keith johnston research group email: [email protected] synthesis and assembly of nanocrystals with...
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![Page 1: Keith Johnston Research Group Email: kpj@che.utexas.edu Synthesis and Assembly of Nanocrystals with Supercritical Fluids –Assembly on unpatterned and patterned](https://reader035.vdocument.in/reader035/viewer/2022062305/56649e7b5503460f94b7cda8/html5/thumbnails/1.jpg)
Keith Johnston Research GroupEmail: [email protected]
• 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. Nanocoatings1. Nanocoatings 2. Photonic crystals2. Photonic crystals 3. Inverse opals3. Inverse opals
4. Patterned structures4. Patterned structures 5. Microwires5. Microwires 6. Nanodevices6. Nanodevices
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A
B
• 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
Silicon PLE and PL (Ge also)
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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
)( CCsh
DS
dt
dm
D rug m o le c ule s
Surfac tant dif fus io n
N uc le i
Agglo m e ratio n
W ate r phaseO rganic phase
D iffus io n
Stabilizatio n o f drug par tic le s by surfac tants
Interface orients surfactantHigh surface area, wettability, dissol. rates and bioavailabilityHigh drug:surfactant ratios
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Destination of PhD Students
• DixonS. 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