On the feasibility of a liquid crystal polymer pressure sensor for intracranial pressure measurement

Intracranial pressure (ICP) monitoring is crucial in determining the appropriate treatment in traumatic brain injury. Minimally invasive approaches to monitor ICP are subject to ongoing research because they are expected to reduce infections and complications associated with conventional devices. This study aims to develop a wireless ICP monitoring device that is biocompatible, miniature and implantable. Liquid crystal polymer (LCP) was selected to be the main material for the device fabrication. This study considers the design, fabrication and testing of the sensing unit of the proposed wireless ICP monitoring device. A piezoresistive pressure sensor was designed to respond to 0-50 mm Hg applied pressure and fabricated on LCP by standard microelectromechanical systems (MEMS) procedures. The fabricated LCP pressure sensor was studied in a moist environment by means of a hydrostatic pressure test. The results showed a relative change in voltage and pressure from which the sensor's sensitivity was deduced. This was a proof-of-concept study and based on the results of this study, a number of recommendations for improving the considered sensor performance were made. The limitations are discussed, and future design modifications are proposed that should lead to a complete LCP package with an improved performance for wireless, minimally invasive ICP monitoring.