Q&A With Florin Tuluc, MD, PhD, Director, Flow Cytometry Core

Florin Tuluc, MD, PhD

Editor's note: Children's Hospital of Philadelphia Research Institute supports a variety of Core Facilities providing services ranging from high-tech solutions, such as single cell sequencing and data analysis to filling personnel-based needs for research teams. All the CHOP Cores are designed to enhance the work of our research community, enabling principal investigators and their staff to reach their project goals in partnership with the expertise of the Cores' staff. In each installment of this quarterly series called Tour the Cores, you will meet a different Core Facilities director and get acquainted with how their Core can promote your project's success.

What is your professional background and how did your path lead to Children's Hospital of Philadelphia?

In 2000, I moved to the United States for a postdoctoral position at Temple University. I first encountered flow cytometry as part of the techniques I needed to use during my research on the role of purinergic receptors on granulocytes, and on general innate immunity. In 2005, I joined a team of investigators at CHOP interested in the role of innate immune cells in HIV. The opportunity to lead a reorganization of the Flow Cytometry Core Lab arose in 2010. It was an exciting chance to learn and develop my skills while helping other researchers with their projects.

Before coming to the U.S., I studied medicine at the University of Medicine and Pharmacy in Iaşi, Romania, then held an academic position teaching pharmacology. A research position in the Pharmacology Institute in Freiburg, Germany, followed, where I developed novel antagonists at purinergic receptors.

When was the Core established, and how has it grown since its inception and under your leadership?

When I began leading the Flow Cytometry Core, our lab consisted of two analyzers and an outdated cell sorter to serve approximately 25 researchers, and scheduling was done with pencil and paper. The Core currently has eight analyzers and eight cell sorters, which were used by more than 1,000 researchers from more than 300 labs in the past three years. CHOP researchers comprise about two-thirds of our customers, and University of Pennsylvania researchers account for about one-third.

Since 2010, year after year CHOP Research Institute funded the purchase of many large state-of-the-art instruments and several major upgrades, including starting with the purchase of an LSRFortessa cell analyzer, which has since been upgraded to have five lasers and 18 fluorescence detectors, and a BD Accuri cytometer. In 2012, a well-known cell sorter manufacturer installed a MoFlo XDP cell sorter in the Flow Cytometry Core Lab that proved so popular among CHOP researchers that the Research Institute funded the purchase of our first sorter, the MoFlo Astrios EQ, which was permanently installed in the lab. These investments were driven by the need of more capacity for flow analysis and cell sorting, as this technology gained popularity due to its versatility and wide applicability.

The Flow Cytometry Core Lab also has three Aurora spectral analyzers and two Aurora spectral sorters. The analyzers are instruments that use a more complex mathematical algorithm called linear unmixing to separate the colors emitted by each cell. This spectral unmixing, combined with the detection capability of the device's optics and electronics, enable the analysis of samples containing more than 40 different fluorochromes without the need for reconfiguration.

I am extremely grateful to Robert Doms, MD, PhD, pathologist-in-chief at CHOP, for his support of the Flow Cytometry Core. His department's generous contributions enabled the acquisition of two additional cell sorters and three cell analyzers, all of which are heavily used by our research community.

What makes your Core team exceptional?

A key element of the Flow Cytometry Core Lab’s success is our team of technical specialists. Since 2011, my team has grown from 1.5 employees to eight people with more than 50 years of combined flow cytometry experience.

We are motivated by the hundreds of researchers who visit our lab to use our cytometers, have their cells sorted, or ask for advice on how to design or troubleshoot their experiments.

We do our best to understand what each researcher needs and provide the assistance that helps them advance their science. This is very rewarding to me and all the members of the Flow Cytometry Core Lab.

We ensure that our instruments and staff are prepared to get work done promptly, a necessity for cell sorting projects, which almost exclusively involve separating live cells and must be processed within the same day they are prepared, so our readiness is essential. The cytometers in the lab are available 24/7 to all CHOP researchers, with access from 6 a.m. to 6 p.m. for researchers from the University of Pennsylvania.

What would you like potential customers to know about working with your Core?

A common misconception among researchers who are new to flow cytometry is also a fun fact about the field. When Leonard Herzenberg, PhD, and his team at Stanford University developed the first flow cytometer in the late 1960s, the technology was called FACS (Fluorescence-Activated Cell Sorting), because at that time the most important use of the newly invented device was sorting cells.

Years later, these devices were improved to detect many fluorochromes simultaneously. The applicability for analyzing complex cellular mixtures without necessarily separating the cells became obvious, and the FACS name was replaced with the more encompassing "flow cytometry."

Old habits are hard to break, and some researchers still use the term "sorting" when they mean flow cytometry analysis. When a researcher comes to our lab for the first time and talks about "FACS" or "sorting," we are careful to confirm whether they want the cells physically separated or only analyzed.

Any additional facts or items of interest to the research community?

I would like to emphasize the outstanding capabilities of the three Aurora spectral analyzers and two sorters we have in our lab. These advanced devices receive a great deal of use. I invite all researchers who use our lab to let us know about their publications so we can share their success on our website.

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