Treatment Efficacy of Laser Photothermal Therapy Using Gold Nanorods: Tumor Shrinkage Study

2012 ◽  
Author(s):  
N. Manuchehrabadi ◽  
R. Toughiri ◽  
H. Cai ◽  
L. Zhu ◽  
A. Attaluri ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Laser Energy ◽  
Experimental Studies ◽  
Laser Wavelength ◽  
Measured Temperature ◽  
Laser Irradiance ◽  
Tumor Shrinkage ◽  
Wide Range ◽  
Laser Photothermal Therapy

Gold nanorods can be tuned to a specific laser wavelength and serve as strong laser energy absorbers. Due to the powerful optical absorption, the laser energy is concentrated in an area congregating by nanorods, and then the energy absorbed can be transferred to the surrounding tumor tissue by heat conduction.1–4 Previous studies have shown a wide range of heating parameters with or without temperature measurements. Our previous experiment4 has demonstrated that using only 0.1 cc gold nanorod solution can lead to tumor temperature higher than 50°C when the laser irradiance is only 2 W/cm2. Based on the measured temperature elevation and heating duration, thermal damage to the tumor is highly likely. However, some researchers raised the question whether temperature sensors used in those experimental studies are truly reflecting the temperatures in the tumors. The objective of this study is to measure quantitatively tumor shrinkage after laser irradiation to evaluate efficacy of laser photothermal therapy.

Temperature Elevations in Implanted Prostatic Tumors During Laser Photothermal Therapy Using Nanorods

2011 ◽  
Author(s):  
L. Zhu ◽  
A. Attaluri ◽  
N. Manuchehrabadi ◽  
H. Cai ◽  
R. Edziah ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Laser Energy ◽  
Laser Wavelength ◽  
Gold Nanoshells ◽  
Surrounding Tissue ◽  
Geometric Ratio ◽  
Wide Range ◽  
Laser Photothermal Therapy

Gold nanoshells or nanorods are newly developed nanotechnology in laser photothermal therapy for cancer treatments in recent years [1–10]. Gold nanoshells consists of a solid dielectric nanoparticle core (∼100 nm) coated by a thin gold shell (∼10 nm). Gold nanorods have a diameter of 10 nm and an aspect ratio of approximately four. Nanorods may be taken up by tumors more readily than nanoshells due to nanorods’ smaller size. By varying the geometric ratio, both nanoshells and nanorods can be tuned to have strong absorption and scattering to a specific laser wavelength. Among a wide range of laser wavelengths, the near infrared (NIR) laser at ∼800 nm is most attractive to clinicians due to its deep optical penetration in tissue. Therefore, the tissue would appear almost “transparent” to the 800 nm laser light before the laser reaches the nanoshells or nanorods in tumors, with minimal laser energy wasted by the tissue without the nanostructures. The laser energy absorbed in an area congregating by the nanostructures is transferred to the surrounding tissue by heat conduction. This approach not only achieves targeted delivery of laser energy to the tumor, but also maximally concentrates a majority of the laser energy to the tumor region.

MicroCT Imaging and In Vivo Temperature Elevations in Implanted Prostatic Tumors in Laser Photothermal Therapy Using Gold Nanorods

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
N. Manuchehrabadi ◽  
A. Attaluri ◽  
H. Cai ◽  
R. Edziah ◽  
E. Lalanne ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Imaging System ◽  
Laser Energy ◽  
Gold Nanorod ◽  
Laser Irradiance ◽  
Theoretical Simulation ◽  
Microct Imaging ◽  
Laser Photothermal Therapy

In this study, in vivo animal experiments are performed on implanted xenograph prostatic tumors in nude mice to investigate enhanced laser energy absorption in the tumors by an intratumoral injection of gold nanorod solutions. In vivo temperature mapping of the tumors during laser photothermal therapy has shown the feasibility of elevating tumor temperatures higher than 50 °C using only 0.1 ml nanorod solution and a low laser irradiance of 1.6 W/cm2 incident on the tumor surface. The temperature profile suggests that normal tumor tissue still absorbs some amount of the laser energy without nanorod presence; however, the injected nanorods ensure that almost all the laser energy is absorbed and confined to the targeted tumors. The inverse relationship between the temperature elevations and the tumor size implies a relatively uniform spreading of the nanorods to the entire tumor, which is also shown by microcomputed tomography (microCT) imaging analyses. The feasibility of detecting 250 OD gold nanorod solution injected to the tumors is demonstrated via a high resolution microCT imaging system. Compared to other nanostructures, the gold nanorods used in this study do not accumulate surrounding the injection site. The relatively uniform deposition of the nanorods in the tumors observed by the microCT scans can be helpful in future study in simplifying theoretical simulation of temperature elevations in tumors during laser photothermal therapy.

Thermal Effect of Gold Nanorods in Implanted Prostatic Tumors During Laser Photothermal Therapy

2012 ◽  
Author(s):  
N. Manuchehrabadi ◽  
L. Zhu ◽  
A. Attaluri ◽  
H. Cai ◽  
R. Edziah ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Systematic Approach ◽  
Thermal Damage ◽  
Tumor Tissue ◽  
Laser Energy ◽  
Laser Wavelength ◽  
Temperature Elevation ◽  
Treatment Protocols ◽  
Energy Absorbers

In recent years, nanotechnologies have emerged as promising therapies due to their ability to deliver adequate thermal dosage to irregular and/or deep-seated tumors. Gold nanorods can be tuned to a specific laser wavelength and serve as strong laser energy absorbers. Due to the powerful optical absorption, the laser energy is concentrated in an area congregating by nanorods, and then the energy absorbed can be transferred to the surrounding tumor tissue by heat conduction.1–4 Currently, there are wide variation ranges of treatment protocols using photothermal therapy. A systematic approach is lacking to analyze temperature elevation history in tumors during heating to design an optimized combination of laser parameters to maximize thermal damage to tumors.

Computational Simulation of Temperature Elevations in Tumors Using Monte Carlo Method and Comparison to Experimental Measurements in Laser Photothermal Therapy

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Navid Manuchehrabadi ◽  
Yonghui Chen ◽  
Alexander LeBrun ◽  
Ronghui Ma ◽  
Liang Zhu
Keyword(s):  
Monte Carlo ◽  
Optical Properties ◽  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Energy Deposition ◽  
Thermal Damage ◽  
Laser Energy ◽  
Simulated Temperature ◽  
Laser Energy Absorption ◽  
Laser Photothermal Therapy

Accurate simulation of temperature distribution in tumors induced by gold nanorods during laser photothermal therapy relies on precise measurements of thermal, optical, and physiological properties of the tumor with or without nanorods present. In this study, a computational Monte Carlo simulation algorithm is developed to simulate photon propagation in a spherical tumor to calculate laser energy absorption in the tumor and examine the effects of the absorption (μa) and scattering (μs) coefficients of tumors on the generated heating pattern in the tumor. The laser-generated energy deposition distribution is then incorporated into a 3D finite-element model of prostatic tumors embedded in a mouse body to simulate temperature elevations during laser photothermal therapy using gold nanorods. The simulated temperature elevations are compared with measured temperatures in PC3 prostatic tumors in our previous in vivo experimental studies to extract the optical properties of PC3 tumors containing different concentrations of gold nanorods. It has been shown that the total laser energy deposited in the tumor is dominated by μa, while both μa and μs shift the distribution of the energy deposition in the tumor. Three sets of μa and μs are extracted, representing the corresponding optical properties of PC3 tumors containing different concentrations of nanorods to laser irradiance at 808 nm wavelength. With the injection of 0.1 cc of a 250 optical density (OD) nanorod solution, the total laser energy absorption rate is increased by 30% from the case of injecting 0.1 cc of a 50 OD nanorod solution, and by 125% from the control case without nanorod injection. Based on the simulated temperature elevations in the tumor, it is likely that after heating for 15 min, permanent thermal damage occurs in the tumor injected with the 250 OD nanorod solution, while thermal damage to the control tumor and the one injected with the 50 OD nanorod solution may be incomplete.

Visualization and Quantification of Gold Nanorods Distribution in Prostatic Tumors Using MicroCT Imaging

2012 ◽  
Author(s):  
N. Manuchehrabadi ◽  
A. Attaluri ◽  
H. Cai ◽  
R. Edziah ◽  
E. Lalanne ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Cell Damage ◽  
Critical Mass ◽  
Three Dimensional ◽  
Transport Processes ◽  
Temperature Fields ◽  
Systemic Delivery ◽  
High Concentration ◽  
Laser Photothermal Therapy

One uncertainty in use of gold nanorods for laser photothermal therapy is the non-uniform spreading of gold nanorods in tissue after either systemic delivery or intratumoral injections. High concentration of gold nanorods in certain areas influences the resulted optical absorption of the laser and thermal damage to tumors. This also provides challenges in designing optimal heating protocols via modeling thermal transport in laser photothermal therapy. For successful cancer treatment, the tissue should be heated with minimum thermal dosage to induce tumor cell damage, while minimizing overheating in the surrounding healthy tissues. Thus, one of the main challenges for reliable cancer therapy is to precisely control loading and distribution of gold nanorods in the tumour tissue. The critical mass transport processes are the distribution of gold nanorods after injection to the tumor and the redistribution of gold nanorods during laser treatment. Since tumors are opaque, nanostructure distribution in tissue is often studied either by theoretical modeling approaches1, or via dye enhanced imaging on superficial layers of tumors.2 It is important to find a technique which can directly visualize and analyze three-dimensional nanostructure distribution of tumors. Three-dimensional reconstructions of tumors with the ability to trace gold nanorod spreading have the potential for precise theoretical simulation of temperature fields. Previous studies showed that computer tomography (CT) scan is a promising technique to be utilized to characterize the distribution of intratumorally injected magnetic nanoparticles in tumors 3.

A NUMERICAL SIMULATION OF CONVECTIVE FLOW IN THE SOLIDIFICATION PROCESS

2011 ◽  
Vol 08 (01) ◽  
pp. 1-17 ◽  
Author(s):  
ABDEL ILLAH NABIL KORTI
Keyword(s):  
Natural Convection ◽  
Practical Importance ◽  
Experimental Studies ◽  
Solidification Process ◽  
Numerical Approach ◽  
Mushy Region ◽  
Convection Flow ◽  
Measured Temperature ◽  
Wide Range

There has been a growing research interest in the melting and solidification technology among mathematicians and engineers. The topic has obvious practical importance in a wide range of applications. Natural convection may play a significant role in heat transfer and hence affect the progress of the solidification. A fixed-grid finite volume numerical approach is developed and used to simulate physical details of convection flow in the solidification problems. This approach is based on the enthalpy–porosity method that is traditionally used to track the motion of the liquid–solid front and to obtain the temperature distribution and the velocity profiles in the liquid phase. The enthalpy–porosity model treats the mushy region as a porous medium. In this paper, the numerical and experimental studies of unsteady natural convection during solidification of cylindrical ingots are presented. The aim of the study consists of the numerical determination of the fluid flow, the temperature evolution, and the solidification front versus time. To validate the numerical model, an experimental study of the simple casting of cylindrical ingots was undertaken within the laboratory of metallurgy. The measured temperature was compared with values calculated numerically. A good agreement was obtained.

Theoretical Simulation of Temperature Elevations in Tumors Using Monte Carlo Method and Comparison to Experimental Measurements During Laser Photothermal Therapy

2013 ◽  
Author(s):  
Navid Manuchehrabadi ◽  
Yonghui Chen ◽  
Alexander LeBrun ◽  
Ronghui Ma ◽  
Liang Zhu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Treatment Protocol ◽  
Gold Nanorod ◽  
Theoretical Simulation ◽  
The Past ◽  
Geometric Ratio ◽  
Laser Photothermal Therapy

Nanotechnology using gold nanoshells or nanorods is a newly developed hyperthermia approach and has been tested in the past several years in cancer treatment.1–2 Gold nanorods have a diameter of ∼10 nm and an aspect ratio of approximately four. By varying the geometric ratio, the nanostructures can be tuned to have strong absorption and scattering to a specific laser wavelength. Designing an optimal treatment protocol of laser photothermal therapy requires understanding of gold nanorod deposition inside the tumor after injection, its resulted specific absorption rate (SAR) distribution, and the ultimate temperature field in the tumor during the treatment. Recent microCT studies by our group have suggested that the gold nanorod solution injected into PC3 prostatic tumors results in an almost uniform distribution of the gold nanorods in the tumors.3 The Monte Carlo method has been used in the past to determine the heating pattern (SAR) of laser-tissue thermal interaction.4 However, the accuracy of the theoretical simulation of the temperature fields in tumors relies on precise measurements of the optical properties of the tumors with nanorods presence.

Treatment efficacy of laser photothermal therapy using gold nanorods

2013 ◽  
Vol 12 (2) ◽  
pp. 157 ◽  
Author(s):  
Navid Manuchehrabadi ◽  
Raheleh Toughiri ◽  
Charles Bieberich ◽  
Hong Cai ◽  
Anilchandra Attaluri ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Treatment Efficacy ◽  
Photothermal Therapy ◽  
Laser Photothermal Therapy

Human Induced Pluripotent Stem Cells for Tumor Targeted Delivery of Gold Nanorods and Enhanced Photothermal Therapy

ACS Nano ◽  
2016 ◽  
Vol 10 (2) ◽  
pp. 2375-2385 ◽  
Author(s):  
Yanlei Liu ◽  
Meng Yang ◽  
Jingpu Zhang ◽  
Xiao Zhi ◽  
Chao Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Gold Nanorods ◽  
Pluripotent Stem Cells ◽  
Targeted Delivery ◽  
Photothermal Therapy ◽  
Induced Pluripotent
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