We use Atomic Force Microscopy (AFM) and other techniques to
investigate the structure, function and mechanism of biological
macromolecules and to characterize the nanoscale properties of
materials. AFM has a number of unique capabilities, and can
provide complementary information to that obtainable from other
macroscopic techniques. In addition to the imaging applications, the
AFM can be used to perform nanomanipulations, with the ability to
exert pico-newton forces and move objects with subnanometer
precisions. With these advantages AFM has significantly
impacted the fields of materials science, biology and other fields.
Current
Projects
Protein
unfolding induced by mechanical force.
Individual molecules of ubiquitin are unfolded/refolded through
modulation with mechanical forces to characterize the
unfolding/refolding pathways. We are doing the single molecule
measurements at different temperatures and in different solution
environments.
Characterization
of the physical properties of nanofibers.
The structural, mechanical, electrical and thermal properties of the
organic and protein fibers, produced by electric spinning, are
measured on individual fibers with sizes from tens of nanometers to
a several micrometers.
DNA
protein interactions
AFM imaging is used to investigate the mechanisms of the proteins
involved in repairing DNA double strand breaks via homologous
recombination.
Technical
Development
Efforts are being made to enhance the performance of the AFM by
fabricating better probes, implementing temperature capability and developing
data processing software.
Research
Funding
Our work is supported by NIH, NSF, Nanotechnology Institute
of Southeastern Pennsylvania, and Drexel University.
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