| Jing Yong Ye | |
|
Associate Research Scientist office : 230 E.R.B. II |
Research Group : Ultrafast Science
Publications : Reference List (103 listed)
The general focus of my research is the development and
applications of ultrasensitive and ultrafast laser-based detection
strategies to the problems in condensed matter physics, biophysics
and analytical chemistry. Research Interests
My present research involves in use of novel materials for second-
and third-harmonic imaging of biological materials, novel techniques
for biological fluorescence lifetime imaging, and adaptive optics for
improved confocal imaging.
I also work on single molecule fluorescence imaging and spectroscopy.
Unlike the conventional experiment in condensed matter that measures
the average behavior of a huge number of molecules, single molecule
measurement reveals detailed properties of individual molecules free
from ensemble averaging. Many interesting phenomena unprecedentedly
become observable. Using this technique one can gain an in-depth view
of the nature of physical processes, chemical reactions and
biological systems. I investigated a dye molecule system with a
flexible molecular structure at a single-molecule level. The
site-dependent nonradiative process of the individual dye molecules
sensitively revealed the heterogeneous interactions between the dye
molecule and its local environment. For a biologically important
system, the interaction of a fluorescent nucleotide analogue with the
Klenow fragment of DNA polymerase I was visualized at a
single-molecule level. Furthermore, light-induced formation of
individual nucleotide-enzyme complexes was observed in real time and
in situ for the first time.
Femtosecond laser system provides us a powerful tool to investigate
ultrafast dynamics through direct observation. Combining the
ultrafast and ultrasensitive techniques, I succeeded in time-resolved
fluorescence measurements at a single-molecule level.
Enhancement of weak fluorescence is another interesting subject,
especially, for two-photon excited fluorescence, because two-photon
absorption cross section of most organic molecules is extremely
small. Using a one-dimensional photonic crystal, I observed a large
enhancement of two-photon excited fluorescence of 2-aminopurine doped
in a thin film as a defect layer in the photonic crystal. I further
applied a novel idea to enhance fluorescence imaging by a photonic
crystal and is applying for a patent for the method.
Besides light microscopy, atomic force microscopy (AFM) has a
dramatic impact on many fields owing to its high spatial resolution.
DNA is one of the most extensively studied molecules to understand
its structure and interactions with protein molecules. However, long
DNA molecules are subject to entanglements and aggregations, which
make measurements difficult or even impossible, because AFM is a
surface-based technique. The sample preparation, therefore, is
extremely important. I developed an effective approach to stretching
DNA molecules by spin-coating technique for sensitive AFM
measurement.
Moreover, I have also conducted researches on microscopic dynamics of
phase transition, ultrafast dynamics of TPM dyes, spectroscopic
properties and biological activities of nucleotide, interaction of
fluorescent analog with enzymes, and lasing without population
inversion, etc.