A device configured to measure, at one or more time points, one or more properties or changes in properties of a fluid sample, the device comprising: a chamber comprising a physical element capable of oscillating, said physical element comprising a suspended element and at least two compliant structures (108 and 109), said chamber defining an internal volume of the device adapted to receive and retain the fluid sample; a plurality of layers, said plurality of layers comprising at least a first layer below the chamber, at least a second layer above the chamber, and a substrate layer between the first and second layers such that the substrate layer comprising the physical element (107, 108 and 109) is in between said plurality of layers, wherein: the substrate layer is linked to said suspended element, said suspended element being not substantially metallic and located within the chamber; the suspended element is linked to the substrate layer by said at least two compliant structures (108 and 109) located within the chamber; and the suspended element is configured to oscillate upon application of an actuating signal to at least one electrically conductive path, which runs across at least two of the compliant structures (108 and 109) and the suspended element; characterised in that: the suspended element comprises an insulating material and at least one patterned conductive layer providing the at least one electrically conductive path which runs across the suspended element, said suspended element having a total metal content less than 50% by weight. a chamber comprising a physical element capable of oscillating, said physical element comprising a suspended element and at least two compliant structures (108 and 109), said chamber defining an internal volume of the device adapted to receive and retain the fluid sample; a plurality of layers, said plurality of layers comprising at least a first layer below the chamber, at least a second layer above the chamber, and a substrate layer between the first and second layers such that the substrate layer comprising the physical element (107, 108 and 109) is in between said plurality of layers, wherein: the substrate layer is linked to said suspended element, said suspended element being not substantially metallic and located within the chamber; the suspended element is linked to the substrate layer by said at least two compliant structures (108 and 109) located within the chamber; and the suspended element is configured to oscillate upon application of an actuating signal to at least one electrically conductive path, which runs across at least two of the compliant structures (108 and 109) and the suspended element; the substrate layer is linked to said suspended element, said suspended element being not substantially metallic and located within the chamber; the suspended element is linked to the substrate layer by said at least two compliant structures (108 and 109) located within the chamber; and the suspended element is configured to oscillate upon application of an actuating signal to at least one electrically conductive path, which runs across at least two of the compliant structures (108 and 109) and the suspended element; characterised in that: the suspended element comprises an insulating material and at least one patterned conductive layer providing the at least one electrically conductive path which runs across the suspended element, said suspended element having a total metal content less than 50% by weight. the suspended element comprises an insulating material and at least one patterned conductive layer providing the at least one electrically conductive path which runs across the suspended element, said suspended element having a total metal content less than 50% by weight.