Browsing by Author "Chen, Yu-Wei"

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A High-Sensitivity and Low-Power Theranostic Nanosystem for Cell SERS Imaging and Selectively Photothermal Therapy Using Anti-EGFR-Conjugated Reduced Graphene Oxide/Mesoporous Silica/AuNPs Nanosheets
(2016-03-16)
Chen, Yu-Wei
;
Liu, Ting-Yu
;
Chen, Po-Jung
;
Chang, Po-Hsueh
;
Chen, San-Yuan
A high-sensitivity and low-power theranostic nanosystem that combines with synergistic photothermal therapy and surface-enhanced Raman scattering (SERS) mapping is constructed by mesoporous silica self-assembly on the reduced graphene oxide (rGO) nanosheets with nanogap-aligned gold nanoparticles (AuNPs) encapsulated and arranged inside the nanochannels of the mesoporous silica layer. Rhodamine 6G (R6G) as a Raman reporter is then encapsulated into the nanochannels and anti-epidermal growth factor receptor (EGFR) is conjugated on the nanocomposite surface, defined as anti-EGFR-PEG-rGO@CPSS-Au-R6G, where PEG is polyethylene glycol and CPSS is carbon porous silica nanosheets. SERS spectra results show that rGO@CPSS-Au-R6G enhances 5 x 10(6) magnification of the Raman signals and thus can be applied in the noninvasive cell tracking. Furthermore, it displays high sensitivity (detection limits: 10(-8) M R6G solution) due to the "hot spots" effects by the arrangements of AuNPs in the nanochannels of mesoporous silica. The highly selective targeting of overexpressing EGFR lung cancer cells (A549) is observed in the anti-EGFR-PEG-rGO@CPSS-Au-R6G, in contrast to normal cells (MRC-5). High photothermal therapy efficiency with a low power density (0.5 W cm(-2)) of near-infrared laser can be achieved because of the synergistic effect by conjugated AuNPs and rGO nanosheets. These results demonstrate that the anti-EGFR-PEG-rGO@CPSS-Au-R6G is an excellent new theranostic nanosystem with cell targeting, cell tracking, and photothermal therapy capabilities.
A Ka-Band Scalable Hybrid Phased Array Based on Four-Element ICs
(2020-01-01)
Chu, Ching-Yun
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Chen, Yuan-Pu
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Gao, Jing-Zhi
;
Ke, Cheng-Yung
;
Chen, Yu-Wei
In this article, a scalable hybrid phased-array system is presented through synchronization, analog complex weighting, and digital beamforming of numerous fully integrated Ka-band four-receiver (RX)/four-transmitter (TX) phased-array transceiver integrated circuits (ICs). A 1.09-GHz clock synchronizes the local oscillator (LO) and a 50-MHz clock synchronizes analog-to-digital (A/D)/digital-to-analog (D/A) converters for all array elements. Phase shifting is first accomplished in the analog domain using optimal intermediate frequency (IF)/LO complex weighting and signal summing in the 4RX/4TX IC to reduce the number of signals by a factor of four, followed by A/D sampling and digital beamforming in field-programmable gate arrays (FPGAs) and central processing units (CPUs). Phase-shifting properties, programmable gain variations, and antenna patterns of each RTX channel are measured and tabulated to calculate the optimal channel weights. The long-term phase stability is enhanced through temperature control by monitoring all ICs' temperatures in real time and adaptively adjusting the duty cycle of the TX mode of each IC to limit instantaneous temperature variations to +/- 0.5 degrees C over each calibration session. This reduces random phase errors from 13.3 degrees to 4.8 degrees in the TX mode. After each Vivaldi antenna is located on a 2-D rectangular grid, an 8 x 4 subarray module with synchronized digital output is demonstrated. With the boresight pointing along the x-axis, the eight-element dimension pointing along the y-axis, and the four-element dimension pointing along the z-axis, this subarray steers radiation patterns with the E-field polarized to the y-axis between +/- 40 degrees in both azimuth and elevation with 13.4 degrees and 26.4 degrees measured 3-dB beamwidths, respectively.
A theranostic nrGO@MSN-ION nanocarrier developed to enhance the combination effect of sonodynamic therapy and ultrasound hyperthermia for treating tumor
(2016)
Chen, Yu-Wei
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Liu, Tse-Ying
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Chang, Po-Hsueh
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Hsu, Po-Hung
;
Liu, Hao-Li
Sonodynamic therapy (SDT), which induces activation of sonosensitizers in cancer cells through ultrasound irradiation, has emerged as an alternative and promising noninvasive therapeutic approach to kill both superficial and deep parts of tumors. In this study, mesoporous silica (MSN) grown on reduced graphene oxide nanosheet (nrGO) capped with Rose Bengal (RB)-PEG-conjugated iron-oxide nanoparticles (IONs), nrGO@MSN-ION-PEG-RB, was strategically designed to have targeted functionality and therapeutic efficacy under magnetic guiding and focused ultrasound (FUS) irradiation, respectively. The singlet oxygen produced by ultrasound-activated RB and the ultrasound-induced heating effect was enhanced by rGO and IONs, which improved the cytotoxic effect in cancer cells. In an animal experiment, we demonstrated that the combination of sonodynamic/hyperthermia therapy with magnetic guidance using this nanocomposite therapeutic agent can produce remarkable efficacious therapy in tumor growth inhibition. Furthermore, the combination effect induced by FUS irradiation produces significant damage to both superficial and deep parts of the targeted tumor.
Automated Segmentation and Quantification of White Matter Hyperintensities in Acute Ischemic Stroke Patients with Cerebral Infarction
(2014-08-15)
Tsai, Jang-Zern
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Peng, Syu-Jyun
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Chen, Yu-Wei
;
Wang, Kuo-Wei
;
Li, Chen-Hua
White matter hyperintensities (WMHs) of presumed vascular origin are common in ageing population, especially in patients with acute cerebral infarction and the volume has been reported to be associated with mental impairment and the risk of hemorrhage from antithrombotic agents. WMHs delineation can be computerized to minimize human bias. However, the presence of cerebral infarcts greatly degrades the accuracy of WMHs detection and thus limits the application of computerized delineation to patients with acute cerebral infarction. We propose a computer-assisted segmentation method to depict WMHs in the presence of cerebral infarcts in combined T1-weighted, fluid attenuation inversion recovery, and diffusion-weighted magnetic resonance imaging (MRI). The proposed method detects WMHs by empirical threshold and atlas information, with subtraction of white matter voxels affected by acute infarction. The method was derived using MRI from 25 hemispheres with WMHs only and 13 hemispheres with both WMHs and cerebral infarcts. Similarity index (SI) and correlation were utilized to assess the agreement between the new automated method and a gold standard visually guided semi-automated method done by an expert rater. The proposed WMHs segmentation approach produced average SI, sensitivity and specificity of 83.142 +/- 11.742, 84.154 +/- 16.086 and 99.988 +/- 0.029% with WMHs only and of 68.826 +/- 14.036, 74.381 +/- 18.473 and 99.956 +/- 0.054% with both WMHs and cerebral infarcts in the derivation cohort. The performance of the proposed method with an external validation cohort was also highly consistent with that of the experienced rater.
Automatic Detection and Quantification of Acute Cerebral Infarct by Fuzzy Clustering and Histographic Characterization on Diffusion Weighted MR Imaging and Apparent Diffusion Coefficient Map
(2014)
Tsai, Jang-Zern
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Peng, Syu-Jyun
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Chen, Yu-Wei
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Wang, Kuo-Wei
;
Wu, Hsiao-Kuang
Determination of the volumes of acute cerebral infarct in the magnetic resonance imaging harbors prognostic values. However, semiautomatic method of segmentation is time-consuming and with high interrater variability. Using diffusion weighted imaging and apparent diffusion coefficient map from patients with acute infarction in 10 days, we aimed to develop a fully automatic algorithm to measure infarct volume. It includes an unsupervised classification with fuzzy C-means clustering determination of the histographic distribution, defining self-adjusted intensity thresholds. The proposed method attained high agreement with the semiautomatic method, with similarity index 89.9 +/- 6.5%, in detecting cerebral infarct lesions from 22 acute stroke patients. We demonstrated the accuracy of the proposed computer-assisted prompt segmentation method, which appeared promising to replace the laborious, time-consuming, and operator-dependent semiautomatic segmentation.
Characterization and drug release behavior of highly responsive chip-like electrically modulated reduced graphene oxide-poly(vinyl alcohol) membranes
(2012)
Liu, Heng-Wen
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Hu, Shang-Hsiu
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Chen, Yu-Wei
;
Chen, San-Yuan
;
材料科學與工程學系
"Hybrid hydrogel membranes composed of reduced graphene oxide (rGO) nanosheets and a poly (vinyl alcohol) (PVA) matrix were investigated as an electrically responsive drug release system. The rGO nanosheets in the matrix act as a physical barrier to inhibit the release of the model anesthetic drug, lidocaine hydrochloride, but the highly responsive release can be enhanced by the presence of rGO when exposed to an electrical stimulus. More interestingly, the on-demand drug release profiles of the assembled rGO-PVA hydrogel into a chip-like device can be highly controlled by an external electrical field. Release profiles ranging from a slow-elution pattern to a rapid release under electrical field treatment can be achieved by manipulating the rGO-PVA composition. Moreover, under cyclic exposure to an electrical stimulus, a highly controllable and repeatedly pulsatile release with desirable precision is obtained from the rGO-PVA hydrogel, implying that the hydrogel exhibits excellent anti-fatigue properties. By combining with the enhanced structural integrity and biocompatibility, the electrically responsive rGO-PVA hydrogel has demonstrated potential biological applications in drug delivery systems. In addition, the easy loading of hydrophilic drugs into the rGO-PVA hydrogel opens up a promising future in biological applications, such as transdermal therapy and wound healing."
Effect of Oxygen on the Microstructural Growth and Physical Properties of Transparent Conducting Fluorine-Doped Tin Oxide Thin Films Fabricated by the Spray Pyrolysis Method
(2013)
Chantarat, N.
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Chen, Yu-Wei
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Hsu, Shu-Han
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Lin, Chin-Ching
;
Chiang, Mei-Ching
We reported the fabrication of an FTO conducting thin film via a spray deposition method, which was used to investigate the effect of oxygen content in the carrier gas on deposited film morphology and properties. Using a carrier gas containing various O-2/N-2 concentrations (0%, 20%, 50%, 80%, and 100%) led to significant changes in the thickness, size, and shape of grain growth. The deposited films with 0-50% oxygen content yielded a low resistivity of similar to 10(-4) Omega-cm and a transmittance in the range of 76-96% at 550 nm. Furthermore, by changing the carrier gas concentration, the FTO films displayed different charge transport, recombination, and collection properties due to the surface and interfacial effects. These films with modified properties can be applied to dye-sensitized solar cells (DSSCs). Overall, the conversion efficiency of a solar cell based on a 0% O-2 sample was increased by approximately 2% from that of a 100% O-2 sample. The higher efficiency is mainly the result of the lower O-2 content, which minimized the grain boundaries (spacing) and improved the electron transport on the FTO film surface. (C) 2013 The Electrochemical Society. All rights reserved.
Enhanced UV photoresponse in nitrogen plasma ZnO nanotubes
(2009-09-30)
Chantarat, N.
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Chen, Yu-Wei
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Chen, San-Yuan
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Lin, Chin-Ching
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材料科學與工程學系
The photoresponse behavior of one-dimensional ZnO nanowires (NWs) and nanotubes (NTs) grown on ITO-coated glass substrates via a wet-chemical route was investigated. The photoluminescence spectra exhibited a decrease in the deep-level intensity, indicating that the oxygen defects and impurities are occupied by the presence of N ions in the ZnO NT matrix after a nitrogen plasma treatment. I-V tests demonstrate an enhanced dark current (4.83 x 10(-7) A) after an extended plasma treatment of up to 900s for ZnO NTs compared to that (0.571 x 10(-7) A) of NWs. Furthermore, the ZnO NTs show the highest reliable photoresponse, 20 times that of NWs under UV irradiation (325 nm) in air at room temperature. It is believed that nitrogen plasma ZnO nanotubes can potentially be useful in the designs of 1D ZnO-based solar cells and optoelectronic devices.
Functionalized graphene nanocomposites for enhancing photothermal therapy in tumor treatment
(2016-10-01)
Chen, Yu-Wei
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Su, Yu-Lin
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Hu, Shang-Hsiu
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Chen, San-Yuan
;
材料科學與工程學系
Graphene and its derivatives have unique physical and chemical properties that make them promising vehicles for photothermal therapy (PTT)-based cancer treatment. With intrinsic near-infrared (NIR) absorption properties, graphene-based nanomaterials can be used for PTT and other therapeutics, particularly in combination therapy, to provide successful thermal ablation of cancer cells. In the recent years, advances in graphene-based PTT have produced efficient and efficacious tumor inhibition via nanomaterial structural design and different functionalizations of graphene-derived nanocomposites. Graphene-based nanosystems exhibit multifunctional properties that are useful for PTT applications including enhancement of multimodalities, guided imaging, enhanced chemotherapy and low-power efficient PTT for optimum therapeutic efficiency. Therefore, in this review, we address critical issues and future aspects of PTT-based combination therapy. (C) 2016 Elsevier B.V. All rights reserved.
Improvement in photovoltaic performance for hybrid P3HT/elongated CdS nanocrystals solar cells with F-doped SnO(2) arrays
(2010-01-01)
Liao, Hung-Chou
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Lin, Chin-Ching
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Chen, Yu-Wei
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Liu, Ta-Chung
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Chen, San-Yuan
Hybrid CdS/P3HT photovoltaic devices using F-doped SnO(2) (FTO)-coated ZnO nanorod arrays as electrodes were studied in this work. The crystalline FTO, made using low-cost spray pyrolysis deposition (SPD), displayed a nominally complete and uniform coating over the entire outer surface of the ZnO nanorods. The photovoltaic performance of the CdS/P3HT photovoltaic devices increased with the FTO-coated ZnO nanorod length and thickness of the FTO layer, due to improvement in collecting photogenerated electrons, which results in the increased short circuit current density (J(SC)) and fill factor (FF) of the devices. The incorporation of CdS into the P3HT greatly enhanced the JSC of the devices with a nanorod FTO electrode. The power conversion efficiency (PCE) of the device with a ZnO nanorod length of 320 nm was increased from 0.37% for P3HT without CdS to 1.8% with CdS of AR = 1 (spherical shape). With a further increase of the AR of the CdS nanocrystal to 4, the PCE was further increased up to 2.6%. However, longer CdS nanocrystals conversely caused deterioration in PCE as a result of the nanorod array morphology. These results indicate that, although increased nanorod length could improve the photocurrent and efficiency, other factors, such as P3HT infiltration, nanorod array morphology and CdS nanocrystal length are required for obtaining the optimal performance of these devices.
Improvement in photovoltaic performance for hybrid P3HT/elongated CdS nanocrystals solar cells with F-doped SnO2 arrays
(2010-01-01)
Liao, Hung-Chou
;
Lin, Chin-Ching
;
Chen, Yu-Wei
;
Liu, Ta-Chung
;
Chen, San-Yuan
Hybrid CdS/P3HT photovoltaic devices using F-doped SnO2 (FTO)-coated ZnO nanorod arrays as electrodes were studied in this work. The crystalline FTO, made using low-cost spray pyrolysis deposition (SPD), displayed a nominally complete and uniform coating over the entire outer surface of the ZnO nanorods. The photovoltaic performance of the CdS/P3HT photovoltaic devices increased with the FTO-coated ZnO nanorod length and thickness of the FTO layer, due to improvement in collecting photogenerated electrons, which results in the increased short circuit current density (J(SC)) and fill factor (FF) of the devices. The incorporation of CdS into the P3HT greatly enhanced the JSC of the devices with a nanorod FTO electrode. The power conversion efficiency (PCE) of the device with a ZnO nanorod length of 320 nm was increased from 0.37% for P3HT without CdS to 1.8% with CdS of AR = 1 (spherical shape). With a further increase of the AR of the CdS nanocrystal to 4, the PCE was further increased up to 2.6%. However, longer CdS nanocrystals conversely caused deterioration in PCE as a result of the nanorod array morphology. These results indicate that, although increased nanorod length could improve the photocurrent and efficiency, other factors, such as P3HT infiltration, nanorod array morphology and CdS nanocrystal length are required for obtaining the optimal performance of these devices.
In situ DOX-calcium phosphate mineralized CPT-amphiphilic gelatin nanoparticle for intracellular controlled sequential release of multiple drugs
(2015-03-15)
Li, Wei-Ming
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Su, Chia-Wei
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Chen, Yu-Wei
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Chen, San-Yuan
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材料科學與工程學系
A co-delivery strategy has been developed to achieve the synergistic effect of a hydrophobic drug (camptothecin, CPT) and a hydrophilic drug (doxorubicin, DOX) by utilizing the unique structure of amphiphilic gelatin/camptothecin @calcium phosphate-doxorubicin (AG/CPT@CaP-DOX) nanoparticles as a carriers in order to replace double emulsions while preserving the advantages of inorganic materials. The hydrophobic agent (CPT) was encapsulated via emulsion with an amphiphilic gelatin core, and subsequently mineralized by CaP-hydrophilic drug (DOX) through precipitation to form a CaP shell on the CPT-AG amphiphilic gelatin core so that drug molecules with different characteristics (i.e. hydrophobic and hydrophilic) can be encapsulated in different regions to avoid their interaction. The existence of the CaP shell can protect the DOX against free release and cause an increased transfer of DOX across membranes, overcoming multidrug resistance. Release studies from core-shell carriers showed the possibility of achieving sequential release of more than one type of drug by controlling the pH-sensitive CaP shell and degradable AG core. The highly pH-responsive behavior of the carrier can modulate the dual-drug-release of DOX/CPT, specifically in acidic intracellular pH environments. The AG/CPT@CaP-DOX nanoparticles also exhibited higher drug efficiencies against MCF-7/ADR cells than MCF-7 cells, thanks to a synergistic cell cycle arrest/apoptosis-inducing effect between CPT and DOX. As such, this core shell system can serve as a general platform for the localized, controlled, sequential delivery of multiple drugs to treat several diseases, especially for multidrug-resistant cancer cells. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
NIR-Triggered Synergic Photo-chemothermal Therapy Delivered by Reduced Graphene Oxide/Carbon/Mesoporous Silica Nanocookies
(2014-01-01)
Chen, Yu-Wei
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Chen, Po-Jung
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Hu, Shang-Hsiu
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Chen, I-Wei
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Chen, San-Yuan
Nitrogen Plasma-Assisted Codoped P-type (In, N):SnO(2) Ultra-Fine Thin Films and N-ZnO/p-In:SnO(2) Core-Shell Heterojunction Diodes Fabricated by an Ultrasonic Spray Pyrolysis Method
(2011-11-24)
Chantarat, N.
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Chen, Yu-Wei
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Lin, Chin-Ching
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Chiang, Mei-Ching
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Chen, Yu-Chun
In this study, tin oxide (SnO(2)) solution mixtures containing indium (In) of 0%, 3%, 7%, 15%, and 30% were used to fabricate In- and N-codoped SnO(2) films on glass at 400 degrees C using an ultrasonic spray pyrolysis method combined with thermal annealing at 600 degrees C and post nitrogen plasma treatment. X-ray diffraction analysis demonstrated that the incorporation of elemental In in the SnO(2) film primarily induces the evolution of crystalline phases from In-doped SnO(2) to Sn-doped In(2)O(3), depending on the doping concentration. Upon exposure to N plasma, the dark current dramatically increases in proportion to the treatment duration (5-40 min); the dark current can be enhanced for the 3% and 7%-doped samples by as much as 3 orders of magnitude compared to the untreated samples. Hall measurements confirmed that hole carriers could dominate the SnO(2) host matrix to promote p-type properties at a low In content (3% and 7%) with an increase in resistance compared to undoped samples. However, samples with higher In content (15% and 30%) showed the opposite trend, due to the formation of a secondary phase of n-type In(2)O(3). X-ray photoelectron spectroscopy was used to probe the incorporation and dissociation of chemical bonds between the doped In and N atoms in the SnO(2). Moreover, depth profile measurements showed a correlation between the elemental compositions and elemental distributions of the codoped SnO(2) film. Current-voltage (I-V) characterization revealed the improved behavior of heterojunction diodes consisting of a p-type (In, N)-doped SnO(2) thin film deposited on n-type ZnO nanorod arrays.
Nitrogen Plasma-Assisted Codoped P-type (In, N):SnO2 Ultra-Fine Thin Films and N-ZnO/p-In:SnO2 Core-Shell Heterojunction Diodes Fabricated by an Ultrasonic Spray Pyrolysis Method
(2011-11-24)
Chantarat, N.
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Chen, Yu-Wei
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Lin, Chin-Ching
;
Chiang, Mei-Ching
;
Chen, Yu-Chun
In this study, tin oxide (SnO2) solution mixtures containing indium (In) of 0%, 3%, 7%, 15%, and 30% were used to fabricate In- and N-codoped SnO2 films on glass at 400 degrees C using an ultrasonic spray pyrolysis method combined with thermal annealing at 600 degrees C and post nitrogen plasma treatment. X-ray diffraction analysis demonstrated that the incorporation of elemental In in the SnO2 film primarily induces the evolution of crystalline phases from In-doped SnO2 to Sn-doped In2O3, depending on the doping concentration. Upon exposure to N plasma, the dark current dramatically increases in proportion to the treatment duration (5-40 min); the dark current can be enhanced for the 3% and 7%-doped samples by as much as 3 orders of magnitude compared to the untreated samples. Hall measurements confirmed that hole carriers could dominate the SnO2 host matrix to promote p-type properties at a low In content (3% and 7%) with an increase in resistance compared to undoped samples. However, samples with higher In content (15% and 30%) showed the opposite trend, due to the formation of a secondary phase of n-type In2O3. X-ray photoelectron spectroscopy was used to probe the incorporation and dissociation of chemical bonds between the doped In and N atoms in the SnO2. Moreover, depth profile measurements showed a correlation between the elemental compositions and elemental distributions of the codoped SnO2 film. Current-voltage (I-V) characterization revealed the improved behavior of heterojunction diodes consisting of a p-type (In, N)-doped SnO2 thin film deposited on n-type ZnO nanorod arrays.
Photoconductive Enhancement of Single-Layer Tin Oxide-Coated ZnO Nanowires
(2010)
Lin, Chin-Ching
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Chen, Yu-Wei
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Chiang, Mei-Ching
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Lee, Chia-Hua
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Tung, Yung-Liang
In this study, zinc oxide nanowires (ZnO NWs) coated with crystalline tin oxide (SnO(2)) by an ultrasonic spray pyrolysis were investigated. High resolution transmission electron microscopy analysis confirms that a continuous single SnO(2) layer of about 10 nm has been coated on the ZnO NWs. Photoconductivity measurements revealed that the ZnO NWs coated with the single uniform SnO(2) layer had a higher photoconductivity ratio by about a factor of 8 compared to the pristine ZnO NWs, attributed to the multi-photoexcited electrons. Under a steady radiation of UV light (lambda=325 nm), a substantial increase in the steady-state photocurrent is noticeable, suggesting that extra photoinduced charges are transferred from SnO(2) to ZnO NWs.
Photoresponsive Protein-Graphene-Protein Hybrid Capsules with Dual Targeted Heat-Triggered Drug Delivery Approach for Enhanced Tumor Therapy
(2014-07-01)
Hu, Shang-Hsiu
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Fang, Ren-Hong
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Chen, Yu-Wei
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Liao, Bang-Jie
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Chen, I-Wei
A novel photo-responsive protein-graphene-protein (PGP) capsule that doubles as a photothermal agent with core/shell structure is constructed by anchoring reduced graphene oxide nanosheets on one-component protein (lactoferrin) shell through a double emulsion method. PGP capsules can transport fully concealed hydrophilic anticancer cargo, doxorubicin (Dox), with a large payload (9.43 mu mol g(-1)) to be later unloaded in a burst-like manner by photo-actuation triggered by near-infrared irradiation. Being bio-compatible yet with a high cancer cell targeting efficiency, PGP capsules have successfully eradicated subcutaneous tumors in 10 d following a single 5 min NIR irradiation without distal damage. Besides, the photochemothermal therapy of PGP capsules eradicates tumor cells not only in the light-treating area but also widely light-omitted tumor cells, overcoming the tumor recurrence due to efficient cell killing efficacy. These results demonstrate that the PGP capsule is a potential new drug delivery platform for local-targeting, on-demand, photoresponsive, combined chemotherapy/hyperthermia for tumor treatment and other biomedical applications.
Photoresponsive Protein-Graphene-Protein Hybrid Capsules with Dual Targeted Heat-Triggered Drug Delivery Approach for Enhanced Tumor Therapy
(2014-07-01)
Hu, Shang-Hsiu
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Fang, Ren-Hong
;
Chen, Yu-Wei
;
Liao, Bang-Jie
;
Chen, I-Wei
A novel photo-responsive protein-graphene-protein (PGP) capsule that doubles as a photothermal agent with core/shell structure is constructed by anchoring reduced graphene oxide nanosheets on one-component protein (lactoferrin) shell through a double emulsion method. PGP capsules can transport fully concealed hydrophilic anticancer cargo, doxorubicin (Dox), with a large payload (9.43 mu mol g(-1)) to be later unloaded in a burst-like manner by photo-actuation triggered by near-infrared irradiation. Being bio-compatible yet with a high cancer cell targeting efficiency, PGP capsules have successfully eradicated subcutaneous tumors in 10 d following a single 5 min NIR irradiation without distal damage. Besides, the photochemothermal therapy of PGP capsules eradicates tumor cells not only in the light-treating area but also widely light-omitted tumor cells, overcoming the tumor recurrence due to efficient cell killing efficacy. These results demonstrate that the PGP capsule is a potential new drug delivery platform for local-targeting, on-demand, photoresponsive, combined chemotherapy/hyperthermia for tumor treatment and other biomedical applications.
Quantum-Dot-Tagged Reduced Graphene Oxide Nanocomposites for Bright Fluorescence Bioimaging and Photothermal Therapy Monitored In Situ
(2012-04-03)
Hu, Shang-Hsiu
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Chen, Yu-Wei
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Hung, Wen-Ting
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Chen, I-Wei
;
Chen, San-Yuan
Quantum-dot-tagged reduced graphene oxide (QD-rGO) nanocomposites (left) internalized into targeted tumor cells display bright fluorescence from the QDs (right); by absorbing NIR radiation incident on the rGO and converting it into heat, they also cause simultaneous cell death and fluorescence reduction (bottom). The nanocomposite is thus capable of tumor imaging, photothermal therapy and in situ monitoring of treatment in progress.
Selective Oxygen-Plasma-Etching Technique for the Formation of ZnO-FTO Heterostructure Nanotubes and Their Rectified Photocatalytic Properties
(2010-12-06)
Chantarat, N.
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Chen, Yu-Wei
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Lin, Chin-Ching
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Chiang, Mei-Ching
;
Chen, San-Yuan
A novel ZnO-FTO heterostructure nanotube array was produced by combining a chemical solution process with oxygen-plasma etching. In this approach, presynthesized ZnO nanorod arrays act as templates, and FTO nanoparticles are deposited onto the ZnO nanorods by a simple spray pyrolysis method. X-ray photoelectron spectroscopy analysis demonstrated that the oxygen-plasma treatment decreased the O(2-)/OH(-) concentration ratio, resulting in dissociation of the Zn-O bonds and the outward diffusion of Zn cations to form an interior hollow, which is related to the formation of the hydroxyl functional group, Sn-OH, at the FTO surface. An etching evolution mechanism of the ZnO-FTO nanotubes via oxygen plasma was tentatively proposed in this study. Time-dependent photocurrent (I-T) measurements under ON-OFF cycles of UV illumination confirm that the 20-min etched sample exhibits a rectified photoresponse characteristic and a dark current increased by about 3 orders of magnitude over that of the unetched sample, which is attributed to the increased carrier concentration created at the surface conductive layer. This investigation offers an alternative selective etching method to lay the framework for nanoscale three-dimensional electrodes for solar-cell applications.