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Erogbogbo F.,State University of New York at Buffalo | Liu T.,Changchun University of Science and Technology | Liu T.,State University of New York at Buffalo | Liu T.,International Joint Research Center for Nanophotonics and Biophotonics | And 6 more authors.
ACS Nano | Year: 2011

Particle size is widely used to tune the electronic, optical, and catalytic properties of semiconductor nanocrystals. This contrasts with bulk semiconductors, where properties are tuned based on composition, either through doping or through band gap engineering of alloys. Ideally, one would like to control both size and composition of semiconductor nanocrystals. Here, we demonstrate production of silicon-germanium alloy nanoparticles by laser pyrolysis of silane and germane. We have used FTIR, TEM, XRD, EDX, SEM, and TOF-SIMS to conclusively determine their structure and composition. Moreover, we show that upon extended sonication in selected solvents, these bare nanocrystals can be stably dispersed without ligands, thereby providing the possibility of using them as an ink to make patterned films, free of organic surfactants, for device fabrication. The engineering of these SiGe alloy inks is an important step toward the low-cost fabrication of group IV nanocrystal optoelectronic, thermoelectric, and photovoltaic devices. © 2011 American Chemical Society. Source

Cai H.,International Joint Research Center for Nanophotonics and Biophotonics | Zhu J.,State University of New York at Buffalo | Chen G.,International Joint Research Center for Nanophotonics and Biophotonics | Liu L.,International Joint Research Center for Nanophotonics and Biophotonics | And 2 more authors.
Journal of Raman Spectroscopy | Year: 2011

As an infrared Raman probe, the molecule 3,3′- diethylthiatricarbocyanine iodide (DTTC) has received much attention in the past decades due to its potential applications in Raman imaging, single-cell detection, cancer diagnosis, and surface-enhanced Raman scattering (SERS). In this work, ordinary Raman, SERS, and theoretical Raman spectra were investigated to estimate the DTTC suspension. More specifically, the original gold nanospheres (60 nm diameter) and gold nanorods were encoded with DTTC and stabilized with a layer of thiol-polyethylene glycol as Raman reporter; SERS data were also obtained from the samples. Hartree-Fock theory and density functional theory (DFT) calculation were applied to calculate the optimized Raman spectra of DTTC in water on the B3LYP/6-31G level. Subsequently, the obtained experimental spectra from DTTC were carefully compared with the theoretically calculated spectra, and good agreement was obtained between the theoretical and experimental results.The bands between 500 and 3100 cm -1 in the ordinary Raman and SERS spectra were assigned as well. This work will facilitate the development of ultrasensitive SERS probes for advanced biomedical imaging applications. © 2011 John Wiley & Sons, Ltd. Source

Li S.,Changchun University of Science and Technology | Li S.,International Joint Research Center for Nanophotonics and Biophotonics | Xu D.,Jilin University | Shen H.,Jilin University | And 3 more authors.
Materials Research Bulletin | Year: 2012

With cetyltrimethylammonium bromide (CTAB) as a soft template, magnesium borate (Mg 2B 2O 5) one-dimensional micro/nanorods were synthesized. The products prepared in the absence of CTAB were Mg 2B 2O 5 nanoparticals and needles. However, using CTAB as a soft template the products were Mg 2B 2O 5 whiskers (diameter: 200 ± 10 nm, length: 1-2 μm). The formation mechanism was discussed. In addition, the experimental and theoretical Raman spectra of Mg 2B 2O 5 were reported for the first time, and the possible vibrations modes of Mg 2B 2O 5 crystals were assigned based on the calculation results. Copyright © 2012 Published by Elsevier Ltd. All rights reserved. Source

Liu L.,Changchun University of Science and Technology | Liu L.,State University of New York at Buffalo | Liu L.,International Joint Research Center for Nanophotonics and Biophotonics | Ding H.,State University of New York at Buffalo | And 14 more authors.
Plasmonics | Year: 2011

We report the use of biocompatible gold nanorods (GNRs) as multimodal (plasmonic and magnetic) probes for cancer cell labeling in vitro. These multifunctional and multimodal bioconjugates were prepared by replacing cetyltrimethylammonium bromide with a mixture of functionalized PEGylation molecules so that a variety of functionalities (e.g., magnetic resonance imaging agent gadolinium (Gd) and biorecognition molecule transferrin (Tf)) can be easily integrated using simple chemistry. It was shown that Gd incorporation did not interfere with the plasmonic properties of the GNRs and a strong T1 relaxivity was estimated (10.0 mM-1 s-1), which is more than twice that of the clinical MRI agent Gd-DTPA. The large observed T1 relaxivity was possibly due to the huge surface to volume ratio of GNR, which allowed huge amount of amine-terminated molecule to anchor on the surface, coupled with Gd (III) ions for the enhanced relaxation of water protons. Pancreatic cancer cell overexpressing the transferring receptor was served as the in vitro model, and the Tf-mediated uptake was demonstrated and confirmed by dark-field imaging and transmission electron microscopy. More importantly, cell viability (MTS) assay did not reveal any sign of toxicity in these treated cells, suggesting that PEGylated GNRs can serve as a biocompatible, multifunctional, and multimodal platform for variable bio-applications. © 2010 Springer Science+Business Media, LLC. Source

Liu L.-W.,Changchun University of Science and Technology | Liu L.-W.,International Joint Research Center for Nanophotonics and Biophotonics | Hu S.-Y.,Changchun University of Science and Technology | Hu S.-Y.,International Joint Research Center for Nanophotonics and Biophotonics | And 7 more authors.
Beilstein Journal of Nanotechnology | Year: 2014

In this study, we report on CdS/ZnS nanocrystals as a luminescence probe for bioimaging applications. CdS nanocrystals capped with a ZnS shell had enhanced luminescence intensity, stronger stability and exhibited a longer lifetime compared to uncapped CdS. The CdS/ZnS nanocrystals were stabilized in Pluronic F127 block copolymer micelles, offering an optically and colloidally stable contrast agents for in vitro and in vivo imaging. Photostability test exhibited that the ZnS protective shell not only enhances the brightness of the QDs but also improves their stability in a biological environment. An in-vivo imaging study showed that F127- CdS/ZnS micelles had strong luminescence. These results suggest that these nanoparticles have significant advantages for bioimaging applications and may offer a new direction for the early detection of cancer in humans. © 2014 Liu et al. Source

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