Microfluidic Assay For Estrogen

Measuring estrogen levels in breast tissue can be used to identify women at high risk for breast cancer or to monitor the effects of breast cancer therapy. However, the standard methods available are impractical because they require large amounts of tissue. Aaron R. Wheeler, Robert F. Casper, and coworkers of the University of Toronto have now developed a miniaturized, automated, and integrated method using droplet-based digital microfluidics (DMF) to measure estrogen in 1-µL samples (Sci. Transl. Med. 2009, 1, 1ra2). In the DMF technique, droplets containing sample and reagents are moved on a surface by applying electrical potentials to an array of electrodes. With their new device, the researchers were able to extract and quantify estradiol in breast tissue samples from breast cancer patients and in whole blood and serum samples from a healthy woman. These samples are as much as 4,000 times smaller than the samples used in conventional methods such as immunoassays and mass spectrometry. The DMF method also shortens the total analysis time from about five hours to less than 20 minutes.