High-speed label-free multianalyte detection through microinterferometry

Interferometers can detect optical path changes down to a billionth-lambda at the half intensity point at quadrature, (defined when the signal and reference waves are out of phase by ninety degrees). We have fabricated interferometric microstructures on silicon all operating at quadrature. The ultimate capability of this approach is the fabrication of over a billion interferometric biosensors on a single spinning disk having the capacity for mega-samples per second sampling speed. As an initial proof of principle of this technique, we have detected the presence of immobilized anti-mouse IgG and the specific binding of mouse IgG at a sampling rate of 100kiloSamp/sec, while non-specific binding observed was low. We will demonstrate that this technique provides a label-free method that may rapidly screen thousands of proteins per assay.