Micro sensors to monitor blood pressure
(a) An exploded view of the double layer planar micro inductors, (b) A summary of the fabrication steps: (1) Oxide deposition and UV Lithography, (2) E-beam evaporation and lift-off. (3) SiO2 deposition and etching. (4) Steps 1–2 repeated for the second inductor layer, (c) A scanning electron micrograph of the resulting coil.
Hypertension, if left untreated, can lead to a number of health problems including strokes, heart failure and kidney failure. Regular monitoring of blood pressure is currently inefficient and is not performed as regularly as necessary to monitor and mitigate these serious health concerns.
Led by Dr. Tuncay Alan, researchers from Monash University are developing a highly sensitive, implantable blood pressure sensor. These micro-sensors could be implanted into patients suffering high blood pressure to better monitor levels. This would allow continuous and routine blood pressure measurement and readings would then be communicated wirelessly to a hip-held alert unit. The results could then lead to earlier diagnoses of related diseases, complications and more efficient treatment.
The devices being investigated by Dr Tuncay Alan and Associate Professor Neild in the Laboratory for Microsystems, are inductor sensors which are far more sensitive when downscaled than other sensors which have previously been researched. The team have developed a model which uses two planar spirals separated by an insulating layer, and have fabricated double layered microplanar coils at MCN. The opposing magnetic fields between pairs of these coils create a high sensitivity to relative displacement which can be linked to pressure. Results so far show that device dimensions could be shrunk for further improvements on resolution. Overall results indicate that inductive sensing has a good potential for micro scale sensing applications. Collaborators are currently investigating the circuitry necessary for the sensor and the fabrication of a complete system.
You can read more about this project in Nanoscale displacement sensing using microfabricated variable inductance planar coils, published in Applied Physics Letters.