For detailed information of our group's research interest, please refer to "Publications" section.
1. High
Performance Bio-integrated Devices for Clinical Applications
Our research aims
to develop technologies for high performance flexible and stretchable
electronic devices using high quality single crystal inorganic materials that
enable a new generation of implantable biomedical systems with novel
capabilities and increased performance. Implantable systems for brain-machine
interfaces and clinical cardiology represent two examples where the devices
that we have achieved offer vast improvement in measurement resolution,
recording speeds, sensitivity and signal quality, compared to existing
technologies. The capabilities, in fact, approach those of devices based on
conventional, wafer-based technologies but without the associated constraints
for use on in-vitro, planar tissue slices or in destructive modes that involve
penetrating pins into target tissues. Our technologies provide soft,
conformable devices that can establish intimate contacts to curvilinear
surfaces of brain and heart, without any damage or alteration in the tissue,
with important, clinically relevant modes of use. The key idea behind these
high performance flexible and stretchable electronic systems is the use of
conventional high quality inorganic materials in structured nanomembranes
designed to reduce bending-induced strains by several orders of magnitude.
Direct transfer printing of these structures provides an effective assembly and
integration strategy; neutral mechanical plane designs with mechanically
optimized noncoplanar serpentine layouts, and elastomeric substrates, yield the
desired stretchable/flexible forms needed for conformal integration on soft,
three dimensional tissues.
In the area of
clinical device research, we have collaborated closely with practicing
cardiologists to demonstrate our devices for recording cardiac
electrophysiology, in-vivo, using a swine model with high spatial and temporal
resolution. Constant current source and multiplexing circuits using silicon
transistors were built on flexible plastic substrates for high resolution
in-situ electrocardiography mapping array. We also applied stretchable
electronics technology to create advanced, multifunctional balloon catheters
that incorporate simultaneous electrical, pressure, temperature and blood flow
sensors. The catheters also included the capability to electrically pace and ablate
the heart tissues and LEDs to trigger future light-modulated drugs. These
advanced diagnostic and therapeutic tools improve current surgical capabilities
for treating arrhythmias and other cardiac diseases, due to their minimally
invasive modes, and rapid capabilities for obtaining high resolution potential
maps of large area cardiac surfaces and other physiological information
simultaneously without manual repositioning of electrodes.
High resolution
and real time interface with the brain will enable advanced micro-seizure
detection and epilepsy prediction that current clinical technology cannot
provide as well as high-performance brain computer interface technology for
neuro-prosthetic systems. In the area of clinical medicine, the technology that
we have developed is already being used for research in feline animal models of
epilepsy to understand the brain network activity that initiates, sustains and
terminates seizures. Improved conformal contacts between electrodes and brain
tissues enable high quality electrocorticography recording.
These achievements
were published in high impact journals and honored through several awards. In
the future, we plan to continue to collaborate with both clinicians and
biomedical device companies to help patients and advance basic research though
commercializing these technologies. Detailed images are provided in the main
page of this website.
2. Low Cost Energy Harvesting and Lighting Devices
Our second
research goal is to create the low cost energy harvesting and light emitting
devices using nanostructured electronic materials and unconventional processing
technologies to provide electricity for all people in the world, especially for
developing world. Low cost energy will power the water filtration system to provide
clean water for people who suffer from contaminated water. High efficiency and
low cost lighting system will provide light to read for all children in the
world with minimum energy requirement.