Optical properties of breast tumor phantoms containing carbon nanotubes and nanohorns

Abstract

Abstract.The degree by which optical properties of tumors are altered following introduction of carbon nanotubes (CNTs) of varying concentration and type is poorly understood, making it difficult to predict the impact of CNT inclusion on the photothermal response to laser therapies. Optical properties were measured of phantoms representative of breast tumor tissue incorporated with multiwalled carbon nanotubes (MWNTs), single-walled carbon nanotubes (SWNTs), and single-walled carbon nanohorns (SWNHs) of varying concentration (0.01-0.1 mg/ml). Tissue phantoms were made from sodium alginate (3 g/ml) incorporated with polystyrene microbeads (3 μm diam and 1 mg/ml) and talc-France powder (40 mg/ml). Absorption (μ a ) and reduced scattering (μ s ) coefficients of phantoms containing CNTs were determined by the inverse adding-doubling algorithm for the wavelength range of 400-1300 nm. Optical properties of phantoms without CNTs were in the range of μ a = 1.04-0.06 mm − 1 and μ s = 0.05-0.07 mm − 1 at a wavelength of 900 nm, which corresponds with published data for human breast tumor tissue. Incorporating MWNTs, SWNTs, and SWNHs in phantoms with a concentration of 0

Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

“…Nanocarbons, such as carbon nanotubes (CNTs) and carbon nanohorn (CNH), are considered useful in science and technology because of their remarkable physical and chemical properties, some of which might help overcome the limitations of traditional laser light technologies. In particular, nanocarbons have extraordinary photothermal energy conversion efficiency and high absorption cross-sections in a wavelength range capable of transmission within the diagnostic window (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). Although gold nanoparticles also have such photothermal properties, nanocarbons can be more effectively heated at various wavelengths because of their strong absorbance over a wide range of the optical region (38).…”

Modulated Fluorophore Signal Recovery Buried within Tissue Mimicking Phantoms

“…The absorption and reduced scattering coefficients of the skin phantoms were 0.06 mm −1 (594 nm) and 0.05 mm −1 (710 nm), and 1.8 mm −1 (594 nm) and 1.5 mm −1 (710 nm), respectively, each with standard deviations varying from ±0.02–0.08. 28 …”

“…We adopted the common assumption that a soft turbid tissue behaves as an isotropic medium, when the scattering is expressed in terms of a reduced scattering coefficient. 24, 28 The source in Equation 1 is a Gaussian beam in the vicinity of the laser focus constructed from Beer’s law as an isotropic scattering event (Equations 2 and 3). $$S_{ex}={\mu }_S^{\text{'}}·false(1-R_{sp}false)·{\varphi }_{ex0}·\text{normalexp}false(-{\mu }_t·zfalse)$$ $${\varphi }_{ex0}=I_{ex}^{\mathit{\text{amp}}}·e^{-false(\frac{x^2}{2{\sigma }_x^2}+\frac{y^2}{2{\sigma }_y^2}false)}$$ In these equations, R sp denotes the specular reflectance from the surface of the scattering medium, Φ ex0 denotes the incident fluence on the surface, µ t represents the attenuation coefficients (µ t = µ aex +µ´ s ), I amp ex is the amplitude of the Gaussian laser spot, and σ defines the excitation area dimensions.…”

“…33 Due to the absence of blood perfusion in the phantom, ω b was set to zero. The optical and thermal properties of identically prepared phantoms 28, 29 were utilized in this model…”

Chemometric determination of the length distribution of single walled carbon nanotubes through optical spectroscopy

“…For instance, the C sca /C abs ratio of gold nanospheres with radius of 10 nm under 521 nm light is only 0.01 [23]. A recent study showed that scattering from larger diameter multiple walled carbon nanotubes (MWCNTs) is minor (<8%) in light extinction over the wavelength range of 300-1300 nm [24]. Thus, it is reasonable to hypothesize that absorption spectroscopy may be an effective tool to measure the length of SWCNTs.…”