The researchers published their results in two recent journal articles. One, published May 10 in Nanotechnology, describes the physics and engineering of the fluorescence-enhancing material. The other, published April 20 in Analytical Chemistry, demonstrates the effect in immunoassays. In addition to Chou, the authors include post-doctoral researchers Weihua Zhang, Liangcheng Zhou and Jonathan Hu and graduate students Fei Ding, Wei Ding, Wen-Di Li and Yuxuan Wang.
The work was funded by the Defense Advanced Research Project Agency and the National Science Foundation.
The key to the breakthrough lies in a new artificial nanomaterial called D2PA, which has been under development in Chou's lab for several years. D2PA is a thin layer of gold nanostructures surrounded glass pillars just 60 nanometers in diameter. (A nanometer is one billionth of a meter; that means about 1,000 of the pillars laid side by side would be as wide as a human hair.) The pillars are spaced 200 nanometers apart and capped with a disk of gold on each pillar. The sides of each pillar are speckled with even tinier gold dots about 10 to 15 nanometers in diameter. In previous work, Chou has shown that this unique structure boosts the collection and transmission of light in unusual ways -- in particular, a 1 billion-fold increase in an effect called surface Raman scattering. The current work now demonstrates a giant signal enhancement with fluorescence.
In a typical immunoassay, a sample such as blood, saliva or urine is taken from a patient and added to small glass vials containing antibodies that are designed to "capture" or bind to biomarkers of interest in th
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Princeton University, Engineering School