|
149 – Small angle X-ray scattering study of interparticle spatial properties of nanoparticles assembled by DNA and thermosensitive co-polymers
Kristen Hamner1, klhamner@syr.edu, Detlef Smilgies2, Mathew M. Maye1. (1) Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States, (2) CHESS, Cornell University, Ithaca, New York 14850, United States
In this presentation we investigate the interparticle spatial properties of nanoparticles assembled into aggregates via DNA-mediated interactions. The novelty of our system is that each nanoparticle is co-functionalized with a thermosensitive block-copolymer whose critical temperature (TC) is 51 oC. Using synchrotron small angle X-ray scattering (SAXS) we have probed in-situ changes to interparticle distances, lattice constants, and crystal structure as a function of DNA length, polymer grafting density, and temperature. The role that DNA length and structure, as well as polymer conformation plays in the observed changes will be discussed
Sunday, September 8, 2013 06:00 PM
Nanoscience (06:00 PM – 08:00 PM)
Location: Indiana Convention Center
Room: Halls F&G
Monday, September 9, 2013 08:00 PM
Sci-Mix (08:00 PM – 10:00 PM)
Location: Indiana Convention Center
Room: Halls F&G
|
598 – Controlling composition, asymmetry, and internal microstructure of nanomaterials using a core/alloy approach
Patrick Lutz, pslutz@syr.edu, Wenjie Wu, Mathew M. Maye. Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
This presentation focuses on our recent nanoparticle synthesis strategy that employs atomic interdiffusion at a core/shell interface to produce alloy-terminated nanocrystals. These core/alloy nanoparticles have alloy compositions that are determined by shell thickness, processing temperature, initial core diameter, and surface capping ligand. As a proof of principle, we have fabricated an assortment of noble metal systems. The alloying is preceded by the layer-by-layer deposition of the shell material (i.e., Ag, Pd, Pt), followed by a microwave mediated hydrothermal annealing step, which induces core/shell inter diffusion and alloying. We show the extenstion of this approach to using the alloy phase behavior to drive asymmetric growth of heterostructures with janus-like interfaces. Moreover, we show that this approach can be extended to non noble metal alloys, whose rich oxidation behavior can be tuned by alloy shell composition and thickness. This results in tailorable Kirkendell diffusion and vacany coalescence, forming highly stable core-void-shell materials.
Monday, September 9, 2013 08:00 PM
Sci-Mix (08:00 PM – 10:00 PM)
Location: Indiana Convention Center
Room: Halls F&G
Wednesday, September 11, 2013 06:00 PM
Nanoscience (06:00 PM – 08:00 PM)
Location: Indiana Convention Center
Room: Halls F&G
|
|
57 – Investigating the drug binding properties and cytotoxicity of DNA-capped nanoparticles designed as delivery vehicles for the anticancer agents doxorubicin and actinomycin D
Colleen M. Alexander1, cmalex01@syr.edu, James C. Dabrowiak1,2, Mathew M. Maye1,2. (1) Department of Chemistry, Syracuse University, Syracuse, NY 13244, United States, (2) Syracuse Biomaterials Institute, Syracuse University, Syracuse, NY 13244, United States
In this presentation we will discuss the recently developed and implemented nanoscale drug delivery vehicle based on DNA-capped gold nanoparticles (NPs) and DNA intercalating chemotherapy drugs. Using the known DNA-intercalating properties of the clinically used anticancer drugs doxorubicin (DOX) and actinomycin D (ActD), we have designed double stranded DNA (dsDNA) capped NPs to load up to 200 drugs/NP using sequence specific intercalation. The properties of drug binding were probed by monitoring the melting transition of the dsDNA capping, by measuring the swelling of hydrodynamic diameter, and by changes to electrophoretic mobility. Dialysis was utilized to measure the off-rate and equilibrium binding constants associated with drug release. The cytotoxicity of these vehicles was measured using neuroblastoma cancer cells, and confocal microscopy was employed as a means of evaluating cellular uptake of DOX. We will also discuss a new multifunctional second-generation vehicle developed to enable targeted delivery and to control drug release.
Sunday, September 8, 2013 03:50 PM
Young Investigator Award Symposium (01:30 PM – 05:10 PM)
Location: Indiana Convention Center
Room: 130
|
|
404 – Investigating the role of polytypism in the growth of multishell CdSe/CdZnS quantum dots
Somak Majumber, smajumde@syr.edu, Mathew M. Maye. Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
In this presentation we investigate polytypism formation during the synthesis of giant quantum dots (gQDs) starting from CdSe cores with either zinc blende or wurtzite crystal structures. To these cores a CdxZn1-xS shell was deposited in a slow layer-by-layer SILAR process, and the final gQDs had sizes of >15 nm, with shapes and symmetry that were influenced by growth conditions. A systematic study of morphology and crystal structure change at each stage of shell growth was carried out by powder XRD, TEM, and HRTEM. The resulting photophysical properties were characterized by PL emission and decay studies. In both types of cores, shell growth was found to transition to wurtzite, whereas the percentage of polytypism was shown to alter both morphology and optical properties. The role that surface ligands play in the polytypism transition will also be discussed.
Tuesday, September 10, 2013 06:00 PM
Nanoscience (06:00 PM – 08:00 PM)
Location: Indiana Convention Center
Room: Halls F&G
|
220 – Stepwise assembly of multicolor qdot clusters using a DNA-mediated approach
Kaitlin Coopersmith, kcoopers@syr.edu, R. Davon Slaton, Hyunjoo Han, Mathew M. Maye. Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
In this presentation we describe the preparation of multi-color quantum dot clusters. Using purpose-built CdSe/ZnS quantum dots and rods modified with single stranded oligonucleotides (ssDNA), clusters with defined stoichiometry and emission wavelengths were constructed by DNA mediated interactions. To control stoichiometry and to improve assembly yields, the clusters were assembled and released in a step-wise manner at a colloidal solid support. The clusters optical characteristics were characterized by fluorescence spectroscopy and microscopy, and FRET analysis was utilized to probe energy transfer within the clusters. The cluster morphology and hydrodynamic properties were characterized by TEM and DLS, respectively. The use of these clusters for sensing and multi-color multiplexing will also be discussed.
Monday, September 9, 2013 06:00 PM
Fundamental Research in Colloid and Surface Science (06:00 PM – 08:00 PM)
Location: Indiana Convention Center
Room: Hall H
|
|
|
