Photochemical internalization in bladder cancer - development of an orthotopic in vivo model

The possibility of using photochemical internalization (PCI) to enhance the effects of the cytotoxic drug bleomycin is investigated, together with photophysical determination and outlines of a possible treatment for intravesical therapy of bladder cancer. In vitro experiments indicated that the employment of PCI technology using the novel photosensitizer TPCS_2a® can enhance the cytotoxic effect of bleomycin in bladder cancer cells. Furthermore, experiments in an orthotopic in vivo bladder cancer model show an effective reduction in both the necrotic area and the bladder weight after TPCS_2a based photodynamic therapy (PDT). The tumor selectivity and PDT effects may be sufficient to destroy tumors without damaging the detrusor muscle layer. Our results present a possible new treatment strategy for non-muscle invasive bladder cancer, with the intravesical instillation of the photosensitizer and bleomycin followed by illumination through an optic fiber by using a catheter.

Effects of substrate annealing on the gold-catalyzed growth of ZnO nanostructures

The effects of thermal substrate pretreatment on the growth of Au-catalyzed ZnO nanostructures by pulsed laser deposition are investigated. C-plane sapphire substrates are annealed prior to deposition of a thin Au layer. Subsequent ZnO growths on substrates annealed above 1,200°C resulted in a high density of nanosheets and nanowires, whereas lower temperatures led to low nanostructure densities. Separate Au film annealing experiments at 700°C showed little variation in the size and density of the Au catalyst droplets with substrate annealing temperature. The observed variation in the density of nanostructures is attributed to the number of surface nucleation sites on the substrate, leading to a competition between nucleation promoted by the Au catalyst and surface nucleation sites on the rougher surfaces annealed below 1,200°C.