RESUMEN
As well as being a significant source of environmental radiation exposure, α-particles are increasingly considered for use in targeted radiation therapy. A better understanding of α-particle induced damage at the DNA scale can be achieved by following their tracks in real-time in targeted living cells. Focused α-particle microbeams can facilitate this but, due to their low energy (up to a few MeV) and limited range, α-particles detection, delivery, and follow-up observations of radiation-induced damage remain difficult. In this study, we developed a thin Boron-doped Nano-Crystalline Diamond membrane that allows reliable single α-particles detection and single cell irradiation with negligible beam scattering. The radiation-induced responses of single 3 MeV α-particles delivered with focused microbeam are visualized in situ over thirty minutes after irradiation by the accumulation of the GFP-tagged RNF8 protein at DNA damaged sites.
Asunto(s)
Partículas alfa , Daño del ADN/efectos de la radiación , Proteínas de Unión al ADN/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Partículas alfa/efectos adversos , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Genes Reporteros , Histonas/metabolismo , Humanos , Membranas Artificiales , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Imagen de Lapso de Tiempo , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
We describe a new approach for the detection and identification of actinides at low activity levels directly in aqueous solution. The measurement consists initially, in immobilizing alpha emitters in the form of insoluble hydroxides onto the entrance window of an immersed alpha particles detector. For this, a boron doped diamond detector window is negatively polarized to produce a basic layer on its surface by water decomposition. Actinides elements that are known to be very sensitive to hydrolysis are precipitated as solid hydroxides onto the entrance window of the sensor. Due to the absence of an air layer between the radioactive source and the detector, there is no need for vacuum during the alpha spectrometry measurement. After analysis, the detector can be easily cleaned by anodization in the aqueous medium to be reused at once. The minimum detectable activity concentration (MDA) of the system has been evaluated with (241)Am at 0.5 Bq/L for a 0.33 cm(2) area Si PIN diode.
