Bistable magnetic microwire for contactless sensor of intracranial pressure

Abstract

The given paper presents one new opportunity of glass-coated microwires for biomedical applications, especially the possibility of pressure measuring inside a human cranium. The application allows noninvasive and contactless sensing of the intracranial pressure (ICP) using FeSiBP glass-coated microwire for a sensor in a model of skull. First, the measurement of the mechanical dependence of the switching time dt on the microwire shows almost linear progression. In this case the middle tensile sensibility ST (slope value) of microwire is 1.84 μs/MPa. The studied microwire, implanted in the skull as a sensor, could measure intracranial parameters simultaneously at any time, only by attaching the probe from the outside of the head. The experimental measurements have been carried out on the skull model with the water balloon, which has similar properties and Young's modulus of cerebral membrane - dura. The measurements, in the range of values corresponding to normal intracranial pressure show, that the switching time dt monotonously increases with increasing hydrostatic pressure in the water balloon, where the average tensile sensibility ST is about 38 ns/Pa. The high theoretical sensibility about 0.3 Pa can be achieved. This approach makes this technology very interesting for the practical application.