Chi Hwan Lee receives grant to support development of flexible vertical silicon probes

Purdue Professor Chi Hwan Lee
Chi Hwan Lee
Chi Hwan Lee, an assistant professor of biomedical engineering and mechanical engineering, has received a $110,000 grant, renewable on an annual basis, from the U.S. Air Force Office of Scientific Research. The grant supports his work to develop flexible probes for use in neural sensing and interfacing on the brain. The probes consist of vertically ordered semiconducting silicon arrays that can transmit electrical signals with high signal-to-noise ratio.

Vertical silicon probes currently in use are typically built on rigid wafer-based substrates that are a structural mismatch with the soft, curvilinear surface of tissues such as the brain. To fit snugly on the curved surface of tissues, the probes are currently manufactured in a structure of staggered lengths to create an array with graded access. This approach results in low-fidelity mechanical/electrical coupling and an increased potential for damage to tissues, especially when implanted for a long period of time. The grant will further Lee’s work developing vertical silicon probes on a flexible, stretchable, and bio-compatible substrate that will allow flexible access into tissues to improve mechanical/electrical coupling in a minimally noninvasive manner.

“We strongly believe that these studies will open up new possibilities for highly efficient novel interfaces in the bio/nano/3D electronics for electrical recording and stimulation at multiscale in a minimally non-invasive fashion, which cannot be achievable by exploiting existing sensing technologies,” Lee says.

Lee is collaborating on the research with Dong Rip Kim, an assistant professor of mechanical engineering at Hanyang University in South Korea. Kim’s group developed a technique to define nanoscale 3D textures on the surface of silicon probes, which can significantly improve the contact quality between silicon probes and tissues. Kim and Lee have collaborated for a decade and published more than 14 co-authored journal papers. 

Lee’s research group also focuses on diverse types of wearable biomedical devices for many promising applications such as intracellular monitoring nano-systems, personalized rehabilitation and smart healthcare systems, and therapeutic electronic contact lenses.