Associate Professor of Chemical Engineering

Research Areas

Multifunctional Soft Electronics

Research Interests

BRAIN INJECTABLE SENSOR AND ELECTRONICS
We’ve developed new bio-integrated electronic system. To stimulate specific neural activity, optogenetics provides a unique opportunity. It can specifically excite or inhibit a single scale of genetically modified neuron with light. Conventional methods such as optical fiber and laser tool are really bulky and inconvenient. In our laboratory, the new class of fabrication method for the wireless neural modulation by optoelectronic devices has been investigated. Our novel devices utilize flexible substrates to carry wirelessly powered microscale, inorganic light-emitting diodes (ｵ-ILEDs) and multimodal sensors such as thermal, optical and electrophysiological sensors inside the brain. The implementation of these devices allows for chronic, wireless optogenetic manipulation of neural circuitry in animals experiencing behaviors such as social interaction, home cage, and other complex natural environments.

ULTRASENSITIVE MECHANO- NANOSCALE CRACK BASED SENSOR INSPIRED BY SPIDER’S SENSORY ORGAN
We developed highly sensitive mechano-sensors, nanoscale crack junction based sensors inspired from the geometry of spider’s slit organ. The sensors show extremely high sensitivity in strain (gauge factor over 16,000 at 0-2% strain range), vibration (approximately 10 nm amplitude detection capability), and pressure. The device is also reversible and mechanically flexible, and thus, it can be easily mounted on human skin as skin electronics. The system is applicable for highly selective speech pattern recognition and the detection of physiological signals from humans.

Selected Publications

1. “Nanoscale dewetting based direct interconnection of microelectronics for a deterministic assembly of transfer printing” Adv. Mater. 32 (21) 1908422 (2020)

2. “Injectable biomedical electronics for sensing and stimulating internal body organs” Adv. Mater. 32 (16) 1907478 (2020)

3. “Dramatically Enhanced Mechanosensitivity and Signal-to-Noise-Ratio on Nanoscale Crack based Sensors: Effect of Depth” Adv. Mater. 28 (37) 8130-8137 (2016)

4. “Ultransensitive mechanical crack-based sensor inspired by the spider sensory system” Nature 516, 222 (2014)

5. “Injectable Cellular Scale Optoelectronics with Applications for Wireless Optogenetics” Science 340, 211 (2013)

Professional Experience

– 서울대학교 기계항공우주공학부, 박사후 연구원, 2009.02~2009.5
– 일리노이대 (University of Illinois at Urbana-Champaign, Materials and Science Engineering), 박사후 연구원, 2009.06~2013.01