Implantable medical devices (IMDs) are an integral component for implementing next-generation therapies for more effective disease management and prevention. Today’s commercial IMDs such as the pacemaker, deep brain neurostimulators, and peripheral nerve stimulators are bulky and invasive due to the use of batteries and wired interfaces. Wireless powering and extensive miniaturization of these implants is crucial for making them minimally invasive and eliminating discomfort and the risk of infection for patients. Millimeter (mm) and sub-mm sized implants also have the potential to open up new applications in sensing, stimulation, and drug delivery. Providing sufficient power (100s of µW to a few mWs) to miniature implants located deep inside the body (> 10 cm) is a big technological challenge. In order to address this challenge, we have designed and optimized systems using ultrasound (US) for power transfer. Ultrasound offers wavelengths comparable to the size of the implant, enabling for: (i) focusing of energy at the implant, (ii) design of high efficiency mm- or sub-mm-sized harvesters, and (iii) low tissue attenuation, ultimately achieving high link efficiency and safe power transfer.
Our research on IMDs, starting back in 2012, covers the following broad topics (Figure 1): (1) optimized design and miniaturization of ultrasonically powered deep-tissue implants –, ; (2) robust, bi-directional data communication links using US/RF , , , -, ; (3) packaging and biocompatibility of IMDs; (4) end-to-end system design of IMDs for specific biomedical applications such as pressure sensing, electrical/optogenetic stimulation, drug delivery , , , , ; and (5) development of an ultrasonic transceiver for locating, powering and communicating with the IMDs .
- Prof. Pierre Khuri-Yakub, Electrical Engineering, Stanford University
- Prof. Richard Zare, Chemistry, Stanford University
- Prof. Stephen Felt, Comparative Medicine, Stanford University
- Prof. Justin Annes, Medicine (Endocrinology), Stanford University
- Dr. Matthew R. Myers, FDA
- Dr. Srikanth Vasudevan, FDA
. J. Charthad, T. C. Chang, Z. Liu, A. Sawaby, M. J. Weber, S. Baker, F. Gore, S. A. Felt, and A. Arbabian, "A mm-sized wireless implantable device for electrical stimulation of peripheral nerves," IEEE Trans. Biomed. Circuits Syst., vol. 12, no. 2, pp. 257-270, Apr. 2018.
. M. J. Weber, Y. Yoshihara, A. Sawaby, J. Charthad, T. C. Chang, and A. Arbabian, “A miniaturized single-transducer implantable pressure sensor with time-multiplexed ultrasonic data and power links,” IEEE J. Solid-State Circuits, vol. 53, no. 4, pp. 1089-1101, Apr. 2018.
. T. C. Chang, M. J. Weber, J. Charthad, S. Baltsavias, and A. Arbabian, “Scaling of ultrasound-powered receivers for sub-millimeter wireless implants,” IEEE BioMedical Circuits and Systems Conference (BioCAS), Turin, Italy, Oct. 19-21, 2017. 1st Place Best Paper Award
. M. L. Wang, T. C. Chang, T. Teisberg, M. J. Weber, J. Charthad, and A. Arbabian, “Closed-loop ultrasonic power and communication with multiple miniaturized active implantable medical devices,” 2017 IEEE International Ultrasonics Symposium (IUS), Washington, D.C., Sept 6-9, 2017.
. M. L. Wang and A. Arbabian “Exploiting spatial degrees of freedom for high data rate ultrasound communication with implantable devices,” Applied Physics Letters, vol. 111, no. 13, Sept. 2017.
. M. J. Weber, Y. Yoshihara, A. Sawaby, J. Charthad, T. C. Chang, R. Garland, and A. Arbabian, “A high-precision 36 mm3 programmable implantable pressure sensor with fully ultrasonic power-up and data link,” IEEE Symp. on VLSI Circuits, Kyoto, Japan, June 5-8, 2017, pp. 104-105.
. M. L Wang, T. C. Chang, J. Charthad, M. J. Weber, and A. Arbabian, “The power of Sound: miniaturized medical implants with ultrasonic links,” Proc. SPIE 10194, Micro- and Nanotechnology Sensors, Systems, and Applications IX, 101940Y, Anaheim, May 18, 2017.
. T. C. Chang, M. L. Wang, and A. Arbabian, “A 30.5 mm3 fully-packaged implantable device with duplex ultrasonic data and power links achieving 95 kbps with < 10-4 BER at 8.5 cm depth,” 2017 IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, February 5-9, 2017, pp. 460-461.
. A. Arbabian, T. C. Chang, M. L. Wang, J. Charthad, S. Baltsavias, M. Fallahpour, M. J. Weber, “Sound Technologies, Sound Bodies: medical implants with ultrasonic links,” IEEE Microwave Magazine, vol. 17, no. 12, pp. 39-54, Dec. 2016.
. T. C. Chang, M. J. Weber, M. L. Wang, J. Charthad, B. T. Khuri-Yakub and A. Arbabian, “Design of tunable ultrasonic receivers for efficient powering of implantable medical devices with reconfigurable power loads,” Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on, vol. 63, pp. 1554-1562, Oct. 2016.
. J. Charthad, S. Baltsavias, D. Samanta, T. C. Chang, M. J. Weber, N. Hosseini-Nassab, R. N. Zare, and A. Arbabian, “An ultrasonically powered implantable device for targeted drug delivery,” Engineering in Medicine and Biology Society (EMBC), 2016 38th Annual International Conference of the IEEE, Orlando, August 16-20, 2016.
. M. J. Weber, A. Bhat, T. C. Chang, J. Charthad, and A. Arbabian, “A miniaturized ultrasonically powered programmable optogenetic implant stimulator system,” in IEEE Biomed. Wireless Technol., Networks, Sens. Syst. Top. Conf., Austin, TX, USA, Jan. 2016. 1st Place Best Paper Award
. T. C. Chang, M. J. Weber, J. Charthad, A. Nikoozadeh, B. T. Khuri-Yakub, and A. Arbabian, “Design of high-efficiency miniaturized ultrasonic receivers for powering medical implants with reconfigurable power levels,” IEEE Ultrasonics Symposium, Taipei, Taiwan, Oct. 21-24, 2015. Nominated for Best Student Paper Award
. J. Charthad, M.J. Weber, T. C. Chang, and A. Arbabian, “A mm-sized implantable medical device (IMD) with ultrasonic power transfer and a hybrid bi-directional data link,” IEEE Journal of Solid-State Circuits, vol. 50, no. 8, pp. 1741-1753, Aug. 2015.
. J. Charthad, M. J. Weber, T. C. Chang, M. Saadat, and A. Arbabian, “A mm-sized implantable device with ultrasonic energy transfer and RF data uplink for high-power applications,” 2014 IEEE Proceedings of the Custom Integrated Circuits Conference (CICC), September 2014.