教師著作
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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 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 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 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.Item Size Dependent Properties of CdSe Quantum Dots(American Physical Society, 2005-05-23) S. Neeleshwar; C.-L. Chen; C.-B. Tsai; Y.-Y. Chen; Chia-Chun Chen; S.-G. Shyu; M.-S. SeehraTemperature dependences of the magnetic susceptibility χ and heat capacity Cp of CdSe quantum dots with size d=2.8, 4.1, and 5.6 nm are compared to those of bulk CdSe to determine the size-dependent effects. With decreasing size d, the following effects are observed: (i) room temperature optical absorption shows a blueshift of the band gap; (ii) room temperature x-ray diffraction show wurtzite structure but with smaller lattice constants; (iii) magnetic susceptibility changes from negative (diamagnetic) for the bulk to positive χ with magnitude increasing with decreasing d; and (iv) the Sommerfeld constant γ determined from the Cp/T vs T2 data increases. Possible explanations for these size-dependent properties are presented.Item Selective Binding of Mannose-Encapsulated Gold Nanoparticles to Type I Pili in Escherichia Coli(American Chemical Society, 2002-04-10) C.-C. Lin; Y.-C. Yeh; C.-Y. Yang; C.-L. Chen; G.-F. Chen; Chia-Chun Chen; Y.-C. WuThe synthesis, characterization and biological application of mannose encapsulated gold nanoparticles (m-AuNP) are reported. m-AuNP is well dispersed and very stable without aggregation in the media of broad ion strength and pH ranges. The selective binding of m-AuNP to the mannose adhesin FimH of bacterial type 1 pili is demonstrated using transmission electron microscopy. The competition assay with free mannose suggests that m-AuNP binds FimH better than free mannose does. This work demonstrates that carbohydrate attached nanoparticles can be used as an efficient affinity label and a multi-ligand carrier in a biological system.