An apparatus and method for measuring augmented osmotic pressure in a reference cavity is provided, in which the device comprise a substrate frame (4) attached to a support structure (1) in which a plurality of transducer devices (2) are buried. An array of osmotic membranes (3) is integrated by the support structure and which acts to facilitate a trans-membrane pressure gradient as a function of the osmotic pressure change in a sealed cavity (7). The sealed cavity is formed by rigid substrate materials (5,6) in which the membranes, support structure and transducer devices only will be subject to induced stress in response to augmented osmotic pressure and thereby generate a pressure induced signal change observed from the transducer devices. The transducer devices may be arranged as piezoresistive elements, as micromechanical switches, as variable capacitive elements or as an optical light source and detector. The device can be used to monitor changes in osmotic pressure in response to a concentration change of a specified dissolved solute particle.