Nanophotothermolysis of multiple scattered cancer cells with carbon nanotubes guided by time-resolved infrared thermal imaging
University of Arkansas at Little Rock, Applied Science Department, Nanotechnology Center, Little Rock, Arkansas 72204, USA. Journal of Biomedical Optics
(Impact Factor: 2.86).
01/2009; 14(2):021007. DOI: 10.1117/1.3119135
Nanophotothermolysis with long laser pulses for treatment of scattered cancer cells and their clusters is introduced with the main focus on real-time monitoring of temperature dynamics inside and around individual cancer cells labeled with carbon nanotubes. This technique utilizes advanced time- and spatially-resolved thermal radiometry imaging for the visualization of laser-induced temperature distribution in multiple-point absorbing targets. The capability of this approach was demonstrated for monitoring of thermal effects under long laser exposure (from millisecond to seconds, wavelength 1,064 nm, maximum power 1 W) of cervical cancer HeLa cells labeled with carbon nanotubes in vitro. The applications are discussed with a focus on the nanophotothermolysis of small tumors, tumor margins, or micrometastases under the guidance of near-IR and microwave radiometry.
Available from: Ravi Singh
- "However, nano or picosecond pulsed lasers are not commonly available in clinical environments, and there are virtually no reports of in vivo cancer therapy studies with this approach. We and others previously have shown that MWCNTs are effective near infrared radiation (NIR) transducers for laser-induced thermal therapy, allowing greater heat generation and localization within a tumor target than laser irradiation alone (Biris et al 2009, Dai et al 2005, Ding et al 2011, Fisher et al 2010, Burke et al 2009). Here, we extend these findings through the use of magnetic resonance imaging (MRI) thermography to demonstrate that for a fixed concentration of nanoparticles and a fixed laser energy input, the use of a higher power and a shorter duration laser pulse leads to a greater peak temperature and improved localization of the temperature field than a longer duration, lower power pulse. "
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ABSTRACT: Focusing heat delivery while minimizing collateral damage to normal tissues is essential for successful nanoparticle-mediated laser-induced thermal cancer therapy. We present thermal maps obtained via magnetic resonance imaging characterizing laser heating of a phantom tissue containing a multiwalled carbon nanotube inclusion. The data demonstrate that heating continuously over tens of seconds leads to poor localization (∼ 0.5 cm) of the elevated temperature region. By contrast, for the same energy input, heat localization can be reduced to the millimeter rather than centimeter range by increasing the laser power and shortening the pulse duration. The experimental data can be well understood within a simple diffusive heat conduction model. Analysis of the model indicates that to achieve 1 mm or better resolution, heating pulses of ∼2 s or less need to be used with appropriately higher heating power. Modeling these data using a diffusive heat conduction analysis predicts parameters for optimal targeted delivery of heat for ablative therapy.
Available from: Kobi Jakobsohn
- "In addition to research regarding early detection of cancer, gold nanorods have been utilized as photothermal therapy-mediated agents. In these studies, the absorption properties of gold nanorods in the surface plasmon resonance wavelength are used to elevate temperature to 50°C and above, usually using lasers with a high optical output (above 10 W/cm2 for about 20 minutes) in order to achieve effective denaturation and coagulation of cellular proteins, as well as cell death.11,12,20,21 "
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ABSTRACT: One of the critical problems in cancer management is local recurrence of disease. Between 20% and 30% of patients who undergo tumor resection surgery require reoperation due to incomplete excision. Currently, there are no validated methods for intraoperative tumor margin detection. In the present work, we demonstrate the potential use of gold nanoparticles (GNPs) as a novel contrast agent for photothermal molecular imaging of cancer.
Phantoms containing different concentrations of GNPs were irradiated with continuous-wave laser and measured with a thermal imaging camera which detected the temperature field of the irradiated phantoms.
The results clearly demonstrate the ability to distinguish between cancerous cells specifically targeted with GNPs and normal cells. This technique, which allows highly sensitive discrimination between adjacent low GNP concentrations, will allow tumor margin detection while the temperature increases by only a few degrees Celsius (for GNPs in relevant biological concentrations).
We expect this real-time intraoperative imaging technique to assist surgeons in determining clear tumor margins and to maximize the extent of tumor resection while sparing normal background tissue.
Available from: Alexey N. Bashkatov
- "For example, there are the indocyanine green activated by irradiation of an infrared diode laser  , the methylene blue activated in red spectral range , the hematoporphyrin and chlorin derivatives , and many others photosensitizers. Carbon nanotubes are recognized as effective agents and used, for instance, for cancer cells labeling during the nanophotothermolysis with long laser pulses . "
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ABSTRACT: In this paper we have studied effect of a hyperosmotic optical clearing
agent (OCA), such as polyethylene glycol, on the fluorescence intensity
from a target located in subcutaneous area in the model experiments. As
a fluorescence agent the nanocomposite including gold nanorods with
hematophorphyrin was used. The remitted fluorescent signal traveling to
the tissue surface was monitored over time as the tissue was treated
with the OCA. The detected fluorescent signal increased as the
scattering in tissue samples was substantially reduced. The study has
shown how OCA can be used to improve the detected signal at localization
of subcutaneous target tissue at the photothermal or photodynamic
therapy. Immersion clearing of skin can be also useful for improvement
of laser exposure efficiency due to the increasing of light penetration
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