Oct. 5, 2000
Vol. 20 No. 2

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    Microelectronics, biology meet in lab of chemistry professor Mrksich

    By Steve Koppes
    News Office

    University scientists are showing that the ability to build prosthetics, biological warfare sensors and other medical devices that combine microelectronics with biological components, such as cells and proteins, may be a possibility in the future.
    Milan Mrksich, Associate Professor in Chemistry, is working with a group of 15 researchers to combine the technologies of miroelectronics and biotechnology. The group is pioneering the application of surface chemistry to materials science and the control of cellular behavior.

    “The technologies underlying microelectronics and biotechnology are completely different,” said Milan Mrksich, Associate Professor in Chemistry. “That means it’s difficult to combine these two technologies into some common application or technology.”

    Nevertheless, Mrksich’s group of 15 researchers, mostly comprised of graduate students, is learning how to join cells with manufactured materials, how to convert electrical signals into biological ones, and how to identify a particular cellular activity and convert it into an electrical signal a microprocessor can read.

    Mrksich discussed his work last month at the first BioMEMS and Biomedical Nanotechnology World conference at Ohio State University. It was the first-ever comprehensive conference devoted to two growing disciplines that may revolutionize medicine: micro- and nanotechnology.

    Mrksich’s research group is pioneering the application of its specialty, surface chemistry, to materials science and the control of cellular behavior. Surface chemistry becomes increasingly important as biomedical devices become more miniaturized, said Christopher Chen, assistant professor of biomedical engineering and oncology at Johns Hopkins University in Baltimore, Md.

    Within a few years, Chen predicts, such miniaturization technologies will be broadly incorporated into biomedical instruments used for drug discovery and medical diagnostics, as well as cheap portable devices that can monitor anything from blood chemistries to bacteria in ground beef.

    “We’re at the beginning of a whole new phase of engineering research, where traditional physical science and technology fields, such as surface chemistry and micro- and nanofabrication, are being driven by real-world applications in medicine and biology,” Chen said. “Tools that are able to control the chemistry of the surface are very much needed for the next generation of products to move forward. Milan is one of the leading innovators in this field.”

    Mrksich and his team design electrically active surfaces that enable them to control cell adhesion and cell migration in an experimentally clean, systematic way.

    “That’s a nice way of studying how potential drugs would affect cell migration,” said Mrksich, who serves as a scientific advisory board member for three biotechnology companies. “In cancer, cell migration is a key element that leads to the spread of a tumor. A lot of anticancer drugs function by blocking migration of tumor cells. It’s important for the pharmaceutical companies to have tests that evaluate molecules for their ability to block cell migration.”

    More recently, Mrksich has begun to experiment with ways to take the process one step further, electrochemically controlling cellular function via the stimulation of specific proteins.

    He also is developing cell-based sensors and learning how to integrate cells with electronics so the cell itself serves as a sensor. The goal is to design a device that will generate an electrical signal after a cell becomes infected with a hazardous agent such as anthrax or smallpox. Such sensors could detect an exposure days before the victims would begin to show symptoms.

    “It’s very difficult to make man-made sensors that can detect those agents at low levels quickly and reliably. At the same time, cells are very good at detecting these agents because they are the natural victim of those agents,” Mrksich explained.

    Even today, pharmaceutical companies use cells as sensors in a different application–drug testing and development. “By building devices that can more rapidly and accurately tell us how the cells respond to potential drugs, we can know if the drugs are toxic before we go to clinical trials, and we can better understand what side effects they might have before we test them in people,” Mrksich said.

    Mrksich’s work also could benefit the development of prosthetic devices for people who have lost control of muscles because of damaged nerves or spinal cords. It would be possible, in theory, to engineer an implantable device that re-establishes connections with neurons, allowing the brain to again link to and control a muscle. The challenge, Mrksich said, is to learn how to connect an electronics component with neurons so the component recognizes when a neuron fires, then relays that signal, causing another neuron or a muscle to fire.