Abstract: A sensor comprises respective acceptor and donor compounds immobilised in or on a matrix including a glucose-binding boronate and a cationic species, whereby the spacing between the acceptor and donor compounds is reduced in the presence of glucose. For example a holographic sensor comprises a glucose-binding boronate and a cationic species held within the sensor.

Abstract: An ophthalmic device which comprises a holographic element comprising a medium comprising a phenylboronic acid group and, disposed therein, a hologram, wherein an optical characteristic of the element changes as a result of a variation of a physical property of the medium, and wherein the variation arises as a result of interaction between the medium and an analyte present in an ocular fluid.

Abstract: A sensor for the detection of an analyte, comprising a holographic element comprising a medium and a hologram disposed throughout the volume of the medium, wherein an optical characteristic of the hologram changes as a result of a variation of a physical property occurring throughout the volume of the medium, wherein the medium is obtainable by formation in situ in the presence of a pore-forming agent, wherein the agent is not present in the sensor or does not react with the analyte and the sensor.

Abstract: A holographic sensor comprising a thin film polymer matrix that undergoes a change in response to a substance to be sensed, the matrix containing within its volume a set of two or more holographic recordings, each recording providing a holographic image when the sensor is illuminated, wherein the presence or appearance of each image is visible to the eye as a function of the response of the sensor to the substance to be sensed. The images provide the dynamic range of the sensor. Such a sensor can be used to provide a visible image that changes or appears to the eye in response to an analyte.

Abstract: A sensor for the detection of an analyte comprising a cis-diol moiety, which comprises a holographic element comprising a medium and a hologram disposed throughout the volume of the medium, wherein an optical characteristic of the element changes as a result of a variation of a physical property occurring throughout the volume of the medium, and wherein the medium is a polymer comprising a group of formula (I): wherein n is 0, 1, 2, 3 or 4; each X (if present) is independently is an atom or group which, via an electronic effect, promotes formation of a tetrahedral geometry about the boron atom; and Y is a spacer which, when n is 0 or otherwise optionally, is an atom or group which, via an electronic effect, promotes formation of a tetrahedral geometry about the boron atom. Such a sensor may be used for the detection of glucose.

Abstract: An ophthalmic device which comprises a holographic element comprising a medium comprising a phenylboronic acid group and, disposed therein, a hologram, wherein an optical characteristic of the element changes as a result of a variation of a physical property of the medium, and wherein the variation arises as a result of interaction between the medium and an analyte present in an ocular fluid.

Abstract: An array of discrete sensors disposed on a substrate, each sensor comprising a holographic support medium and a hologram disposed throughout the volume of the medium, whereby interaction with an analyte results in a variation of a property of the medium.

Abstract: A method for the detection of an analyte in a fluid, comprising contacting the fluid with a holographic element comprising a medium and a hologram disposed throughout the volume of the medium, wherein an optical characteristic of the element changes as a result of a variation of a physical property occurring throughout the volume of the medium, wherein the variation arises as a result of interaction between the medium and the analyte, and wherein the reaction and the variation are reversible; and detecting any change of the optical characteristic.

Abstract: A holographic or diffraction device responsive to interrogation, the device comprising an image-former and an image-concealer; wherein the image-former is adapted such that light reflected from or transmitted through it forms at least one image; wherein the image-concealer acts to attenuate the image; and wherein the attenuation of the image by the image-concealer is alterable responsive to interrogation