Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine

Flow Cytometry Core

To learn more or schedule resources for this core, please login to iLab.


Director: David L. Haviland, Ph.D.

The Research Institute Flow Cytometry Core facility is located in R6-417 on the sixth floor of The Methodist Hospital Research Institute building.

The core maintains three instruments, a BD LSRII, FACS Fortessa, and FACS AriaII.  These instruments allow scientist to make very concise measurements at the cellular level, evaluate a large number of samples in a short time frame, and gather information on very rare populations of cells.   The Flow Cytometry Core provides analyzer training, instrumentation, technical expertise, and software for flow cytometric analyses and cell sorting.

What Is Flow Cytometry?

Flow cytometry uses fluorescent probes, usually labeled antibodies, to identify cells. Cells or particles tagged with fluorescent molecules enter the cytometer via a fluid stream. The events then pass by a laser, which emits a specific wavelength of light.  The fluorescent signal is detected and amplified, then translated into an electronic signal, which is sent to the computer. Information about the relatvie size and granularity of a cell is recorded and the result is a visual presentation describing an individual or group of cellular events. If needed the cells or particles can be separated by sorting, and further analyzed.   For a more detailed description and additional resources, please see Introduction to Flow Cytometry: A Learning Guide and our section on How Flow Cytometers Work.

What is Cell Sorting?

Cell sorting is different from analysis as it involves the separation and isolation of various cell populations.   Cells can be sorted using flow cytometry or magnetic labeling to differentiate and separate the cell populations, such as a BD FACSAria or Couter Astrios.    Cell sorting is similar to standard flow cytometry except that the stream is vibrated at a frequency that separates it into droplets. These droplets are then charged according to their fluorescent profile and flow through an electric field that sends the charged drops of interest into a collection tube or plate, while the unwanted cells are directed into a waste container. In contrast, the magnetic separation uses a column that is placed under a magnetic field to retain cells labeled with magnetic beads. Cells are loaded onto the column and labeled cells are retained in magnetic field while unlabeled cells pass through. The column can then be removed from the magnetic field to remove the labeled cells, and the negative or positive fractions can then be processed for experimental purposes. Although not as efficient as sorting by flow cytometry, magnetic separation is often used as a means of enriching a population before sorting on a cytometer.

Available Instruments include:

  • BD LSR II Flow Cytometeris configured with 488, 405, 633, and 355 nm lasers and has the ability to detect 8-10 colors.
  • BD FACS Fortessa Flow Cytometeris equipped with 4 lasers (405, 488, 561, and 633 nm).
  • BD FACS AriaII Flow Cytometer(cell sorter) that is housed in the TMHRI building has 6 lasers (355, 405, 488, 550, 630, and 785nm excitation).  Additionally, the instrument will be contained within a Baker Hood for BSL safety of the operator and investigators.
  • A Second BD FACS AriaII Flow Cytometer(cell sorter) that is housed in the TMHRI building has 4 lasers (405, 488, 550, and 630 nm excitation). Additionally, the instrument will be contained within a Baker Hood for BSL safety of the operator and investigators.

Attention Users:  Consultations with FACS specialists are available by appointment and recommended prior to performing experiments.

  • Flow Cytometry core staff will advise on:
  • - Experimental design (choice of fluorochrome, etc.)
  • - Sample preparation
  • - Controls
  • - Instrument and settings for optimal results
  • - Data interpretation
  • - Assistance with manuscript preparation

Core users will need obtain iLab accounts which is tied to funds through MARS. This MUST be worked out before any work is conducted. This can be arranged through your finanical administrators.   If you have any questions or need to establish an account, please contact Brenda Hartman at 713-441-5841 or BHartman@houstonmethodist.org.

Investigators must schedule appointments in advance for services and consultations.   Investigators are expected to have all animal/human study protocols approved prior to using the core facilities.   Appointments can be made by phone, email, or in person.

Contact Dr. David Haviland at 713-441-9233 or dlhaviland@houstonmethodist.org.