Studying Small Molecule Transport Across the Cell Membrane
Dr. Douglas Kell, Research Chair in Systems Biology at the University of Liverpool, studies the uptake of fluorescent small molecules across the plasma membrane. His work requires fast screening of up to 50 fluorophores at once, which can be a challenge. He found the solution in advanced flow cytometry.
This article is posted on our Science Snippets Blog
Drug Transport Through the Membrane
The plasma membrane is what separates the interior of the cell from the external environment. It consists of a lipid bilayer as well as other macromolecules like carbohydrates, glycoproteins and membrane proteins, that collectively provide structure, and regulate the transport of molecules across the cell.
The path of a drug molecule into the cell depends on its physical and chemical properties. Most lipid soluble drugs, for example, can cross the membrane passively using the process of diffusion. Other drugs enter the cell either passively, or actively by mimicking the natural substrates of transporter proteins.
Knowing which transporter(s) a drug uses, helps scientists better predict potential drug interactions, treatment efficacy, and resistance mechanisms.
Dr. Douglas Kell’s Work on Small Molecule Transport
Dr. Kell’s lab is interested in the transport of small molecules across cellular membranes. His research not only focuses on mammalian cell membrane transporters, but also bacterial transporters, many of which are not yet characterized. His group uses advanced flow cytometry to detect the uptake of small fluorescent molecules, which they have previously shown to have a high degree of structural similarity to many small molecule pharmaceuticals.
The aim of one study is to identify the molecular transporters responsible for the uptake of psychoactive drugs into mammalian cells. To answer this question, they have developed competitive assays between the drugs of interest and their fluorophore mimics. They use advanced flow cytometry to quantify cell transport into mammalian cells with specific transporter proteins being knocked out.
Why High Throughput Flow Cytometry
The Kell lab uses the iQue® Advanced Flow Cytometry Platform for their studies and like it for several reasons:
- High throughput: the iQue® can handle 96 and 384 well plates, so they can screen many fluorescent small molecules at once
- Rapid analysis: the instrument is known for being one of the fastest flow cytometers, helping them get more done in a day
- Performance: the system gives robust data, making it easy to detect intracellular fluorescence signal without interference from extracellular noise
- Versatility: it can detect small cells, so they can study the membrane biology of both mammalian cells and E.coli
Other projects in the lab include screens of up to 50 fluorophores for transport into E. coli cells, and use of fluorophores to detect proliferation of microbial cells after treatment with various antibiotics, with the ultimate goal of developing a rapid, anti-microbial susceptibility test for urinary tract infections. Watch the video below to learn more about the ongoing research in the Kell lab.
