Surgeons treating cancer patients may soon have instant information about what tissues to remove as a result of research in Cork. A device that gives on-the-spot checking during surgery for the presence of cancer cells is under development by scientists at the National Microelectronics Research Centre (NMRC), University College, Cork.
The work is based on microfluidics, a relatively new branch of biotechnology that works at the boundaries of physics, chemistry, microelectronic engineering, information technology, biology, and biotechnology itself.
The surgeon will be able to collect a few cells and insert them in a device that looks like a computer microchip. If cancerous, the cells will absorb a special dye, and light from a tiny on-chip laser will cause them to fluoresce. Non-cancerous cells will not fluoresce, so the surgeon will have almost-instant information on the patient's condition. Cells of interest can then be separated for more detailed analysis.
Microfluidics deals with the manipulation of liquids in nano and pico-litre amounts, as small as one 50-millionth of a drop of water. Being able to handle such tiny amounts of liquid offers big advantages when working with toxic, expensive or scarce fluids. The fluid under study is placed in tiny channels, 50 to 100 microns wide - approximately the width of a human hair. It can then be made to move in various directions by air pressure or electrical forces.
Tiny integrated components, such as semiconductor lasers, microelectronic circuits, micropumps, microvalves and microheaters can be placed on the chip to perform various functions, and the processes can be computer-controlled.
"When fluidic channels are shrunk to micron dimensions, the fluids behave in a predictable manner, like fluidic circuits," says Dr Peter O'Brien, leader of the microfluidics team at the NMRC. "The design principles are essentially the same as for electronic chips." "Microfluidics is not simply small-scale plumbing, as it involves integrating functionality on to the chip," Dr O'Brien explains. "We can use the expertise in microelectronics at NMRC to simulate the chip, design it, fabricate it and test it.
"When we make the devices in the clean room, we can then see if the software simulations are correct, and feed back the results into the design. We use the same design software to lay out our fluidic circuits as is used in microelectronics," Dr O'Brien says. The cancer cell detection chip is to be reusable and silicon-based, but Dr O'Brien envisages that at a later stage a disposable chip based on polymer could be designed for use by a general practitioner.
Although microfluidics is relatively new, research groups worldwide are working in the area. For example, microfluidics techniques were used in the Human Genome Project to speed up DNA mapping.
The Cork team is also working on devices for rapid analysis of DNA, and it is developing improved methods for discovering new pharmaceutical drugs and for environmental monitoring. "One and a half billion different compounds were tested by the pharmaceutical industry last year in an effort to find new drugs, and the number is growing," he says. The team has already designed and fabricated chemical microreactors on chips.
The next step is to build much more complex systems with a number of microreactors where semiconductor lasers control fluid movement. It is expected that prototypes for these devices will be available within a year, while the cancer-detection system prototype will take two years.
The NMRC began life with an exclusive focus on microelectronics, but expanded to take in biosensors. Biosensors use microelectronics to measure biological functions and data, and are valuable in health care and environmental monitoring.
This marriage of information and communications technologies with life sciences means that there is a body of experience in the NMRC on which the microfluidics team can draw.