Welcome to the Schwartz Research Group!
The Schwartz Research Group at CU-Boulder is broadly interested in interfacial science. We are leading the way in the development of liquid crystal sensors, chemically-modified catalysts, and single-molecule imaging methods.
- Dynamics of (bio)molecules at interfaces
- Molecular targeting (biosensing)
- Liquid crystal anchoring and alignment
- (Catalytic) surface modification
Instruments and Methods
- Single-molecule total internal reflection fluorescence microscopy
- Polarized light microscopy
- Surface modification (thin films and self-assembled monolayers)
- Surface characterization (contact angle goniometry, FTIR, ellipsometry)
- Atomic force microscopy
- Spectroscopy (circular dichroism, UV-vis, fluorescence)
- Numerical simulations and machine-learning
- Langmuir trough
- Brewster angle microscopy
Advanced Functional Materials:
Visualizing Liposome Fusion
Using Liquid Crystals
10.1002/adfm.201303885 Understanding how to control liposome fusion
has significant value toward understanding biological systems and
advancing technologies such as drug delivery strategies, synthetic gene
transfer agents, and bio-sensing applications. In collaboration with
the Goodwin Research Group we have developed an approach for monitoring
receptor-mediated fusion that exploits the advantageous properties of
liquid crystals (e.g. optical anisotropy, long range orientational
order, and sensitivity to external stimuli). Oligonucleotides were
anchored within the bilayer of dispersed liposomes and at a PEG-lipid
laden aqueous/LC interface. When these oligonucleotides were
complementary, DNA hybridization occurred, promoting lipid mixing with
the LC interface and depositing lipids to the interface at a high
enough density to initiate LC re-orientation to a homeotropic state.
The applicability of this approach as a bio-sensing strategy was
demonstrated by incorporating aptamer–ligand binding into the detection
scheme to modulate fusogenic activity. Future work in this area will
involve optimizing conditions for advanced bio-sensing (e.g. detection
in complex media, improved sensitivity) and exploiting this system to
study naturally occurring biological receptors (e.g. SNAREs).
JACS Spotlight: Surface-Bound Polymers Wriggle and Hop
10.1021/ja407396v It is well known that polymers interact with
surfaces, but the mystery lies in how exactly they move once attached.
Polymers have been commonly assumed to move about the two- dimensional
plane of the surface to which they are adsorbed, but a new study
suggests their behavior is much more dynamic. Michael Skaug, Joshua
Mabry, and Daniel Schwartz use single-molecule tracking experiments to
reveal that the widely used polymer, poly- (ethylene glycol) (PEG),
wriggles and hops along hydrophobic surfaces. The team uses total
internal reflection fluorescence microscopy to observe the movements of
individual surface-adsorbed PEG molecules and find mobility is
dependent on molecular weight. The results suggest that the
interactions between surfaces and molecules in bulk solution may be
stronger than previously believed, which could help explain certain
previously puzzling phenomena, such as anomalously slow removal of
surface-adsorbed polymers and the influence of highly attractive
surfaces on the diffusion of polymers in solution. But it remains an
open question whether this desorption-mediated mechanism observed for
PEG can be assumed for other classes of polymers.
Reprinted (adapted) with permission from Spotlights on Recent JACS Publications. Christine Herman. Journal of the American Chemical Society 2013 135 (49), 18237-18237. Copyright (2013) American Chemical Society.