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Quantum Dots   

Patent Abstracts

From 08/18/2014 through 1/7/2011

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Patents with Abstracts

8,193,010 
Uniform transfer of luminescent quantum dots onto a substrate
 
Gopal et al of the University of Texas, Texas, developed a method of uniformly transferring luminescent quantum dots onto a substrate, comprising: a) preparing a colloidal suspension of luminescent quantum dots in a hydrophobic solvent, wherein the density of the hydrophobic solvent is from 0.67 g/cm.sup.3 to 0.96 g/cm.sup.3; b) dispensing the suspension onto a convex aqueous surface; c) allowing the hydrophobic solvent to evaporate; d) contacting the film of luminescent quantum dots with a hydrophobic stamp; and e) depositing the film of luminescent quantum dots onto a substrate with the hydrophobic stamp is described herein. (RDC 6/26/2012)

The cytotoxic effects of polymer-coated quantum dots and restrictions for live cell applications
(4882-4888)
Biomaterials 33  #19 (2012)
Soenen et al of Ghent University, Bekgium,used a multiparametric setup to determine the concentration at which common polymer-coated QDots become non-cytotoxic.  We found that toxic effects are strongly related to the intracellular QDot amount that can be controlled by their specific surface coating.  Using lysosomal buffer systems and proliferation-restricted cells, intracellular QDots were found to localize in endosomes, where they generate reactive oxygen species, interfere with cell cytoskeleton and leach free Cd2+ ions due to QDot dissolution, resulting in increased toxicity and impeded QDot fluorescence.  Furthermore, we find that asymmetric partitioning of QDots upon recurrent cell division results in the sacrifice of heavily-loaded cells and a rapid loss of particles in live cells, limiting the use of currently available QDots for long-term imaging and defining the non-cytotoxic concentration as 10-fold lower than commonly used concentrations.  (RDC 4/25/2012)

Nanomanufacturing with DNA Origami: Factors Affecting the Kinetics and Yield of Quantum Dot Binding
(pages 10151023)
Advanced Functional Materials 22  #5 (2012)
Ko, Gallatin and Liddle of National Institute of Standards and Technology, Maryland, generated nanopatterns of quantum dots on DNA origami with molecular precision. The quantitative studies of their binding kinetics show that the yield can be greatly improved by controlling many factors including the valency of the binding location, the biotin linker length, and the organization and spacing of the binding locations on the DNA.  (RDC 3/9/2012

8,080,229
Water soluble nanocrystalline quantum dots

Shih et al of Drexel University, Pennsylvania, developed an economic, direct synthetic method for producing water soluble QDs that are ready for bioconjugation.  The method can produce aqueous QDs with emission wavelengths varying from 400 nm to 700 nm. Highly luminescent metal sulfide (MS) QDs are produced via an aqueous synthesis route.  MS QDs are capped with thiol-containing charged molecules in a single step.  The resultant MS QDs exhibit the distinctive excitonic photoluminescence desired of QDs and can be fabricated to avoid undesirable broadband emissions at higher wavelengths.  This provides a significant improvement over the present complex and expensive commercial processes for the production of QDs. The aqueous QDs are stable in biological fluids over a long period of time. In addition, nontoxic ZnS QDs have been produced with good photoluminescence properties by refluxing the ZnS QD suspensions over a period of time.  (RDC 1/11/2011)

7,811,479
Polymer-nanocrystal quantum dot composites and optoelectronic devices

Drndic et al of the University of Pennsylvania has developed a semiconducting polymer, such as poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] ("MEH-PPV"), and PbSe nanocrystal quantum dots. These composite materials are useful in preparing optoelectronic devices, such as light emitting diodes, photovoltaic cells, lasers and photodetectors.  (RDC 1/7/2011)

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Roger D. Corneliussen
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Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
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** Date of latest addition; date of first entry is 1/7/2012.