Pressure and temperature dual-parameter fiber sensing for intracranial pressure monitoring applications

Intracranial pressure monitoring is critically important for the diagnosis and management of patients in neurocritical care. To address the limitations of existing invasive sensors, including infection risks, high cost, and susceptibility to electromagnetic interference, as well as the insufficient accuracy of non-invasive sensors, this work presents the design and fabrication of a miniaturized optical fiber sensor based on a polydimethylsiloxane membrane Fabry-Perot interferometer and a fiber Bragg grating for simultaneous temperature and pressure monitoring. Experimental results demonstrate that within the clinically critical pressure range of 7-70 cmH₂O, the sensor exhibits high linearity (R² > 0.99), high pressure sensitivity (0.20 μm/cmH₂O), and high accuracy (single-measurement error ≤ 2.1 cmH₂O). In the physiological temperature range of 35-41°C, its temperature measurement sensitivity reaches 8 pm/°C. The Fabry-Perot interferometer and fiber Bragg grating signals operate without mutual interference, enabling decoupled measurement of temperature and pressure. Repeatability tests conducted over 21 days and extended stability tests confirm the sensor's exceptional long-term stability and reproducibility. Compared with conventional sensors based on silicon or metal diaphragms, the PDMS membrane employed in our design can be fabricated using a straightforward spin-coating process, eliminating the need for complex micromachining. This approach not only significantly reduces the sensor probe's fabrication complexity and cost but also, owing to the high elasticity of polydimethylsiloxane, yields enhanced pressure sensitivity. This research provides a highly promising technological solution for high-performance, cost-effective, and accurate intracranial pressure monitoring.