scholarly journals The Effect of Gold Nanorods Clustering on Near-Infrared Radiation Absorption

2018 ◽  
Vol 8 (7) ◽  
pp. 1132 ◽  
Author(s):  
Xi Gu ◽  
Victoria Timchenko ◽  
Guan Heng Yeoh ◽  
Leonid Dombrovsky ◽  
Robert Taylor
Keyword(s):  
Heat Generation ◽  
Gold Nanorods ◽  
Near Infrared ◽  
Volume Fraction ◽  
Resonant Absorption ◽  
Absorption Efficiency ◽  
Maximum Absorption ◽  
Radiation Absorption ◽  
Nir Light ◽  
Rate Of Increase

In this paper, the plasmonic resonant absorption of gold nanorods (GNRs) and GNR solutions was studied both numerically and experimentally. The heat generation in clustered GNR solutions with various concentrations was measured by exposing them to Near Infrared (NIR) light in experiment. Correspondingly, calculations based on the discrete-dipole approximation (DDA) revealed the same relationship between the maximum absorption efficiency and the nanorod orientation for the incident radiation. Additionally, both the plasmonic wavelength and the maximum absorption efficiency of a single nanorod were found to increase linearly with increasing aspect ratio (for a fixed nanorod volume). The wavelength of the surface plasmonic resonance (SPR) was found to change when the gold nanorods were closely spaced. Specifically, both a shift and a broadening of the resonance peak were attained when the distance between the nanorods was set to about 50 nm or less. The absorbance spectra of suspended nanorods at various volume fractions also showed that the plasmonic wavelength of the nanorods solution was at 780 ± 10 nm, which was in good agreement with the computational predictions for coupled side-by-side nanorods. When heated by NIR light, the rate of increase for both the temperature of solution and the absorbed light diminished when the volume fraction of suspended nanorods reached a value of 1.24×10−6. This matches with expectations for a partially clustered suspension of nanorods in water. Overall, this study reveals that particle clustering should be considered to accurately gauge the heat generation of the GNR hyperthermia treatments.

scholarly journals Photothermal Therapy Using Gold Nanorods and Near-Infrared Light in a Murine Melanoma Model Increases Survival and Decreases Tumor Volume

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mary K. Popp ◽  
Imane Oubou ◽  
Colin Shepherd ◽  
Zachary Nager ◽  
Courtney Anderson ◽  
...  
Keyword(s):  
Light Source ◽  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Tumor Volume ◽  
Infrared Light ◽  
Led Light ◽  
Murine Melanoma ◽  
Nir Light ◽  
Melanoma Model

Photothermal therapy (PTT) treatments have shown strong potential in treating tumors through their ability to target destructive heat preferentially to tumor regions. In this paper we demonstrate that PTT in a murine melanoma model using gold nanorods (GNRs) and near-infrared (NIR) light decreases tumor volume and increases animal survival to an extent that is comparable to the current generation of melanoma drugs. GNRs, in particular, have shown a strong ability to reach ablative temperatures quickly in tumors when exposed to NIR light. The current research tests the efficacy of GNRs PTT in a difficult and fast growing murine melanoma model using a NIR light-emitting diode (LED) light source. LED light sources in the NIR spectrum could provide a safer and more practical approach to photothermal therapy than lasers. We also show that the LED light source can effectively and quickly heatin vitroandin vivomodels to ablative temperatures when combined with GNRs. We anticipate that this approach could have significant implications for human cancer therapy.

scholarly journals PREPARATION AND CHARACTERIZATION OF A NEAR-INFRARED LIGHT RESPONSIVE MICROCAPSULE SYSTEM FOR CANCER THERAPY

2014 ◽  
Vol 07 (01) ◽  
pp. 1350037 ◽  
Author(s):  
YINGFENG DI ◽  
SISI CUI ◽  
YUEQING GU
Keyword(s):  
Cancer Therapy ◽  
Gold Nanorods ◽  
Self Assembly ◽  
Near Infrared ◽  
Infrared Light ◽  
Layer By Layer ◽  
Near Infrared Light ◽  
Nir Light ◽  
Alternative Material ◽  
Confocal Fluorescence Imaging

A novel near-infrared light responsive microcapsule system, gold nanorod-covered DOX-loaded hollow CaCO 3 microcapsule ( AuNR -HM-DOX) is developed for cancer therapy. The hollow CaCO 3 microcapsules were prepared based on the self-assembly between chitosan and sodium alginate on CaCO 3 particles via layer-by-layer technique, and then covered with gold nanorods to obtain the microcapsule system. Upon near-infrared (NIR) irradiation, microcapsule with gold nanorods can convert the absorbed NIR light into heat. Meanwhile, doxorubicin (DOX), a chemotherapy drug, is loaded into the microcapsule system via electrostatic adsorption for combined photothermal therapy and chemotherapy. Properties of AuNR -HM-DOX including grain diameter, optical spectra were characterized. Confocal fluorescence imaging was performed to observe the morphology of the capsules and existence of DOX in the core, confirming the successful loading of DOX. The release of DOX from the capsules under continuous NIR irradiation was investigated to evaluate the temperature responsiveness of AuNR -HM-DOX. Results indicate that AuNR -HM-DOX microcapsules possess uniform particle size and high light responsiveness. The combination of chemical and physical therapy of AuNR -HM-DOX features great potential as an adjuvant therapeutic alternative material for combined cancer therapy.

scholarly journals Modeling the optical properties of a single gold nanorod for use in biomedical applications

2021 ◽  
Author(s):  
Yevgeniy Davletshin
Keyword(s):  
Optical Properties ◽  
Gold Nanorods ◽  
Biomedical Applications ◽  
Computational Models ◽  
Near Infrared ◽  
Gold Nanorod ◽  
Spatial Modulation ◽  
Element Analysis ◽  
Modulation Spectroscopy ◽  
Nir Light

Recent studies have shown that gold nanorods are highly effective agents for conversion of visible and near infrared (NIR) light into heat. Thermal therapy that utilizes this effect is called Plasmonic Photohermal Therapy (PPTT), where light absorption by photothermal agents (plasmon-resonant gold nanorods) caused kinetic energy to increase, resulting in heating of the area surrounding the agent. A primary understanding of optical and thermal properties of gold particles at nonscale level is still unclear. Due to the limitations of current equipment for nanoparticle characterization, numerical methods and computational models are widely used to understand the physic at the nanoscale. In this thesis fininte element analysis and spatial modulation spectroscopy were used to develop and test a computational model to characterize optical properties of a single gold nanorod.

scholarly journals Enhanced Delivery of Thermoresponsive Polymer-Based Medicine into Tumors by Using Heat Produced from Gold Nanorods Irradiated with Near-Infrared Light

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 5005
Author(s):  
Kohei Sano ◽  
Yumi Ishida ◽  
Toshie Tanaka ◽  
Tatsuya Mizukami ◽  
Tomono Nagayama ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Near Infrared ◽  
Drug Carrier ◽  
Light Irradiation ◽  
Infrared Light ◽  
Solution Temperature ◽  
Dependent Manner ◽  
Thermoresponsive Polymer ◽  
Tumor Bearing ◽  
Nir Light

The aim of this study was to establish a drug delivery system (DDS) for marked therapy of tumors using a thermoresponsive polymer, polyoxazoline (POZ). The effectiveness of the following was investigated: (i) the delivery of gold nanorods (GNRs) to tumor tissues, (ii) heat production of GNR upon irradiation with near-infrared (NIR) light, and (iii) high accumulation of an intravenously injected radiolabeled POZ as a drug carrier in tumors by sensing heat produced by GNRs. When the GNR solution was irradiated with NIR light (808 nm), the solution temperature was increased both in a GNR-concentration-dependent manner and in a light-dose-dependent manner. POZ, with a lower critical solution temperature of 38 °C, was aggregated depending on the heat produced by the GNR irradiated by NIR light. When it was intratumorally pre-injected into colon26-tumor-bearing mice, followed by NIR light irradiation (GNR+/Light+ group), the tumor surface temperature increased to approximately 42 °C within 5 min. Fifteen minutes after irradiation with NIR light, indium-111 (111In)-labeled POZ was intravenously injected into tumor-bearing mice, and the radioactivity distribution was evaluated. The accumulation of POZ in the tumor was significantly (approximately 4-fold) higher than that in the control groups (GNR+/without NIR light irradiation (Light–), without injection of GNR (GNR–)/Light+, and GNR–/Light– groups). Furthermore, an in vivo confocal fluorescence microscopy study, using fluorescence-labeled POZ, revealed that uptake of POZ by the tumor could be attributed to the heat produced by GNR. In conclusion, we successfully established a novel DDS in which POZ could be efficiently delivered into tumors by using the heat produced by GNR irradiated with NIR light.

scholarly journals Modeling the optical properties of a single gold nanorod for use in biomedical applications

2021 ◽  
Author(s):  
Yevgeniy Davletshin
Keyword(s):  
Optical Properties ◽  
Gold Nanorods ◽  
Biomedical Applications ◽  
Computational Models ◽  
Near Infrared ◽  
Gold Nanorod ◽  
Spatial Modulation ◽  
Element Analysis ◽  
Modulation Spectroscopy ◽  
Nir Light

Recent studies have shown that gold nanorods are highly effective agents for conversion of visible and near infrared (NIR) light into heat. Thermal therapy that utilizes this effect is called Plasmonic Photohermal Therapy (PPTT), where light absorption by photothermal agents (plasmon-resonant gold nanorods) caused kinetic energy to increase, resulting in heating of the area surrounding the agent. A primary understanding of optical and thermal properties of gold particles at nonscale level is still unclear. Due to the limitations of current equipment for nanoparticle characterization, numerical methods and computational models are widely used to understand the physic at the nanoscale. In this thesis fininte element analysis and spatial modulation spectroscopy were used to develop and test a computational model to characterize optical properties of a single gold nanorod.

Radiation Characteristics of a Particle Curtain in a Free-Falling Particle Solar Receiver

2017 ◽  
Author(s):  
Apurv Kumar ◽  
Jin-Soo Kim ◽  
Wojciech Lipiński
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Absorption Efficiency ◽  
Radiation Absorption ◽  
Particle Volume ◽  
Two Phase ◽  
Low Mass ◽  
Radiation Extinction ◽  
Solar Receiver ◽  
Free Falling

Radiation absorption by a particle curtain formed in a solar free falling particle receiver is investigated using a Eulerian-Eulerian granular two-phase model to solve the two-dimensional mass and momentum equations (CFD). The radiative transfer equation is subsequently solved by the Monte-Carlo (MC) ray-tracing technique using the CFD results to quantify the radiation intensity through the particle curtain. The CFD and MC results provide reliable opacity predictions and are validated with the experimental results available in literature. The particle curtain was found to absorb the solar radiation efficiently for smaller particles at high flowrates due to higher particle volume fraction and increased radiation extinction. However, at low mass-flowrates the absorption efficiency decreases for small and large particles.

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

2020 ◽  
Author(s):  
Alex Stafford ◽  
Dowon Ahn ◽  
Emily Raulerson ◽  
Kun-You Chung ◽  
Kaihong Sun ◽  
...  
Keyword(s):  
Near Infrared ◽  
Transient Absorption ◽  
Reaction Times ◽  
Infrared Light ◽  
Structure Property ◽  
Light Emitting ◽  
Structure Property Relationships ◽  
Nir Light ◽  
Light Intensities ◽  
Emission Quenching

Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

Transient Free Convective Flow of CNT Water Nanofluid with Heat Transfer from a Moving Cylinder

2020 ◽  
Vol 10 ◽  
Author(s):  
C. Sridevi ◽  
A. Sailakumari
Keyword(s):  
Carbon Nanotubes ◽  
Heat Generation ◽  
Convective Flow ◽  
Volume Fraction ◽  
Vertical Cylinder ◽  
Single Wall Carbon Nanotubes ◽  
Free Convective Flow ◽  
Multi Wall Carbon Nanotubes ◽  
Moving Cylinder ◽  
Variable Surface

Background: In this paper, transient two-dimensional laminar boundary layer viscous incompressible free convective flow of water based nanofluid with carbon nanotubes (CNTs) past a moving vertical cylinder with variable surface temperature is studied numerically in the presence of thermal radiation and heat generation. Methods: The prevailing partial differential equations which model the flow with initial and boundary conditions are solved by implicit finite difference method of Crank Nicolson type which is unconditionally stable and convergent. Results: Influence of Grashof number (Gr), nanoparticle volume fraction ( ), heat generation parameter (Q), temperature exponent (m), radiation parameter (N) and time (t) on velocity and temperature profiles are sketched graphically and elaborated comprehensively. Conclusion: Analysis of Nusselt number and Skin friction coefficient are also discussed numerically for both single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs).

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