Understanding Cell Movement
posted 8 March 2013
by Maureen Paisley

What can I do with a degree in science?

Students interested in a career in science often pose the question: “What can I do with a Science degree?”  Although this is certainly a fair question, it is often exceedingly difficult to answer – especially given the rapid changes we see in science. 

Follow your interests – they can take you to surprising places

When Francis Lin (Physics and Astronomy) began his undergraduate degree in applied physics, he had no idea that physics would one day lead him to study immune cell migration, first at the University of California as a graduate student, and later, at Stanford University School of Medicine as a postdoc fellow. Microfluidic cell migration research was still in its early stages when he began his PhD, but over the years has grown into an important area with many research labs, hundreds of publications and companies making commercial products. His early involvement in this area and his interdisciplinary training paved the way for the research he undertakes today on immunotrafficking at the University of Manitoba.

What does cell movement have to do with physics and why is it important?

On the most basic level, physicists study motion, and in Lin’s case, he studies the movement of cells within the body.  His research group in the Immuno Trafficking Lab, uses a multidisciplinary approach to better understand how the movement of immune cells is guided by chemical and electrical signals.  The group has already found interesting connections among physics, engineering, biology and immunology in their research.

Cell movement or migration plays important roles in processes like immune responses, wound healing and cancer metastasis.  If scientists can understand how cells move in the body and how their movement is directed, they can potentially encourage cell movement (as in facilitating wound healing) or prevent cell movement (as in controlling cancer metastasis and autoimmune diseases).

What does the Lin group do?

The Lin research group designs microfluidic devices and uses them in their research.  These devices have small channels with micrometer dimensions where scientists can precisely control external factors to which cells respond.  In particular, they are interested in two important factors that can guide cell movement: chemical concentration gradients and electric fields.

Chemical concentration gradients

Chemical concentration gradients are one of the factors that guide the movement of various cell types (chemotaxis).  White blood cells, for example, are able to detect and then follow chemical gradients in tissues.  These white blood cells are then directed to perform their immune functions, but misdirected cells can cause disorders such as autoimmune diseases.
   
Using microfluidic devices, Lin’s research group quantitatively studies the movement of cells exposed to precisely-controlled chemical gradients. Particularly, they use microfluidic devices to construct rather complex chemical fields to better simulate conditions in the body, and study how cells make directional decisions in response to the chemical fields.

For example, microfluidic experiments help us understand how chemical gradients control the movement of immune cells in lymph nodes.  Then mathematical models are used to explain and ultimately predict cell movement.

Electric fields

Using microfluidic devices, the team is also working on understanding how cells respond to electric fields. For example, electric fields are produced in the body by wound tissue, and a broad range of cell types can migrate in response to electric fields (electrotaxis). The Lin group has shown electrotaxis of different immune cells, which may aid in processes like wound healing. The group is extending their electrotaxis research to other cell types such as cancer cells and stem cells, and again, they are developing mathematical models to explain and make predictions about cell behaviour.

In addition to studying the processes of chemotaxis and electrotaxis individually and developing predictive models of cell behaviour in each, the group is working on investigating more complex environments, where chemical gradients and electric fields co-exist, and the two may collaborate or compete to guide cell movement. Microfluidic devices and mathematical models have been developed for research in this direction.

Where will this lead?

It is the goal of the research group to gain a better understanding of cell behaviour, particularly directed cell movement, in increasingly complex environments such as the human body. They believe that building the complexity of the guiding environments, in a controlled manner, and investigating cell behaviour, using quantitative approaches, will have a profound impact on life science research targeting both basic science questions and clinical applications.


RELATED LINKS



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Dr. Francis Lin pictured with the research group's confocal microscope, specifically configured for imaging cell migration in microfluidic systems.


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Master of Science student Jing Li and undergraduate student Nitin Wadhawan collaborated on developing a new microfluidic device for cell migration studies.  The monitor displays cell pictures from their device.


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Dr. Francis Lin and Jing Li