WASHINGTON, May 26Vanderbilt University engineers have created a "spongy" silicon biosensor that shows promise not only for medical diagnostics, but also for the detection of dangerous toxins and other tiny molecules in the environment. This innovation was originally designed to detect the presence of particular DNA sequences, which can be extremely helpful in identifying whether or not a person is predisposed to heart disease or certain kinds of cancer. The new sensor is described in the Optical Society's open access journal, Optics Express.
Biological chemical sensors save lives by detecting dangerous substances in the environment or specific molecules in the blood that could signal life-threatening diseases. Current sensor technologies, however, are limited because of their large size compared to the extremely minute sizes of some of the chemicals to be detected. In most cases, when attempting to sense something very small with a large sensor, the small molecules don't perturb the sensor's properties enough for detection.
As Vanderbilt University's Xing Wei, a graduate student, and Sharon M. Weiss, an associate professor of electrical engineering and physics, report in Optics Express, it's possible to eliminate this challenge by making sensors with features that are comparative in size to the molecules being detected, greatly increasing the sensitivity of current sensing technology.
To do this, the engineers turned to a porous silicon material, which acts essentially as a small sponge that can then be "seeded" or filled with all sorts of substances that change its propertiesresulting in a detector that's highly sensitive to small molecules (See Figure 1). Capturing a particular sequence of DNA involves seeding the sensor with a single strand of DNA, so that only the complementary strand can attach to it and everything else gets rinsed away.
Why use a porous silicon material? Weiss and Wei stress the sig
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