by Matthew Chin
The detection of specific DNA sequences is central to the identification of disease-causing pathogens and genetic diseases, as well as other activities. But current detection technologies require amplification by polymerase chain reaction (PCR), fluorescent or enzymatic labels, and expensive instrumentation.
Now, researchers from the UCLA Henry Samueli School of Engineering and Applied Science have developed a device that amplifies the size of a DNA molecule by coupling it to microscale beads that are one-hundredth the size of a human hair. In the presence of the specific DNA sequence to be detected, the beads will produce a large electronic signal that is easily read out by a simple device. This signal is generated because the binding of the specific DNA sequence to the beads gives them a negative charge, attracting them to a small pore, which they block. The electrical measurement of this blockage can be indicated by a simple light-emitting diode in a compact handheld device.
The simplicity and compactness of this new technology may enable low-cost handheld devices for DNA detection without the need for molecular amplification or any additional instrumentation. The method could be used in screening for genetic diseases, food-safety procedures, forensic sciences and other applications.
Authors of the research include UCLA bioengineering graduate student Leyla Esfandiari, UCLA professor of chemical and biomolecular engineering Harold Monbouquette, and UCLA associate professor of bioengineering Jacob J. Schmidt. Monbouquette and Schmidt are also members of the California NanoSystems Institute at UCLA.
The research was supported in part by the National Institutes of Health.
The research is published online in the peer-reviewed Journal of the American Chemical Society and will be included in a forthcoming print issue of the journal.