Fig. 3.

a) Diagram of sensor components of the touch-mode capacitive pressure sensor device (adapted from Ref. [87] under Creative Commons Attribution (CC BY) license). b) The structure of the combined cross-beam membrane and peninsula of a novel piezoresistive pressure sensor (Redrawn from Ref. [88]). c) Three-dimensional (3D) illustration of a micro-scale intraocular pressure sensor with nanotouch amplification and the principles of its operation, its location in the anterior chamber and experimentally determined spectra from the sensor in comparison with theoretically predicted spectra showing a high correspondence between sensor measurements (vertical axis) and digital pressure gauge readings (horizontal axis) (adapted from Refs. [88,89] under a Creative Commons Attribution 4.0 International License). d) The structure of the catheter tip with an integrated pressure sensor and electronics for measuring bladder pressure (Adapted by permission from Springer: Nature Science [90] © 2008).