Thursday, July 16, 2015

PolySciTech (www.polyscitech.com) provides a wide array of biodegradable block copolymers and reactive intermediates. Recently, researchers at the University of Nevada utilized PolySciTech mPEG-PLGA (PolyVivo AK051) and Mal-PEG-PLGA (Polyvivo AI075) to generate mixed micelles. These micelles were loaded with quantum dots, metallic based nanoparticles that are easily detected in the body and serve well as an imaging contrast agent, and had chlorotoxin, a component derived from scorpion venom which has shown a preference for binding to brain cancer cells, conjugated to the exterior of the micelle using a michael’s type thiol-maleimide reaction. The micelles were then introduced to cells and were observed to be specifically internalized by the U-87 brain tumor cells.  Read more: Chen, Siqi, Mojtaba Ahmadiantehrani, Nelson Publicover, Kenneth Hunter, and Xiaoshan Zhu. "Thermal Decomposition Based Synthesis of Ag-In-S/ZnS Quantum Dots and Their Chlorotoxin-Modified Micelles for Brain Tumor Cell Targeting." RSC Advances (2015). http://pubs.rsc.org/en/content/articlehtml/2015/ra/c5ra11250h


“Abstract: Cadmium-free silver-indium-sulfide (Ag-In-S or AIS) chalcopyrite quantum dots (QDs) as well as their core–shell structures (AIS/ZnS QDs) are being paid significant attention in biomedical applications because of their low toxicity and excellent optical properties. Here we report a simple and safe synthetic system to prepare high quality AIS and AIS/ZnS QDs using thermal decomposition. The synthetic system simply involves heating a mixture of silver acetate, indium acetate, and oleic acid in dodecanethiol at 170 °C to produce AIS QDs with a 13% quantum yield (QY). After ZnS shell growth, the produced AIS/ZnS QDs achieve a 41% QY. To facilitate phase transfer and bioconjugation of AIS/ZnS QDs for cellular imaging, these QDs were loaded into the core of PLGA–PEG (5kDa : 5kDa) based micelles to form AIS/ZnS QD-micelles. Cellular imaging studies showed that chlorotoxin-conjugated QD-micelles can be specifically internalized into U-87 brain tumor cells. This work discloses that the scalable synthesis of AIS/ZnS QDs and the facile surface/interface chemistry for phase transfer and bioconjugation of these QDs may open an avenue for the produced QD-micelles to be applied to the detection of endogenous targets expressed on brain tumor cells, or more broadly to cell- or tissue-based diagnosis and therapy.”


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