Dependence of Gold Nanoparticle Radiosensitization on Functionalizing Layer Thickness

Spaas, Cedric; Dok, Rüveyda; Deschaume, Olivier; Roo, Bert De; Vervaele, Mattias; Seo, Jin Won; Bartic, Carmen; Hoet, Peter; Heuvel, Frank Van den; Nuyts, Sandra; Locquet, Jean‐Pierre

doi:10.1667/rr14207.1

Cited by 24 publications

(25 citation statements)

References 41 publications

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“…This is due to the fact that PEG and other similar molecules have densities and effective atomic masses similar to water. The reduction in radiosensitization for thicker coatings agrees with experimental observations . Simulations indicate that a denser coating of shorter PEG chains can achieve similar effects to a sparser coating of longer PEG chains .…”

Section: Discussionsupporting

confidence: 80%

“…The reduction in radiosensitization for thicker coatings agrees with experimental observations. 42 Simulations indicate that a denser coating of shorter PEG chains can achieve similar effects to a sparser coating of longer PEG chains. 43 As both density and length of a molecular coating contribute to its biological effect, a short dense coating offers improved enhancement compared to a longer less dense coating with the same biological effect.…”

Section: B Effect Of Nanoparticle Sizementioning

confidence: 93%

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Gold nanoparticle enhanced proton therapy: A Monte Carlo simulation of the effects of proton energy, nanoparticle size, coating material, and coating thickness on dose and radiolysis yield

et al. 2019

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Purpose Radiosensitizer enhanced radiotherapy provides the possibility of improved treatment outcomes by preferentially increasing the effectiveness of radiation within the tumor. Proton therapy offers improved sparing of tissue distal of the tumor along the beam path and reduced integral dose compared to conventional photon therapy. The combination of proton therapy with radiosensitizers offers the potential for an enhanced therapy with increased effect within the tumor and low integral dose. The simulations performed in this work determine the effect of nanoparticle characteristics and proton energy on the nanoscale dose and radiolysis yield enhancement for a single gold nanoparticle irradiated with a proton beam. This data can be used to determine optimal nanoparticle characteristics to enhance proton therapy. Methods A two‐stage Monte Carlo simulation was performed using Geant4. In the first stage of the simulation, the physical interactions of protons within a gold nanoparticle were modeled and the secondary electrons escaping the nanoparticle's surface were scored in a phase space file. In the second stage of the simulation, the phase space file was used as an input to model the physical interactions of the secondary electrons in water and the resulting production and chemical interactions of reactive species. By comparing a gold nanoparticle with an equivalent water nanoparticle, the nanoscale enhancement of dose and radiolysis yield was calculated. Results A large nanoscale enhancement of both the dose and radiolysis yield of up to a factor of 11 due to gold nanoparticles was found for most simulated conditions. For 50 nm gold nanoparticles, a large enhancement factor of 9–11 was observed for high proton energies; however, the enhancement was reduced for proton energies below 10 MeV. For 5 MeV incident protons, it was found that the enhancement factor was approximately 9 for gold nanoparticles of sizes 5–25 nm with a reduction in enhancement observed for nanoparticle sizes outside this range. Additionally, it was found that larger nanoparticle sizes resulted in greater total energy deposition and radiolysis yields per proton flux but with reduced efficiency per nanoparticle mass. It was observed that a large loss of enhancement occurred for thick nanoparticle coatings. However, for polyethylene glycol (PEG) coatings, coating density had a minimal effect on enhancement. Conclusions A large enhancement in dose and radiolysis yield was observed. However, the low‐energy secondary electrons produced within the gold for lower energy protons are susceptible to self‐absorption and result in the loss of enhancement observed for larger nanoparticles and thicker coatings. The radiolysis yield and dose increase with nanoparticle size; however, the yield and dose per gold mass decrease due to self‐absorption. Therefore, an intermediate nanoparticle size of approximately 10–25 nm maximizes both the radiolysis yield and dose as well as the enhancement. Coatings should be kept to the minimum effective thickness to limit ...

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Section: Discussionsupporting

confidence: 80%

Section: B Effect Of Nanoparticle Sizementioning

confidence: 93%

Gold nanoparticle enhanced proton therapy: A Monte Carlo simulation of the effects of proton energy, nanoparticle size, coating material, and coating thickness on dose and radiolysis yield

et al. 2019

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“…Spaas et al recently demonstrated that there was an average loss of 5.2% in radiosensitivity per nanometer of organic capping. 35 In our previous in vitro study, it was concluded that 10 nm PEG-Au-NPs combined to 1.3 MeV protons were more efficient in cell killing than when using lower NP diameter or higher energy protons. 21 This could be explained by the LET profiles shown in Fig.…”

Section: Discussionmentioning

confidence: 97%

“…The value first decreased with decreasing material density down to %0. 35. Hf-NP absorbed fewer electrons given its lower density and a mean electron energy comparable to heavier metals.…”

Section: A Nanoparticles Of Different Materialsmentioning

confidence: 99%

Metallic nanoparticles irradiated by low‐energy protons for radiation therapy: Are there significant physical effects to enhance the dose delivery?

et al. 2017

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“…GNPs are the most promising due to their physicochemical properties and high biocompatibility. GNPs absorb the energy of ionizing radiation and also, surface functionalization can dramatically decrease the production of radicals [3].…”

Section: Introductionmentioning

confidence: 99%

Secondary Electron Spectral Changes of Irradiated Gold Nanoparticle Caused By PEGylation

Морозов¹,

Белоусов²,

Krusanov³

et al. 2018

KEn

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Gold nanoparticles attract attention for the use in radiation therapy of tumors due to the ability to enhance the efficacy of ionizing radiation. The magnitude of the radiosensitizing effect depends on the parameters of the nanoparticle, in particular on the modification of the surface. In the present work, the spectrum of secondary particles generated in a gold nanoparticle virtually irradiated with 60 Со gamma rays as a result of surface modification by a polyethylene glycol shell was studied. The MonteCarlo calculations revealed that modification of the nanoparticle's surface changes the spectrum of secondary particles. The most robust was the loss in low-energy electrons (51%) whereas the yield of Compton electrons increased by 1.27 times. At the same time, no statistically significant changes were observed in the spectrum of secondary photons and photoelectrons. Simulation of the formation and distribution of secondary electron radiation makes it possible to evaluate the parameters important for the rational design of antitumor nanoradiosensitizers based on chemical elements with a high atomic number.

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Dependence of Gold Nanoparticle Radiosensitization on Functionalizing Layer Thickness

Cited by 24 publications

References 41 publications

Gold nanoparticle enhanced proton therapy: A Monte Carlo simulation of the effects of proton energy, nanoparticle size, coating material, and coating thickness on dose and radiolysis yield

Gold nanoparticle enhanced proton therapy: A Monte Carlo simulation of the effects of proton energy, nanoparticle size, coating material, and coating thickness on dose and radiolysis yield

Metallic nanoparticles irradiated by low‐energy protons for radiation therapy: Are there significant physical effects to enhance the dose delivery?

Secondary Electron Spectral Changes of Irradiated Gold Nanoparticle Caused By PEGylation

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