教師著作
Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/37076
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Item Photothermal cancer therapy via femtosecond-laser-excited FePt nanoparticles(Elsevier, 2013-01-01) C.-L. Chen; L.-R. Kuo; S.-Y. Lee; Y.-K. Hwu; S.-W. Chou; Chia-Chun Chen; F.-H. Chang; K.-H. Lin; D.-H. Tsai; Y.-Y. ChenFePt nanoparticles (NPs) have recently been revealed to be significant multifunctional materials for the applications of biomedical imaging, drug delivery and magnetic hyperthermia due to their novel magnetic properties. In this study, a newly discovered photothermal effect activated by the near infrared (NIR) femtosecond laser for FePt NPs was demonstrated. The threshold laser energy to destroy cancer cells was found to be comparable to that of gold nanorods (Au NRs) previously reported. Through the thermal lens technique, it was concluded that the temperature of the FePt NPs can be heated up to a couple of hundreds degree C in picoseconds under laser irradiation due to the excellent photothermal transduction efficiency of FePt NPs. This finding boosts FePt NPs versatility in multifunctional targeted cancer therapy.Item Surfactant-Directed Synthesis of Ternary Nanostructures: Nanocubes, Polyhedrons, Octahedrons, and Nanowires of PtNiFe.Their Shape-Dependent Oxygen Reduction Activity.(American Chemical Society, 2012-07-10) S.-W. Chou; J.-J. Shyue; C.-H. Chien; Chia-Chun Chen; Y.-Y. Chen; P.-T. ChouWe report a rational method for preparation of ternary alloy (PtNiFe) nanocrystals with various shapes. PtNiFe nanocubes, polyhedrons, and octahedrons are prepared via fine-tuning the alloy compositions and surfactants, so that the crystal facet–surfactant bindings on the growth seed can be well controlled. Nanowires grow in the cylindrical template built via high concentrations of oleylamine. In the electrocatalysis examination, it appears that the oxygen reduction reaction (ORR) activities of all PtNiFe nanostructures outperform that of commercial Pt catalyst in the electrolyte of HClO4 or H2SO4. In HClO4, the order of ORR activity is as follows: octahedrons ≈ nanowires > polyhedrons > nanocubes. PtNiFe nanostructures enclosed by a (111) plane, such as octahedrons and nanowires, give the highest ORR activities. Conversely, in H2SO4, the ORR activity of PtNiFe nanocubes enclosed by {100} facets is the highest among these nanostructures. The ORR activity increases in the order of nanowires ≈ octahedrons < polyhedrons, establishing a shape dependency in the ORR activity, which is valuable upon performing nanocatalysis in fuel cells.Item In vitro and in vivo Studies of FePt Nanoparticles for Dual Modal CT/MRI Molecular Imaging(American Chemical Society, 2010-09-29) S.-W. Chou; Y.-H. Shau; P.-C. Wu; Y.-S. Yang; D.-B. Shieh; Chia-Chun ChenThe water-solvable FePt nanoparticles of 3, 6, and 12 nm in diameter (3 nm-, 6 nm-, and 12 nm-FePt) were synthesized and applied as a dual modality contrast agent for CT/MRI molecular imaging. These nanoparticles present excellent biocompatibility and hemocompatibility in all test concentrations for the imaging contrast. The biodistribution analysis revealed the highest serum concentration and circulation half-life for 12 nm-FePt, followed by 6 nm-FePt then 3 nm-FePt. Thus, the 3 nm-FePt showed higher brain concentrations. Anti-Her2 antibody conjugated FePt nanoparticles demonstrated molecular expression dependent CT/MRI dual imaging contrast effect in MBT2 cell line and its Her2/neu gene knock out counterpart. Selective contrast enhancement of Her2/neu overexpression cancer lesions in both CT and MRI was found in tumor bearing animal after tail vein injection of the nanoparticles. The 12 nm-FePt outperformed 3 nm-FePt in both imaging modalities. These results indicate the potential of FePt nanoparticles to serve as novel multimodal molecular imaging contrast agents in clinical settings.Item Size-dependent magnetic parameters of fcc FePt nanoparticles: applications to magnetic hyperthermia(IOP Publishing, 2010-04-14) M. S. Seehra; V. Singh; P. Dutta; S. Neeleshwar; Y.-Y. Chen; C.-L. Chen; S.-W. Chou; Chia-Chun ChenFor nominal 3 and 9 nm FePt nanoparticles coated with oleylamine/oleic acid and having a face-centred-cubic (fcc) structure, temperature variations (5–300 K) of magnetization M, ac susceptibility χ' and χ'' for the frequency range fm = 0.1–1000 Hz and electron magnetic resonance (EMR) spectra at 9.28 GHz are reported. X-ray diffraction of the samples shows fcc structure with a lattice constant a = 3.84 Å and TEM characterization yields log-normal distributions of the particle sizes with average D = 3.15(0.16) nm and D = 8.70(0.12) nm for the 3 nm and 9 nm samples, respectively. M versus T data for the zero-field-cooled and field-cooled modes yield a blocking temperature TB = 15 K (85 K) for the 3 nm (9 nm) samples whereas the hysteresis loops at 5 K yield a coercivity Hc = 0 Oe (1.4 kOe). Analysis of the data of TB at different fm determined from the peaks in χ'' in ac susceptibility and the temperature variation of the EMR spectra are used to determine the following parameters of the Vogel–Fulcher relaxation for the 3 nm (9 nm) samples respectively: the attempt frequency fo = 8 × 1010 Hz (2 × 1012 Hz); inter-particle interaction temperature To = 3 K (33 K) and anisotropy Ka = 1.96 × 106 ergs cm−3 (4.3 × 105 ergs cm−3). The use of the above parameters for the calculations of the optimum size for magnetic hyperthermia is analysed and discussed.Item Direct evidence of type II band alignment in nanoscale P3HT/CdSe heterostructures(IOP Publishing, 2011-02-11) C.-H. Wang; C.-W. Chen; Y.-T. Chen; C.-T. Chen; Y.-F.Chen; S.-W. Chou; Chia-Chun ChenDue to inherent advantages of both constituent materials, organic/inorganic hybrid composites have attracted increasing attention. One of the fundamental issues needed to be resolved is their band alignment, which governs most of the electrical and optical properties. Here, we report the investigation of optical transition in poly(3-hexylthiophene) (P3HT)/CdSe nano-composites (NCs). It is found that the relaxation dynamics of photo-carriers in NCs is dominated by charge separation effects. Based on the band bending effect and the quantum confinement energy of electrons in the conduction band of CdSe quantum dots, we provide direct evidence of type II band alignment in P3HT/CdSe NCs. The establishment of a type II transition in NCs is very useful for the future design of efficient optoelectronic devices based on conjugated polymer/semiconductor hybrid systems.Item Controlled Growth and Magnetic Property of FePt Nanostructure: Cuboctahedron, Octapod, Truncated Cube and Cube(American Chemical Society, 2009-10-27) S.-W. Chou; C.-L. Zhu; S. Neeleshwar; C.-L. Chen; Y.-Y. Chen; Chia-Chun ChenThe strategy for shape control of alloy FePt nanocrystal was studied systematically. By the careful adjustments of reaction parameters in a solution reaction, surfactant−facet bindings on the growth seed were controlled delicately. FePt octapod, cuboctahedron, truncated cube, and nanocube were successfully prepared from cuboctahedral seed and examined by high-resolution transmission electron microscopy. The formations of FePt nanostructures were mainly attributed to the differences in the growth rate between the {111} and {100} planes of cuboctahedral seeds. The magnetic measurements showed that the order of volume, V(nanocube) > V(octapod) > V(cuboctahedron) obviously reflected the order of saturated magnetization (Ms), Ms (nanocube) > Ms (octapod) > Ms (cuboctahedron). Furthermore, the measurements of octapod exhibited the highest coercivity and blocking temperature because of its higher surface to volume ratio and more structural facets.Item Synthesis of Core/shell Metal Oxide/Polyaniline Nanocomposites and Hollow Polyaniline Capsules(IOP Publishing, 2007-07-11) C.-L. Zhu; S.-W. Chou; S.-F. He; W.-N. Liao; Chia-Chun ChenA double-surfactant-layer-assisted polymerization method was designed to prepare well-controlled core/shell metal oxide/polyaniline (c/s-MO/PANi) nanocomposites. Monodispersed and uniform core/shell nanocomposites including c/s-CuO/PANi, −Fe2O3/PANi, −In2O3/PANi and −Fe2O3/SiO2/PANi were successfully prepared using this polymerization method. By the removal of the cores for the resulting c/s-MO/PANi nanocomposites, hollow PANi capsules with different shapes and sizes were obtained. Our method provides a facile and effective way to design novel core/shell nanostructures with diverse functionality and high colloidal stability.Item Size-Controlled Ex-nihilo Ferromagnetism in Capped CdSe Quantum Dots(Wiley-VCH Verlag, 2008-05-05) M. S. Seehra; P. Dutta; S. Neeleshwar; Y.-Y. Chen; C.-L. Chen; C.-L. Dong; S.-W. Chou; Chia-Chun Chen; C.-L. ChangHysteresis loops in D = 1.8 nm CdSe-TOPO nanoparticles show ferromagnetism at 5 K and 300 K. Charge transfer from Cd to the Cd–O bond is shown by arrow in the Fourier transforms amplitudes of the EXAFS k2χ data at the Cd K-edge in the smaller 2.8 and 4.1 nm particles. This charge transfer produces holes in the Cd 4d band yielding ferromagnetism varying as 1/D with magnetic moment µ = 0.0075 µB per Cd surface atom.