Bioresorbable Conductive Wire with Minimal Metal Content

Abstract

The emergence of transient electronics has created the need for bioresorbable conductive wires for signal and energy transfer. We present a fully bioresorbable wire design where the conductivity is provided by only a few micrometers thick electron-beam evaporated magnesium layer on the surface of a polymer fiber. The structure is electrically insulated with an extrusion coated polymer sheath, which simultaneously serves as a water barrier for the dissolvable magnesium conductor. The resistance of the wires was approximately 1 Ω cm–1 and their functional lifetime in buffer solution was more than 1 week. These properties could be modified by using different conductor materials and film thicknesses. Furthermore, the flexibility of the wires enabled the fabrication of planar radio frequency (RF) coils, which were wirelessly measured. Such coils have the potential to be used as wireless sensors. The wire design provides a basis for bioresorbable wires in applications where only a minimal amount of metal is desired, for example, to avoid toxicity.

Materials and Orthopedic Applications for Bioresorbable Inductively Coupled Resonance Sensors

“…Physical vapor deposition (PVD) methods are attractive for fabricating conductors because they can be utilized without transfer printing, and the techniques can be readily applied onto many types of substrates. In this study, e-beam evaporation was used for Mg deposition, as it is known to be a capable method for producing Mg films at the micrometer scale. − On the contrary, the Zn films were magnetron sputtered because the high vapor pressure of Zn results easily in undesirable wall deposits in evaporation systems . Evaporated Mg (7.5 μm) and sputtered Zn (∼4 μm) films were first deposited on bioresorbable PDTEC substrates to study the morphology of the conductors.…”

“…The reading distance of all LC circuit-based sensors was investigated by using the same measurement setup, which included a double-turn square reader coil (diameter about 20 mm) on a printed circuit board (PCB). 45 The reading distance was stepwise increased by adding 1 mm glass slides between the reader coil and the sensor. After each 1 mm increment, the real part of the impedance of the reader coil was measured with an impedance analyzer (Agilent 4396B).…”

Recent Advances of Energy Solutions for Implantable Bioelectronics

“…the device must contain an energy source and conducting wires that transfer the signal and energy are also essential. [ 36,37 ] In this regard, implantable electronics can be divided into two categories, active and passive, relying on whether they have an energy source or not.…”