Data and Time March 9, 2010, 2:55-4:15 PM
Location Sanford Fleming Building (SF), Room B560
Host Leon Yuan

Nanostructure Based Label-Free Biosensing

Xihua Wang

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Photonics)


Fluorescence-label based sensing methods show great success in DNA and protein detection. However, labeling a biomolecule can dramatically change its binding properties, which revents people to investigate the true nature of molecular biology. Thus the label-free biosensing becomes an attractive research by this urgent need. Nanotechnology brings new tools to improve the device performance for electrical and optical detection of biomolecules. Optical sensing methods, such as ring resonator, surface plasma resonance, and nanocavity, have been successfully applied in label-free biosensing. Sensitive electrical detection using nanoscale field-effect devices has also been demonstrated. These nano-electronic devices have large surface-to-volume ratio compared to conventional large scale field-effect sensors, and thus have greater sensitivity to bimolecules bound to the surface. In our research, we use a ‘top-down’ fabrication method to develop nano-electronic devices with conduction channel width of 50nm. Highly sensitive detection of various chemical and biological species has been demonstrated by using this platform.


Xihua Wang received his bachelor's degree in physics in 2003 from Peking University. Then he started his graduate study in the physics department at Boston University. His Ph.D. research focused on nano-electronic and nano-optic biosensing, and he defended his thesis in the end of 2008. He joined Prof. Sargent’s group at University of Toronto as postdoctoral fellow in 2009, and is currently working on colloidal quantum dot photovoltaics.