'Nano-Keys' Bind Cell Receptors and Trigger Allergic Reactions

Feb 16, 2006

The tumblers of life continue to click as Cornell University researchers have fabricated a set of "nano-keys" on the molecular scale to interact with receptors on cell membranes and trigger larger-scale responses within cells -- such as the release of histamines in an allergic response.

How cell membranes control cellular function has long been studied but with ambiguous results. However, nanotechnology now gives researchers new tools to understand the role of cell membranes in activating responses within cells.

Barbara Baird, Cornell professor of chemistry and chemical biology, reported this research today (Feb.16) at the annual meeting of the American Association for the Advancement of Science. She is the director of Cornell's Nanobiotechnology Center, which is funded by the National Science Foundation.

One day, Baird said, scientists might use these insights to develop new drug therapies for allergies and other immune responses, high cholesterol and perhaps viral infections.

By understanding a membrane's role in cell function, she explained that these nano-keys could interfere with responses via the membrane interactions, rather than just targeting proteins to block responses. This could lead to designing ligands (molecules that bind to receptors) that trigger a desired response or inhibit an allergic reaction and preventing the release of histamines and other inflammatory mediators.

In her presentation, "Design and Fabrication of Stimuli to Reveal Spatial Regulation of Cellular Signaling," she explained, "We want to understand how the receptors on cell surfaces mediate cellular responses, how cells work on a molecular level."

To study how receptors on cell membranes jump-start cellular responses, Baird and her colleagues chose to work with mast cells. They were chosen because mast cells secrete chemicals and histamines (substances released in allergic reactions that cause runny nose, watery eyes and other characteristic allergy symptoms) and they are the gatekeepers for the allergic immune response. This system can be manipulated experimentally.

Specifically, Baird works with immunoglobulin E (IgE) antibodies, which mount membrane proteins on mast cells to form receptor complexes that sense the environment and sensitize the cell to allergens, which are substances that cause an allergic reaction. Typically, two or more receptors cluster together when they bind with an antigen (allergen or foreign body), and this causes transmembrane activation of enzymes within the cell that eventually lead to the release of histamines.

Such processes begin on the nanoscale (a nanometer equals one-billionth of a meter) -- at the molecular level on the cell's surface and lead to a system-wide response. At present, very little is known about the structural changes caused by receptor clustering that allow cells to sense their outer environment and start cellular processes within the cell.

The so-called nano-keys are surfaces of silicon with a layer of polymer or a thin lipid (fatty molecules that make up cell membranes) bilayer. The surfaces, which are engineered on the micron scale (0.000001 meter; there are 25,400 microns in an inch), are arranged in patterns that contain antigens and cause IgE-receptors to cluster when the cells attach to the surface. This activates the cell's inner machinery.

Said Baird: "In this way, we can control what the cell sees. The cells are binding to the engineered surfaces and getting turned on. We can then see how the cell is organizing itself due to the stimulus."

Collaborators include: David Holowka, Cornell senior scientist in chemistry; and the research groups of Harold G. Craighead, Cornell professor of applied and engineering physics; Dan Luo, Cornell assistant professor of biological and environmental engineering; Christopher Ober, Cornell professor of materials science and engineering; Watt Webb, Cornell's Eckert Professor in Engineering; and Ulrich Wiesner, Cornell professor of materials science and engineering.

Source: Cornell University

Explore further: Physicists develop efficient method of signal transmission from nanocomponents

Related Stories

Designing better medical implants

May 18, 2015

Biomedical devices that can be implanted in the body for drug delivery, tissue engineering, or sensing can help improve treatment for many diseases. However, such devices are often susceptible to attack by ...

Better batteries to break dependence on fossil fuels

Apr 29, 2015

By 2050 world population is projected to reach 10 billion people, and energy needs will double from what we require today. "We are nowhere near ready," said Héctor D. Abruña at a Charter Day Weekend lecture, ...

Cell's protein-making machines shift modes under stress

Apr 23, 2015

Similar to a hybrid car that switches from gas to electric as it drives on major highways and secondary roads, Cornell researchers have discovered that the cell's protein-making machinery, called ribosomes, ...

Female reproductive tract assists swimming sperm

Apr 15, 2015

In mammalian reproduction, sperm have a tough task: like trout swimming upstream, they must swim against a current through a convoluted female reproductive tract in search of the unfertilized egg.

Recommended for you

Artificial muscles get graphene boost

18 hours ago

Researchers in South Korea have developed an electrode consisting of a single-atom-thick layer of carbon to help make more durable artificial muscles.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.