Patent ID: 8663563

Claim:
A reflective diffractometric hydrogel sensor comprising: an upper layer comprising: a microfluidic chamber formed from a substantially transparent material, bounded by an upper layer substrate on one surface, and configured to contain a solution; a reflective diffraction grating, positioned within the microfluidic chamber, comprised of a plurality of hydrogel strips each having a top surface and a bottom surface, wherein each top surface is coated with a reflective material and each bottom surface is in contact with the upper layer substrate, and the hydrogel strips being configured to change in dimension in response to a stimulus; and a reflective surface below the reflective diffraction grating comprising the reflective coating of the plurality of hydrogel strips; wherein when a coherent light is incident upon and reflected from the reflective surface and the top surface of the upper layer at an angle substantially normal to the upper layer an interference diffraction pattern results, comprised of a first diffraction mode, a light intensity of which indicates the relative distance between the top surfaces of the plurality of hydrogel strips and the reflective surface.