Lasers and Optical Characterization Lab

Ed Van Keuren, Changbao Ma, Kristen Perlot, David Littlejohn, John Menzel, Johnny Rogers, Mike Lavoie, Jonathan Flyer

GAEL: Mak Paranjape, John Currie, Ali Leeds, Drew Monica

SAIC: Tom Schneider, Robb White

BASF: Wolfgang Schrof

Dept. of Chemistry: Jen Swift

ChemImage: Pat Treado, Matt Nelson

• Nanoparticle synthesis and characterization

• Imaging using molecular probes

• MEMS/MOEMS

Nanoparticle synthesis and characterization

• Aggregation/crystallization of organic nanoparticles in binary solvents

• Fluorescence correlation spectroscopy

• Nanocomposite OLEDs

Nanoparticle nucleation

Solvent shifting:• Nucleation induced by exchange of solvent

with miscible non-solvent (micronization, reprecipitation, drowning out crystallization)

• Rapid (injection) or slow (ternary phase transition)

Nanoparticle nucleation

Solute

Organic solvent

WaterIII

I: Clear solution

II: Bulk precipitate

Solution

(water- miscible

solvent)

Water

Nanoparticle nucleation

How do single molecules come together in solution to form nanoparticles?

• Transition from distribution of unstable clusters to nucleation sites

• Cluster size distribution • Cluster lifetimes

Spectrally selective FCS

Fluorescence Correlation Spectroscopy (FCS)

Minute sampling volume defined by confocal optics

Low concentration – 10-7 to 10-12 M

Temporal variation in fluorescence emission due to number fluctuations, changes in chemical species

Autocorrelation function of fluorescence can yield diffusion coefficients, reaction rates

Fluctuations from changing species

Number fluctuations from particle diffusion

Spectrally selective FCS

• Perylene: long wavelength bands in nanocrystals diffusion of the aggregates only.

• MgPC: fluorescence quenching (650 - 800 nm) in nanoparticles will allow diffusion coefficients of single molecular species to be isolated.

Polymer nanoparticles

Monomer nanoparticles formed by rapid injection into nonsolvent, which induces aggregation, followed by initiation of free radical polymerization.

Imaging using molecular probes

• Three dimensional thermal imaging

• 2 photon FRAP

• Pattern photobleaching

Thermal imaging in tissue

• 3-d fluorescence imaging + temperature dependent dye measurement of temperature profiles near MEMS heaters

Pattern photobleaching

Pattern created using two photon photobleaching

Can follow micro-deformations in polymer films, for example, water absorption

MEMS/MOEMS

• Detection of biomarkers by competitive binding in microchannels

• 2-d protein separations chip

• Thermo-optic waveguide switches

Optical biomarker detection with competitive binding

• Development of a MEMS device containing both optical waveguides and microfluidic channels

• Single mask• Competitive binding of

analyte with tagged receptors for fluorescence detection

-

-

-

glucose

Con A

fluorescentlytagged dextran

Optical biomarker detection with competitive binding

Optical biomarker detection with competitive binding

Optical biomarker detection with competitive binding