Average Physical Enhancement by Nanomaterials under X-ray Irradiation

Abstract

We for the first time used highly water soluble silica-covered gold nanoparticles (AuNP@SiO 2 ) in water to successfully isolate average physical enhancement from other enhancements such as nanoscale physical enhancement, chemical enhancement and antienhancement, and obtained the highest enhancement slope of 1.03 per weight percent (wp -1 ) and the highest experimental enhancement factor of 4.5 fold (ߝ ௫௧ =4.5; and ߝ ௫௧ = 0 for no enhancement) at 7.5 wp of gold in water. The slope and ߝ ௫௧ agree with the theoretically predicted values obtained from simulation of enhancement of X-rays by gold nanoparticles in water, and the experimental enhancement coefficient (ߛ = ߝ ௫௧ /ߝ ௧ , 0 ≤ ߛ ≤ 1) is approximately 0.90. The enhancement dependency on X-ray energy, silica layer thickness and sample thickness are studied experimentally and theoretically. The results presented here elucidate the mechanism of the average physical enhancement by nanomaterials under X-ray irradiation.KEYWORDS X-ray nanochemistry, enhancement of X-ray effect, nanomaterials, nanoscale energy deposition, physical enhancement.

Monte Carlo simulation of free radical production under keV photon irradiation of gold nanoparticle aqueous solution. Part I: Global primary chemical boost

“…While Monte Carlo (MC) simulations have widely been used to quantify this dose boost [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21], the impact of GNPs on radical species production has yet hardly been investigated. In the present study, we The small enhancement of global radical production predicted at short time by our simulations suggests that the apparent overproduction obtained experimentally using coumarin scavengers [30,33,34,35,32] arise from more complex mechanisms operating over longer time. Further studies, involving in particular chemical reactions with GNPs, need to be undertaken to better understand the experimental observations.…”

“…In solution irradiation experiments with colloidal GNPs [30,31,32,33,34,35,36] or in presence of bio-molecules [37,38,39,40,41,42] put in light the importance of the chemical stage. In particular, the use of plasmid DNA evidenced that the enhancement of DNA single strand breaks was dependent on the energy of the incident photon in the keV range [40,42], the concentration of GNPs [40], the chemical environment of the solution and in particular its scavenging ability [38,39,42], and the proximity between the GNPs and the biomolecules [38,41].…”

Surfactant‐Assisted Nanocrystalline Zinc Coordination Polymers: Controlled Particle Sizes and Synergistic Effects in Catalysis

“…The advantage of crystalline nanoscale CPs as heterogeneous catalysts is that they exhibit large specific surface areas and hold much promise for a high density of catalytically active sites and unique cooperative effects in liquid‐phase heterogeneous catalysis. Therefore, a number of strategies have been developed to control the size and shape of the crystals, including water‐in‐oil microemulsions, surfactant‐mediated hydrothermal syntheses, and high‐temperature routes . Herein, with the addition of surfactant (polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) 2000) as templates, different morphologies and particle sizes of 1 and 2 , from the bulk phase to nanoscale crystals, have been obtained through hydrothermal syntheses.…”

Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays

“…This is a clinically important radiobiological aspect because the number of GNPs per cell, N GNP , and their relative distances to the cellular targets (represented by the integration volume V cell ) are stochastic variables for a population of cells. It has to be noted that the mathematical framework of GNP-LQ could also be used in combination with other cell survival models than the LQ, for instance radiochemical models, 64 and that the computation of energy deposition may require MC simulation using specific cell geometry. [68][69][70] Finally, it has to be underlined that GNP-LQ applied to GNPT may not be directly applicable to proton/ion RT and discussing this issue is beyond the scope of this review.…”

“…For convenience, we arrange the literature according to the following order: general radiation transport aspects relevant for nanoscale simulations, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] macroscopic dose enhancement in contrast agents and dose perturbation at high-Z material interfaces, radiation transport for nanoscopic dose enhancement of GNP, [46][47][48][49][50][51][52][53][54][55][56][57][58] radiobiological and clinical aspects of GNPT, [59][60][61][62][63][64][65][66][67] application of Monte Carlo (MC) simulations to cellular environment, [68][69][70] modification of linear accelerator spectra to maximize dose enhancement 71 and GNPT using other than X-ray therapeutic beams (proton, electron). …”