Structural and Dynamic Heterogeneity of Nanomaterials and Biomolecules Probed by Ensemble and
Single Molecule Spectroscopy
Colin D. Heyes, Department of Chemistry and Biochemistry, University of Arkansas
Relating the structure, dynamics and function of both nanomaterials and biomolecules is a highly
complex endeavor, largely due to both species showing static and dynamic heterogeneity. Recently, a
major thrust has been to combine these two fields to open up new frontiers in bionano research.
Combining them opens up new possibilities for biomedical, renewable energy and optoelectronic
advances if we are able to gain a better understanding of their structure-dynamics-function
relationships.
In the first part of my talk, I will describe our recent research in developing fluorescent nanoparticles for
quantitative bioimaging applications. Due to the high surface-to-volume ratio of nanoparticles, the
fluorescence properties of colloidal quantum dots (QDs) are strongly affected by the various interfaces
present. Simple core-only QDs have an inorganic-organic surface-ligand interface, while core-shell (or
core-multishell) quantum dots have, in addition, inorganic-inorganic core-shell interfaces. We
systematically tune these interfaces and determine how they affect the optical and structural properties
at the ensemble and single particle level. We also take advantage of the photoactive nature of these
nanomaterials towards performing photocatalytic crosslinking of ligands which improves aqueous
colloidal stability while limiting their size.
In the second part of this talk, I will discuss single molecule FRET approaches to better understand how
protein dynamics underlie protein interactions and targeting. Specifically, we are interested in
deciphering how the hydrophobic light-harvesting chlorophyll-binding protein (LHCP) that underlies light
harvesting and photosynthesis in plants is transported and inserted into the thylakoid membrane. This
process involves multiple protein interactions that must occur in a specific order to enable efficient
unidirectional targeting. We propose a narrowing of the energy landscape may be responsible for this
unidirectional targeting mechanism.
Finally, I will discuss future directions and potential challenges in combining nanomaterials and
biomoelcules for more advanced and quantitative applications.