Disposable chemical and biological sensors using micro-imprinted stimuli-responsive hydrogel diffraction grating

The paper report a novel optical diffraction chemical and biological sensor using stimuli-responsive hydrogel grating fabricated through ultraviolet (UV)-assisted micro-imprinting technology. Hydrogel grating swells and shrinks upon exposure to the analyte of interest, thus causing to change the periodicity of the grating. This results in a change in diffraction pattern (i.e., size, brightness, and/or location) of a laser beam recognizable to bare eyes. Therefore, the proposed technology provides a novel paradigm for detecting and displaying information in a way that is readily interpreted by an untrained person, with no need for additional detection tools. In addition, the use of the UV-assisted micro-imprinting technology provides a simple and effective method for patterning hydrogel structures at the submicron scale.