Microbiosensor Chip Can Move DNA Molecules

Originally Published MDDI May 2004

R&D DIGEST

Erin Bradford

A new device may help to diagnose illnesses and detect biohazards—by interacting with and manipulating individual DNA molecules. 

Eric Simone, a senior biomedical engineering major at The Johns Hopkins University (Baltimore), has constructed a new type of microchip that can move and isolate DNA and protein molecules. It's possible that, by linking the chip with analysis equipment, a user could identify medical ailments, monitor a patient's health, or even detect viruses or other biohazards before they spread.

Jeff Tza-Huei Wang, PhD, the assistant professor who supervised Simone's work, is optimistic about the device. “There are several applications for this,” Wang said. “We demonstrated that we could concentrate DNA particles to specific regions. So, if we are talking about detection, we will have an advantage, because more molecules will be attracted to the detection regions. In observing those regions, we will have more molecules, which increases the sensitivity of the analysis.”

Simone created the chip with an innovative circular electrode design, which performs effectively in certain bioanalytical applications. The chip has tiny wires, each about one-fifth the diameter of a human hair, embedded in a circular pattern. When connected to a power source, the chip enables the researchers to generate an electric field that transports molecules to a designated area. “Inside the microchamber are some delicate electric wire layouts,” Wang explained. “We apply an electrical field, which comprises different forces. Basically, the electrical field induces the forces to manipulate and transport the individual molecules, so we can bring the DNA of interest to a particular area we want to investigate.”

The chip takes advantage of the natural negative charge possessed by DNA or a surface charge imposed on the molecules. A tiny drop of liquid containing the DNA is placed atop the chip. Then, the electric field guides the molecules to a designated area where they can be analyzed manually under a microscope.

Wang said that combining this technology with other technologies, such as DNA binding or other molecule interactions, could help to diagnose illnesses or other biohazards early.

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