A method for evaluating the role of gold nanoparticles in monochromatic x-ray studies

Abstract

To promote the use of gold nanoparticles as an enhancement agent from a principle concept into therapeutic applications, it is imperative to obtain detailed knowledge of the nanoparticle-induced radiobiological mechanisms. Synchrotrons are the preferred x-ray source when conducting systematic investigations regarding the role of gold nanoparticles in radiation therapy. The primary objective motivating this dissertation was to circumvent existing limitations at the interface between synchrotron science and cell biology. The phenomenon that inspired this goal is the observation that gold nanoparticles mediate the behavior of cells maintained under deviated environmental culture conditions. To accomplish this cross-disciplinary achievement, each part of the experiment process is critically reviewed and reassessed. The viability assessment based on the conversion of the tetrazolium salt MTT (3-(4,5-dimethylthiazol-2)-2,5-diphenyltetrazolium bromide) is modified to quantify the number of viable cells in the irradiation vessel. The established concept for horizontal irradiations enables the treatment of the living cells maintained under optimal cell line-specific culture conditions at synchrotron beamlines. The introduced sample transportation strategy completes the procedure, which is finally characterized by a minimized number of experimental parameters. By allowing living cells to proliferate uninterrupted and undisturbed throughout the experiment, the established method generates reliable and meaningful results that reflect the true cellular response to monochromatic keV x-rays. The presented gold nanoparticle study illustrates that the otherwise mediating nanoparticles do not enhance the radiotherapeutic effectiveness of monochromatic 20.0 keV x-rays. The implication is that the presented method is capable of elevating the acceptance and credibility of all subsequent synchrotron-based studies on living cells. Ideas for future research include the development of live-cell imaging applications at synchrotron beamlines.