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Santra S.,National Center for Nanosciences and Technology of China | Kaittanis C.,National Center for Nanosciences and Technology of China | Kaittanis C.,2424 Research Parkway | Perez J.M.,National Center for Nanosciences and Technology of China | And 2 more authors.
Langmuir | Year: 2010

Herein we report the design and synthesis of multifunctional hyperbranched polyester-based nanoparticles and nanocomposites with properties ranging from magnetic, fluorescence, antioxidant and X-ray contrast. The fabrication of these nanostructures was achieved using a novel aliphatic and biodegradable hyperbranched polyester (HBPE) synthesized from readily available diethyl malonate. The polymer's globular structure with functional surface carboxylic groups and hydrophobic cavities residing in the polymer's interior allows for the formation of multifunctional polymeric nanoparticles, which are able to encapsulate a diversity of hydrophobic cargos. Via simple surface chemistry modifications, the surface carboxylic acid groups were modified to yield nanoparticles with a variety of surface functionalizations, such as amino, azide and propargyl groups, which mediated the conjugation of small molecules. This capability achieved the engineering of the HBPE nanoparticle surface for specific cell internalization studies and the formation of nanoparticle assemblies for the creation of novel nanocomposites that retained, and in some cases enhanced, the properties of the parental nanoparticle building blocks. Considering these results, the HBPE polymer, nanoparticles and composites should be ideal for biomedical, pharmaceutical, nanophotonics applications. © 2009 American Chemical Society.


Das S.,National Center for Nanosciences and Technology of China | Wolfson B.P.,National Center for Nanosciences and Technology of China | Tetard L.,National Center for Nanosciences and Technology of China | Tetard L.,2424 Research Parkway | And 7 more authors.
Environmental Science: Nano | Year: 2015

Anthropogenic nanomaterials (ANMs), once produced, will inevitably be present in the environment. Depending on their environmental stability and level of toxicity, ANMs raise some concern regarding their potential impact on the surrounding animal, aquatic and plant life. In this study, we demonstrate for the first time the effect of ultra-small size (<5 nm) semiconductor ANMs on the germination and growth of seeds of a snow pea model plant system (Pisum sativum) using a N-acetyl cysteine (NAC) coated core-shell CdS:Mn/ZnS Qdots as a heavy metal ion containing model ANM. We present combined results of fluorescence confocal, atomic force microscopy (AFM) and Raman imaging of quantum dot (Qdot) to track the uptake and localization (translocation) in plant tissue. It was found that Qdots were localized on the surface seed coat, epidermis and intercellular regions. The germination, growth and chlorophyll content of the seedlings were found to be strongly dependent on Qdot dosage and time of seed incubation with Qdots. Interestingly, no acute Cd metal toxicity was observed at Qdot concentration below 40 μg mL-1, and seed germination and growth processes were promoted. © 2015 The Royal Society of Chemistry.

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