Jon Whitney

Long-term survival following a single treatment of kidney tumors with multiwalled carbon nanotubes and near-infrared radiation

Multiwalled carbon nanotubes (MWCNTs) exhibit physical properties that render them ideal candidates for application as noninvasive mediators of photothermal cancer ablation. Here, we demonstrate that use of MWCNTs to generate heat in response to near-infrared radiation (NIR) results in thermal destruction of kidney cancer in vitro and in vivo. We document the thermal effects of the therapy through magnetic resonance temperature-mapping and heat shock protein-reactive immunohistochemistry. Our results demonstrate that use of MWCNTs enables ablation of tumors with low laser powers (3 W/cm2) and very short treatment times (a single 30-sec treatment) with minimal local toxicity and no evident systemic toxicity. These treatment parameters resulted in complete ablation of tumors and a >3.5-month durable remission in 80% of mice treated with 100 μg of MWCNT. Use of MWCNTs with NIR may be effective in anticancer therapy.

Photothermal Response of Human and Murine Cancer Cells to Multiwalled Carbon Nanotubes after Laser Irradiation

This study demonstrates the capability of multiwalled carbon nanotubes (MWNTs) coupled with laser irradiation to enhance treatment of cancer cells through enhanced and more controlled thermal deposition, increased tumor injury, and diminished heat shock protein (HSP) expression. We also explored the potential promise of MWNTs as drug delivery agents by observing the degree of intracellular uptake of these nanoparticles. To determine the heat generation capability of MWNTs, the absorption spectra and temperature rise during heating were measured. Higher optical absorption was observed for MWNTs in water compared with water alone. For identical laser parameters, MWNT-containing samples produced a significantly greater temperature elevation compared to samples treated with laser alone. Human prostate cancer (PC3) and murine renal carcinoma (RENCA) cells were irradiated with a 1,064-nm laser with an irradiance of 15.3 W/cm(2) for 2 heating durations (1.5 and 5 minutes) alone or in combination with MWNT inclusion. Cytotoxicity and HSP expression following laser heating was used to determine the efficacy of laser treatment alone or in combination with MWNTs. No toxicity was observed for MWNTs alone. Inclusion of MWNTs dramatically decreased cell viability and HSP expression when combined with laser irradiation. MWNT cell internalization was measured using fluorescence and transmission electron microscopy following incubation of MWNTs with cells. With increasing incubation duration, a greater number of MWNTs were observed in cellular vacuoles and nuclei. These findings offer an initial proof of concept for the application of MWNTs in cancer therapy.

Pre-osteoblast infiltration and differentiation in highly porous apatite-coated PLLA electrospun scaffolds

Electrospun polymer/apatite composite scaffolds are promising candidates as functional bone substitutes because of their ability to allow pre-osteoblast attachment, proliferation, and differentiation. However these structures usually lack an adequate pore size to permit sufficient cell migration and colonization of the scaffold. To overcome this limitation, we developed an apatite-coated electrospun PLLA scaffold with varying pore size and porosity by utilizing a three-step water-soluble PEO fiber inclusion, dissolution, and mineralization process. The temporal and spatial dynamics of cell migration into the scaffolds were quantified to determine the effects of enhanced pore size and porosity on cell infiltration. MC3T3-E1 pre-osteoblast migration into the scaffolds was found to be a function of both initial PEO content and time. Scaffolds with greater initial PEO content (50% and 75% PEO) had drastically accelerated cell infiltration in addition to enhanced cell distribution throughout the scaffold when compared to scaffolds with lower PEO content (0% and 25% PEO). Furthermore, scaffolds with an apatite substrate significantly upregulated MC3T3-E1 alkaline phosphatase activity, osteocalcin content, and cell-mediated mineralization as compared to PLLA alone. These findings suggest that such a scaffold enhances pre-osteoblast infiltration, colonization, and maturation in vitro and may lead to overall improved bone formation when implanted in vivo.

Single walled carbon nanohorns as photothermal cancer agents.

Nanoparticles have significant potential as selective photo‐absorbing agents for laser based cancer treatment. This study investigates the use of single walled carbon nanohorns (SWNHs) as thermal enhancers when excited by near infrared (NIR) light for tumor cell destruction.

Heat shock protein expression and temperature distribution in prostate tumours treated with laser irradiation and nanoshells

Purpose: Sub-lethal temperature elevations in the tumour incurred during laser cancer therapy can induce heat shock protein (HSP) expression leading to enhanced tumour survival and recurrence. Nanoshells utilised in combination with laser therapy can potentially enable selective heat deposition, greater thermal injury, and diminished HSP expression in the tumour. The study objective was to measure the distribution of temperature and HSP expression in prostate tumours in response to laser therapy alone or with nanoshells to determine if these combinatorial therapies can minimise HSP expression. Methods: PC3 cells were inoculated in the backs of CB17-Prkd c SCID/J mice and treated with external laser irradiation (wavelength of 810 nm, irradiance of 5 W/cm2, spot size of 5 mm, and heating duration of 3 min) alone or in combination with gold nanoshells (diameter of 55 nm and outer gold shell thickness of 10 nm) introduced into the tumour 24 h prior to laser treatment. Magnetic resonance temperature imaging was used to measure the distribution of temperature elevation in the tumours during laser treatment. Tumours were sectioned 16 h following laser treatment, stained for Hsp27 and Hsp70, imaged with a confocal microscope, and HSP expression levels were quantified as a function of depth in the tumours. Results: Maximum temperature elevations at the tumour surface were 28°C for laser treatment only and 50°C for laser heating in combination with gold nanoshells. Laser therapy alone caused significant induction of HSP expression in the first few millimeters of the tumour depth, whereas decreasing HSP expression occurred with greater tumour depth. Tumours treated with laser and nanoshells experienced substantial temperatures (73–78°C) at the tumour surface and temperatures greater than 53°C in the first few millimeters which eliminated HSP expression. Conclusion: Inclusion of nanoshells in laser therapy can provide a mechanism for enhancing heat deposition capable of eliminating HSP expression within a larger tumour region compared to laser heating alone.

Spatial and temporal measurements of temperature and cell viability in response to nanoparticle-mediated photothermal therapy

AIM Nanoparticle-enhanced photothermal therapy is a promising alternative to tumor resection. However, quantitative measurements of cellular response to these treatments are limited. This article introduces a Bimodal Enhanced Analysis of Spatiotemporal Temperature (BEAST) algorithm to rapidly determine the viability of cancer cells in vitro following photothermal therapy alone or in combination with nanoparticles. MATERIALS & METHODS To illustrate the capability of the BEAST viability algorithm, single wall carbon nanohorns were added to renal cancer (RENCA) cells in vitro and time-dependent spatial temperature maps measured with an infrared camera during laser therapy were correlated with post-treatment cell viability distribution maps obtained by cell-staining fluorescent microscopy. CONCLUSION The BEAST viability algorithm accurately and rapidly determined the cell viability as a function of time, space and temperature.

Arrhenius parameter determination as a function of heating method and cellular microenvironment based on spatial cell viability analysis

Abstract Purpose: Predictions of injury in response to photothermal therapy in vivo are frequently made using Arrhenius parameters obtained from cell monolayers exposed to laser or water bath heating. However, the impact of different heating methods and cellular microenvironments on Arrhenius predictions has not been thoroughly investigated. This study determined the influence of heating method (water bath and laser irradiation) and cellular microenvironment (cell monolayers and tissue phantoms) on Arrhenius parameters and spatial viability. Methods: MDA-MB-231 cells seeded in monolayers and sodium alginate phantoms were heated with a water bath for 3–20 min at 46, 50, and 54 °C or laser irradiated (wavelength of 1064 nm and fluences of 40 W/cm2 or 3.8 W/cm2 for 0–4 min) in combination with photoabsorptive carbon nanohorns. Spatial viability was measured using digital image analysis of cells stained with calcein AM and propidium iodide and used to determine Arrhenius parameters. The influence of microenvironment and heating method on Arrhenius parameters and capability of parameters derived from more simplistic experimental conditions (e.g. water bath heating of monolayers) to predict more physiologically relevant systems (e.g. laser heating of phantoms) were assessed. Results: Arrhenius predictions of the treated area (<1% viable) under-predicted the measured areas in photothermally treated phantoms by 23 mm2 using water bath treated cell monolayer parameters, 26 mm2 using water bath treated phantom parameters, 27 mm2 using photothermally treated monolayer parameters, and 0.7 mm2 using photothermally treated phantom parameters. Conclusions: Heating method and cellular microenvironment influenced Arrhenius parameters, with heating method having the greater impact.

Spatiotemporal Temperature and Cell Viability Measurement Following Laser Therapy in Combination With Carbon Nanohorns

Cancer remains one of the most deadly diseases today. Laser-induced photothermal therapy can provide a minimally invasive treatment alternative to surgical resection. The selectivity and effectiveness of laser therapy can be greatly enhanced when photoabsorbing nanoparticles such as nanoshells, single walled carbon nanotubes, multi-walled carbon nanotubes, or single wall carbon nanohorns (SWNHs) are introduced into the tissue. Prior studies have effectively used SWNHs combined with near infrared (NIR) laser light to target and destroy microbes [1]. We have previously reported increased tumor cell destruction when SWNHs were used in combination with laser therapy. The present work provides more extensive characterization of cell viability in response to laser therapy alone or in combination with SWNHs. Furthermore, the spatiotemporal temperature and cell viability in vitro in response to combinatorial SWNH-mediated laser therapies is determined using infrared thermometry and a novel viability algorithm, respectively. These new measurements will be critical for planning SWNH-mediated laser treatments where knowledge of the geometric distribution of temperature and cell death are critical to achieving the goal of selectively eliminating a tumor with specific spatial margins with minimal damage to surrounding healthy tissue.© 2010 ASME

Spatial Measurement of Viability in Tissue Phantoms and Ex Vivo Bladder Tissue in Response to Photothermal Therapy and Single Walled Carbon Nanohorns

Cancer is one of the most deadly diseases and leading cause of death. Laser based photothermal therapy can provide a minimally invasive alternative to surgical resection. The selectivity and effectiveness of laser therapy can be greatly enhanced when photoabsorbing nanoparticles such as nanoshells, single walled carbon nanotubes, multi-walled carbon nanotubes, or single wall carbon nanohorns (SWNHs) are introduced into the tissue[1]. Quantitative methods for measuring tumor response to nanoparticle enhanced laser therapies are critical for determining appropriate laser parameters and nanoparticle properties needed to achieve maximum therapeutic benefit. We have previously reported a new method for measuring two dimensional (2D) spatial viability distributions in cell monolayers in response to laser irradiation and nanoparticles. This method has been refined to allow determination of cell viability in three dimensions (3D) within a more physiologically representative tumor volume. This refined method was used to determine the viability of breast cancer cells suspended within sodium alginate tissue phantoms following treatment with SWNHs and external laser irradiation. The tumor treatment volume was accurately quantified in response to varying laser treatment parameters and nanoparticle concentrations. Spatial cellular viability was also measured in ex vivo pig bladders in response to SWNHs and laser irradiation to provide a more anatomically relevant environment. These new measurement methods enable quantification of spatial viability and therapeutic effectiveness, using 3D tumor environments which are more representative than cell monolayers.Copyright

Computational Models and Digital Image Analysis of Carbon Nanotube Mediated Laser Cancer Therapy

Laser-based photothermal therapy can provide a minimally invasive treatment alternative to surgical resection of tumors. The selectivity and effectiveness of laser therapy can be greatly enhanced when photo-absorbing nanoparticles such as multi-walled carbon nanotubes (MWNTs) are introduced into the tissue [1,2]. The effectiveness of nanoparticle enhanced laser treatment can be determined through a combined approach using experimental measurement and computational models. This approach allows ideal laser parameters (e.g. irradiance, pulse duration) and nanoparticle properties (e.g. concentration and delivery method) to be selected to maximize treatment efficacy. We developed a computational model to predict the temperature response of tissue representative phantoms and in vivo murine renal cancer (RENCA) kidney tumors to MWNTs used in combination with external laser irradiation. The accuracy of the computational model prediction of temperature was verified by comparing with experimental measurements of temperature using magnetic resonance thermometry (MRTI). In addition, an image analysis technique is introduced for measuring the spatial viability of cancer cells suspended in tissue phantoms following nanoparticle enhanced laser therapy and correlating cell viability with thermal exposure. Spatial viability and thermal measurements are combined to predict cell death as a function of temperature in tissue phantoms.Copyright