Inductively coupled microfluidic pressure meter for in vivo monitoring of cerebrospinal fluid shunt function.
A microfluidic pressure sensor with inductively coupled, wireless readout capability has been developed for integration into cerebrospinal fluid shunt valve implants. The sensor consists of a deformable PDMS film that is bonded over a microfluidic reservoir, forming a fluidic capacitor. Deflection of the capacitor membrane is detected remotely through a shift in the resonance frequency of a micro-fabricated LC circuit. Sensors were fabricated by a combination of conventional MEMS technologies and rapid soft lithography. A direct pattern transfer technique was used to pattern the deformable PDMS film with a metal coating for the capacitive readout. The mechanical response of the fluidic capacitor was characterized by measuring the deflection of the PDMS film using an extrinsic Fabry-Perot interferometer (EFPI), and wireless sensing was demonstrated by the shift in resonance frequency of the sensor via an inductively coupled antenna. The sensor transduces pressure into a change in resonant frequency with sensitivity > 3.4 ppm Pa⁻¹ and responsivity 4.6 kHz Pa⁻¹, over a dynamic range of 0~3 kPa.
Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA.
S-H
SH
Song
G T
GT
Gillies
M R
MR
Begley
M
M
Utz
W C
WC
Broaddus
D002557:Cerebrospinal Fluid Shunts / Q000379:methods*; D004129:Dimethylpolysiloxanes; D004867:Equipment Design; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods*; D011312:Pressure; D014160:Transducers, Pressure; D059015:Wireless Technology / Q000295:instrumentation
D004129:Dimethylpolysiloxanes; C013830:baysilon