New manufacturing technique could transform implantable medical devices
Researchers have demonstrated a way to manufacture complex circuits on stretchy materials using liquid metal, enabling devices like cochlear implants to be made faster and more precisely. The technique could streamline production of neural interfaces and sensor arrays, opening commercial opportunities in medical device manufacturing and brain-computer interfaces.
Originaltitel: Liquid Metal-Based High-Density Interconnect Technology for Stretchable Printed Circuits
<p>High-density interconnect (HDI) technology for liquid metal (LM)-based stretchable printed circuit boards is crucial for expanding their applicability. HDI technology provides high-resolution multilayer circuits with a high density of components, as required for next generation of neuroprobes and ultrasonic and sensor arrays. This study presents a HDI technique utilizing laser engraved micro grooves in silicone with a protective lift-off mask of polyvinyl alcohol (PVA) and subsequent microscale LM particle spray deposition. This approach achieves high-resolution LM patterns and enables multilayer connectivity and high-density integration of components simultaneously, that is, realizing HDI technology. It is demonstrated using a stretchable 0201 LED display with a density of six leads per mm2 and a cochlear implant (CI) electrode array. The demonstrated manufacturing of the CI has the potential to enable fully automated printed circuit board manufacturing of such implants with increased precision and throughput. Implants in guinea pigs show that the CI is capable of activating the auditory neuron with electrical auditory brainstem response (eABR) and electrical compound action potential (eCAP) of high quality. Moreover, the U-shaped cross section of the LM interconnects provides a higher mechanical shock resistance of the circuit than that of normal rectangular cross sections. A liquid metal based high-density interconnect technology that is capable of fabricating high resolution circuits and integrating electronic high-density components in multilayer stretchable system, which are demonstrated by a stretchable high-density integrated LEDs display and an eight-electroe array of a cochlear implant.image</p>