Probing nanoantenna-directed photothermal destruction of tumors using noninvasive laser irradiation

Abstract

Plasmonic nanomaterials have tremendous potential to improve the tumor specificity of traditional cancer ablation practices, yet little effort has been directed toward quantitatively understanding their photothermal energy conversion in tumor tissues. In the present work, we develop a predictive model for plasmonic nanomaterial assisted tumor destruction under extracorporeal laser irradiation. Instead of appealing to heuristically based laser intensification models with tunable, tissue absorption and scattering coefficients, we consider fundamental characteristics of optoelectrothermal energy conversion and heat dissipation for plasmonic nanomaterials within living tumor tissues to construct a simulation tool that accurately reproduces our experimental findings, including aspects of delayed time-temperature characteristics. We believe the comprehensive modeling strategy outlined here provides a groundwork for the development of anticipatory therapeutic planning tools with individually tailored treatment plans, resulting in an ultimate benefit to ailing cancer patients. © 2009 American Institute of Physics. ͓doi:10.1063/1.3271522͔The use of plasmonic nanomaterials in photothermal therapy of tumors has received increasing attention over the past few years, 1-9 primarily because of the directivity, specificity, and nonintrusive nature of the underlying treatment protocol. Tumor-targeted nanoantennas are ideally suited for many of these applications. These nanoantennas exploit the geometrically tunable surface plasmon resonance ͑SPR͒ phenomenon of metal nanoparticles, whereby external electromagnetic fields can induce the resonant oscillation of nanoparticle free electrons and allow efficient photothermal conversion of the nonradiative extinction component to heat through electron-electron and electron-phonon relaxation mechanisms. 2-9 Further, surface-modification of nanostructured plasmonic materials with polymers and targeting ligands has enabled those to evade rapid clearance from the blood stream and intravenously target tumors via unique biological tumor characteristics, thereby enabling highly specific heating of tumor cells under laser irradiation with wavelengths overlapping the nanoparticle SPR absorption regime. [2][3][4][5][6][7][8][9] While preclinical tests with tumor-targeted nanoantennas have produced impressive results, 10 few efforts have been made to quantitatively model and predict four-dimensional temperature gradients 11 in tumors and neighboring tissues. Previously, we developed a photothermal heating model where, on system spatiotemporal scales, the details of nanoantenna energy conversion were abstracted with predefined tuning parameters prescribed in terms of macroscopic tissue absorption and scattering coefficients, 12 with an intention of mimicking the underlying microscale interactions in an upscaled physical limit by appealing to the gross consequences of the pertinent photothermal interactions. Such considerations, however, are not physically complete in nature, since the thermophysica...

Investigation of thermal damage of tissues embedded with large blood vessels during plasmonic photo-thermal heating (PPTH)

“…However, the tissue transmissivity is highest in the near infrared (NIR) spectral range of 750-1,100 nm (Tuan, 2003), and is known as therapeutic window. Over last 30 years laser have been extensively used as a therapeutic tool (Welch, 1984;Yang et al, 1990;LeCarpentier et al, 1989LeCarpentier et al, , 1993Chen et al, 1994;DasGupta et al, 2009;Ghosh et al, 2014) to destroy malignant cells. These studies have given an insight to the penetration of laser light into the bio-tissue and the obtained thermal history both numerically and experimentally.…”

“…The tissue ablation has been characterized by progressive growth of a surface dehydration zone, surface deformation, etc. DasGupta et al (2009) developed a predictive model to calculate the tumor temperature during plasmonic gold nanorod mediated photo-thermal therapy. Recently, we (Paul et al, 2014b) have developed a computational model to predict the efficacy of intratumoral injection of gold nanorods during photo-thermal therapy.…”

Impedance Matching Analysis of Cylindrical Plasmonic Nanoantennas Fed by Optical Transmission Lines

“…The development in nanoantenna theory has also been increased due the important applications in different fields [17][18][19][20][21][22][23][24][25][26][27][28]. For example, the ability of metal nanoparticles to confine and enhance optical fields in nanometre regions is used in high-resolution microscopy, where fluorescence emission from a single molecule can be strongly enhanced [17][18][19][20][21][22].…”

“…Also, this radiation of a single emitter can be highly directed by nanoantenna arrays [23]. Other important applications are in nanobioimaging to analyse biological process [24], plasmonic photovoltaic cells [25], treatment of cancer in medicine [26], use of wireless at a nanoscale [27], plasmonic laser and optical data storage [28], and sub-wavelength integrated optical circuit [29]. In this work, we focus on the last application.…”

Endothelial Thermotolerance Impairs Nanoparticle Transport in Tumors

“…[21-27] Plasmonic nanomaterials efficiently convert near-infrared light into localized heat due to rapid oscillations in the nanoparticle's electron cloud, an effect known as surface plasmon resonance (SPR). [28, 29]…”