 90 degrees (side scatter, related to granularity). Fluorochromes are excited by lasers, commonly 405, 488, 561 and 640 nm, and emission is split by dichroic filters and bandpass filters to photomultiplier tubes or photodiodes. Conventional instruments assign one detector per fluorochrome and apply a compensation matrix, whereas spectral instruments capture the full emission spectrum and unmix it mathematically. Electronics digitize pulse height, area and width, and software records list-mode FCS files for gating and statistical analysis.

What are the key features?

• Ultrasonic standing wave positions cells at the capillary center before detection
• Sample flow rates up to about 1,000 microliters per minute with low CV
• Volumetric pumping provides absolute cell counts without counting beads
• Reduced clogging risk for fibrous or aggregated samples compared with small-orifice flow cells
• One to four lasers with up to about 13 fluorescence parameters
• Fast acquisition of rare events from low-concentration samples

What are the technical specifications?

A typical acoustic-focusing flow cytometer configuration offers focusing method of Acoustic standing wave plus sheath, laser configuration of 1–4 (405/488/561/640 nm), fluorescence parameters of Up to 13, sample flow rate of 10–1,000 µL/min, maximum event rate of Up to 50,000 events/s and absolute counting of Volumetric, no beads required. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Acoustic-Focusing Flow Cytometer is used in bacterial and phytoplankton counting, rare-event detection in dilute samples, environmental water monitoring, cell line viability and counting and high-throughput plate screening. Across the wider Flow Cytometers class, laboratories also deploy it for immunophenotyping of lymphocyte subsets, CD34 stem cell enumeration and cell cycle and apoptosis analysis.

Which standards and certifications apply?

Relevant standards and methods include CLSI H62, CLSI H43, ISO 20391-1, IEC 61010-1, IEC 61010-2-101, IEC 60825-1 and ISAC FCS 3.1. Certification candidates for this model are CE, IEC 61010-1 compliance and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Install the cytometer on a vibration-free bench with stable power and ambient temperature between 15 and 30 degrees Celsius, and provide waste handling for potentially biohazardous effluent, typically with bleach treatment. Run daily quality control using fluorescent beads to verify laser alignment, sensitivity and coefficient of variation, and keep Levey-Jennings style records of detector voltages. Perform daily and weekly fluidics cleaning to avoid clogging, and replace sheath filters and tubing on schedule. Laser power and optical alignment should be checked by trained service staff at least annually. Laboratories working under ISO 15189 or GLP should enable audit trails, electronic signatures and validated software updates.

How do I select the right Acoustic-Focusing Flow Cytometer?

Choose acoustic focusing when samples are dilute, when absolute counts are needed without beads, or when long acquisition of rare events would otherwise take too long. For panels above 13 colors select a high-parameter analyzer. In an RFQ specify maximum flow rate, counting accuracy, laser set and pump type.

How does it compare with other Flow Cytometers variants?

Select a cytometer by panel complexity, sensitivity and workflow. Define the maximum number of simultaneous colors, then choose laser and detector count to match; conventional filter-based systems are simple for 4 to 12 colors, while spectral systems ease panel design beyond 20. Check resolution of dim populations, small particle detection and event rate, typically 10,000 to 100,000 events per second. Consider footprint, whether a compact personal analyzer or a full research platform is required, and whether an acoustic focusing or plate loader is needed for throughput. Verify that software provides compensation or unmixing, batch analysis and user access control. For clinical use, confirm that the supplier can support IVD documentation, calibration beads and a validated quality control routine.