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External ultrasound can generate microampere direct currents in vivo from implanted piezoelectric materials
Author(s) -
Cochran George V. B.,
Kadaba Murali P.,
Palmieri Vincent R.
Publication year - 1988
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100060119
Subject(s) - piezoelectricity , materials science , ultrasonic sensor , transducer , ultrasound , ultrasound energy , biomedical engineering , ceramic , electrode , external fixation , nonunion , acoustics , composite material , surgery , medicine , chemistry , physics , prosthesis
Under development is an internal fixation plate that incorporates a piezoelectric element to generate current when excited mechanically by either weight bearing or external application of ultrasound. The intent is to deliver this current to electrodes at a fracture or osteotomy site to aid in prevention or treatment of nonunion. The present study examines quantitatively the ability of external ultrasound to generate current from small piezoelectric ceramic elements implanted in tissue. An ultrasonic transducer (2.25 MHz, 10–20 V input, <10 mW/cm 2 output) was employed to excite small test coupons of a piezoelectric ceramic in vitro and in vivo with various materials, including water, PVC gel, cortical bone, and living soft tissues, interposed. In all instances, it was possible to generate currents of up to 20 μA after rectification; currents up to 1 mA were achieved in some cases. The work indicates that external ultrasonic energy could effectively power small internal devices designed to stimulate bone healing, without the need for implanted batteries or percutaneous leads.