The Sensitization of Scintillation in Polymeric Composites Based on Fluorescent Nanocomplexes

The sensitization of scintillation was investigated in crosslinked polymeric composite materials loaded with luminescent gold clusters aggregates acting as sensitizers, and with organic dye rhodamine 6G as the emitting species. The evolution in time of the excited states population in the systems is described by a set of coupled rate equations, in which steady state solution allowed obtainment of an expression of the sensitization efficacy as a function of the characteristic parameters of the employed luminescent systems. The results obtained indicate that the realization of sensitizer/emitter scintillating complexes is the strategy that must be pursued to maximize the sensitization effect in composite materials.

Cyclic Peptide Modified Gold Clusters Induce Lung Tumor Cell Apoptosis via Generating Intracellular Oxidative Stress

Metastatic lung cancer is the leading cause of death for cancer patients. Although many chemical drugs were developed for cancer treatment, metastatic cancer mortality did not decrease significantly. In this article, we designed an Au clusters (AuCs) modified by cyclic RGD peptides which well target the integrin of human lung carcinoma cells (A549). The RGD-AuCs could well induce A549 cells apoptosis, but have no cytotoxicity on the human bronchial epithelial cells (16HBE), which are normal cells support respiratory system. The AuCs could be internalized and localized in the lysosomes of A549 tumor cells and further release into cytoplasma. We found the ROS level was increased by AuCs, and such high ROS level finally leads to depolarization of mitochondria. Eventually, the AuCs stimulating mitochondria related apoptosis pathway to induce A549 tumor cells apoptosis. We deduce the gold clusters would be an effective therapeutic candidate to against metastatic lung tumor in the future studies.

SPUTTERING OF GOLD AND COPPER SURFACES UNDER LOW ENERGY CESIUM IONS

To use gold and copper ions for ion implantation through 1-MV pelletron accelerator, gold and copper targets were bombarded with low energy cesium ions applying source of negative ions by cesium sputtering (SNICS). This work aims to investigate the cluster dynamics of these noble metals in a low energy range so that optimized data can be obtained for the use of these cluster ions in ion implantation. Negative ions including monomers and clusters of both metals were detected which were mass analyzed. Cu clusters up to Cu[Formula: see text] and gold clusters up to Au[Formula: see text] were emitted. The minimum energy of cesium ions to produce enough cluster ions so that they could be detected by a mass analyzer has been determined. The data was analyzed to measure sputtering yield, total sputtering yield and normalized number density of different sputtered species. In this energy range, the sputtering behaviors of Cu remain almost constant but in the case of Au there is a slight increase in cluster sputtering probability with an increase in incident ion energy. The sputtering yield of clusters decreases according to the power-law, i.e. [Formula: see text]. Power law exponent in the case of copper has an average value of [Formula: see text] whereas exponent in the case of gold clusters changes from 3.5 to 6.