An inductively powered implantable blood flow sensor microsystem for vascular grafts.
Monitoring blood flow rate inside prosthetic vascular grafts enables an early detection of the graft degradation, followed by the timely intervention and prevention of the graft failure. This paper presents an inductively powered implantable blood flow sensor microsystem with bidirectional telemetry. The microsystem integrates silicon nanowire (SiNW) sensors with tunable piezoresistivity, an ultralow-power application-specific integrated circuit (ASIC), and two miniature coils that are coupled with a larger coil in an external monitoring unit to form a passive wireless link. Operating at 13.56-MHz carrier frequency, the implantable microsystem receives power and command from the external unit and backscatters digitized sensor readout through the coupling coils. The ASIC fabricated in 0.18-μm CMOS process occupies an active area of 1.5 × 1.78 mm (2) and consumes 21.6 μW only. The sensors based on the SiNW and diaphragm structure provide a gauge factor higher than 300 when a small negative tuning voltage (-0.5-0 V) is applied. The measured performance of the pressure sensor and ASIC has demonstrated 0.176 mmHg/√Hz sensing resolution.
Institute of Microelectronics, Agency for Science, Technology and Research, Singapore. cheongjh@ime.a-star.edu.sg
Jia Hao
JH
Cheong
Simon Sheung Yan
SS
Ng
Xin
X
Liu
Rui-Feng
RF
Xue
Huey Jen
HJ
Lim
Pradeep Basappa
PB
Khannur
Kok Lim
KL
Chan
Andreas Astuti
AA
Lee
Kai
K
Kang
Li Shiah
LS
Lim
Cairan
C
He
Pushpapraj
P
Singh
Woo-Tae
WT
Park
Minkyu
M
Je
D001698:Biomedical Engineering / Q000295:instrumentation; D001807:Blood Vessel Prosthesis; D004867:Equipment Design; D008962:Models, Theoretical; D053770:Nanowires; D012039:Regional Blood Flow; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D012825:Silicon; D013686:Telemetry / Q000295:instrumentation*; D059015:Wireless Technology / Q000295:instrumentation*
D012825:Silicon