Keith Johnston Research Group Email: [e-mail]

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Keith Johnston Research GroupEmail
kpj_at_che.utexas.edu

• Synthesis and Assembly of Nanocrystals with
  Supercritical Fluids
• Assembly on unpatterned and patterned substrates
• Si and Ge nanocrystals, nanowires (high T)
• Controlled release of nanoparticle
  pharmaceuticals (oral, depot, pulmonary)
• Poorly water soluble drugs
• Peptides and proteins- (stability and release)

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Fast Nanocrystal Evaporation w/o Dewetting
Lin et al. J. Phys. Chem. B, 2001.
Ag/FOMA/CO2 Control supersaturation during
evaporation of liq. CO2 Shah et al. 2003
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Nanocrystal Assembly on Surfaces
1. Nanocoatings
2. Photonic crystals
3. Inverse opals
4. Patterned structures
5. Microwires
6. Nanodevices
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Silicon PLE and PL (Ge also)

• Significant blue-shift compared to bulk silicon
  band gap
• Discrete features in PLE spectra Room T quantum
  yield of 23
• Size dependent luminescence
• UV, green light- displays/sensors
• Future- control size, yield, contamination,
  measure optoelectronic properties

A
B
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High Dissolution Rates for Poorly Water Soluble
Drug Nanoparticles

• Solution based nucleation
• Antisolvent (2 processes)
• Evaporation
• freezing (2 processes)
• Control nucleation, growth and stabilization
• Animal tests- bioavailability

2 nm danazol domains mixed with PVP (spray
freezing)
www.bioaqueous.com (Dow Chemical)
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Nanostructured particles by rapid nucleation and
surfactant stabilization
Interface orients surfactant High surface area,
wettability, dissol. rates and bioavailability Hig
h drugsurfactant ratios
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Destination of PhD Students

• Dixon S. Dakota S. Mines
• Gupta Auburn
• Balbuena U. S. Carol.
• Luna-Barcenas CINVESTAV Res. Inst.
• Meredith Ga. Tech.
• Yates U. Rochester
• Da Rocha Wayne State U.
• Lee U. S. California

• McFann Unilever
• Condo 3M
• Harrison TI
• Mawson Union Carbide
• Li Cardinal Health
• Young Dow (Pharma)
• Psathas Schering-Plough
• Rogers Dow (Pharma)
• Sirard Lam Research