Portable DNA Array Detection Based On Microwave Mixing
We are developing a DNA hybridization detector based on the microwave mixing scheme of our tunable ACSTM.
To probe a particular pixel of the array, a microwave signal is applied to a selected one (yellow) of several parallel transmission lines (yellow and cyan) by a multiplexer. A second signal at an offset frequency is applied to a selected (also shown as yellow) second orthogonal transmission line on an upper plate. Both frequencies are thus only present at the intersection. The strength of the mixed frequency depends on the contents of the volume in this intersection.
We are assessing various amplification schemes for this measurement, including labeling target DNA molecules with metal colloids. We are optimizing the frequencies chosen by using our tunable AC scanning tunneling microscope.
This detector will work at substantially lower cost than fluorescence detectors currently used for DNA arrays.
It will be field portable -- consisting of 5 chips, two wafers, a battery, and a laptop interface. This will help make DNA array technology available for plant and wildlife biology, for medical tests in the field, and for other uses in the field.
psw
24 October 1998
