Secondary Electron Spectral Changes of Irradiated Gold Nanoparticle Caused By PEGylation

Морозов, В. Н.; Белоусов, А. В.; Krusanov, G. A.; Колыванова, М. А.; Chernyaev, A. P.; Shtil, Alexander А.

doi:10.18502/ken.v3i2.1822

Cited by 4 publications

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References 4 publications

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“…Within the uncertainties of the present experiment, it may also be reasonably applicable at lower electron energies, although caution should be taken when considering different coating thicknesses or materials (or even a coating plus conjugated biomolecules). A study by Morozov et al [56] showed a 51% suppression of low-energy electrons in the energy range below 3 keV for a PEG coating thickness of 8.5 nm. This thickness is comparatively large compared to the values reported in the review by Kuncic and Lacombe [6].…”

Section: Use Of the Results For Benchmarkingmentioning

confidence: 98%

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part I: Experiment and raw data analysis

et al. 2023

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Electron emission spectra of gold nanoparticles (AuNPs) after photon interaction were measured over the energy range between 50 eV and 9500 eV to provide reference data for Monte Carlo radiation-transport simulations. Experiments were performed with the HAXPES spectrometer at the PETRA III high-brilliance beamline P22 at DESY (Hamburg, Germany) for photon energies below and above each of the gold L-edges, that is, at 11.9 keV, 12.0 keV, 13.7 keV, 13.8 keV, 14.3 keV, and 14.4 keV. The study focused on a sample with gold nanoparticles with an average diameter of 11.0 nm on a thin carbon foil. Additional measurements were performed on a sample with 5.3 nm gold nanoparticles and on reference samples of gold and carbon foils. Further measurements were made to calibrate the photon flux monitor, to characterize the transmission function of the electron spectrometer, and to determine the size of the photon beam. This allowed the determination of the absolute values of the spectral particle radiance of secondary electrons per incident photon flux. The paper presents the experimental and raw data analysis procedures, reviews the data obtained for the nanoparticle samples, and discusses their limitations.

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Section: Use Of the Results For Benchmarkingmentioning

confidence: 98%

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part I: Experiment and raw data analysis

et al. 2023

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Monte Carlo model for evaluation of concentration of gold nanoparticle clusters as predictor of effective dose in proton therapy of microscopic tumors

Alanazi

Akhdar

et al. 2022

AIP Advances

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Radio-sensitization with gold nanoparticles (GNPs) is a relatively recent advancement of radiotherapy that is determined to increase radiation in the target tumor region. Monte Carlo (MC) simulation is a well-known method that has gained popularity by assisting in determining the effective dose in various tumors. Assessing the concentration of particles during proton therapy can provide the key to evaluating the efficiency of the performed treatment. Therefore, this study aimed to investigate the interconnection between the concentration of gold nanoparticle clusters and the dose enhancement in microscopic tumors by using the MC Model. A single cell tumor model with a size of 5 μm that was exposed to 100 MeV protons in a region resembling the human brain was investigated by using an MC simulation employing the Geant4 toolkit. With each nanoparticle having a diameter of 15 nm, a three-dimensional model of the random distribution of gold nanoparticle clusters was developed. Then, the dose enhancement for various concentrations of the GNPs accumulated around the tumor was estimated according to the dose enhancement factor (DEF), while the dose was concentrated on the surface of each GNP in the clusters. The results showed that the dose enhancement located at the Bragg-peak in the tumor region depended on the different concentrations of the GNPs. DEF values were found to be 1.016, 1.022, 1.026, 1.035, 1.013, 1.000, and 0.984 for the 1, 2, 3, 5, 10, 30, and 50 mg/ml concentration levels in water, respectively. The findings also revealed that large GNP clusters with high concentration levels yield larger DEFs than clusters with lower concentration levels, which may have an impact on radiation therapy. Specifically, at a concentration higher than 10 mg/ml, the estimated dose was significantly lower than those for a concentration of 5 mg/ml by about ∼100 mGy. As the benefit of the increased total dose must be balanced against the effect of the accumulation of nanoparticles, the current study detected dose reduction in regions that accumulate GNPs at high concentrations. As a result, the potential efficiency of the radiotherapeutic treatment can be reduced.

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Radial dependence of ionization clustering around a gold nanoparticle irradiated by X-rays under charged particle equilibrium

Thomas,

Schwarze,

Rabus

2024

Phys. Med. Biol.

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Objective: This work explores the enhancement of ionization clustering and its radial dependence around a gold nanoparticle (NP), indicative of the induction of DNA lesions, a potential trigger for cell-death.Approach: Monte Carlo track structure simulations were performed to determine (a) the spectral fluence of incident photons and electrons in water around a gold NP under charged particle equilibrium conditions and (b) the density of ionization clusters produced on average as well as conditional on the occurrence of at east one interaction in the nanoparticle using Associated Volume Clustering. Absorbed dose was determined for comparison with a recent benchmark intercomparison. Reported quantities are normalized to primary fluence, allowing to establish a connection to macroscopic dosimetric quantities.Main results: The modification of the electron spectral fluence by the gold NP is minor and mainly occurs at low energies. The net fluence of electrons emitted from the NP is dominated by electrons resulting from photon interactions. Similar to the known dose enhancement, increased ionization clustering islimited to a distance from the NP surface of up to 200 nm. The number of clusters per energy imparted is increased at distances of up to 150nm, and accordingly the enhancement in clustering notably surpasses that of dose enhancement. Smaller NPs cause noticeable peaks in the conditional frequency of clusters between 50 nm to 100 nm from the NP surface. Significance: This work shows that low energy electrons emitted by nanoparticles lead to an increase of ionization clustering in their vicinity exceeding that of energy imparted. While the electron component of the radiation field plays an important role in determining the background contribution to ionization clustering and energy imparted, the dosimetric effects of nanoparticles are governed by the interplay of secondary electron production by photon interaction and their ability to leave the nanoparticle.

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Secondary Electron Spectral Changes of Irradiated Gold Nanoparticle Caused By PEGylation

Cited by 4 publications

References 4 publications

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part I: Experiment and raw data analysis

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part I: Experiment and raw data analysis

Monte Carlo model for evaluation of concentration of gold nanoparticle clusters as predictor of effective dose in proton therapy of microscopic tumors

Radial dependence of ionization clustering around a gold nanoparticle irradiated by X-rays under charged particle equilibrium

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