RESUMO
Here we describe the production, using lithography and micro-engineering technologies, of patterned arrays of nanofabricated gold dots on a thin Si3N4 electron transparent layer, supported by silicon. We illustrate that the support with a patterned structure of nanosized gold can be exploited for (cryo) electron tomography application as a specimen support with predefined alignment markers. This nanogold patterned support has several advantages. The Si3N4 window provides a 50 nm thin, strong and flat support with a ~0.7 mm(2) large electron-beam transparent window. The nanogold pattern has a user-defined size and density, is highly regular and stable. This facilitates accurate tracking during tilt series acquisition, provides sufficient contrast for accurate alignment during the image reconstruction step and avoids an uneven lateral distribution and movement of individual fiducials. We showed that the support is suitable for electron tomography on plastic sections.
RESUMO
In this paper, we present the analysis of electroosmotic flow in a branched -turn nanofluidic device, which we developed for detection and sorting of single molecules. The device, where the channel depth is only 150 nm, is designed to optically detect fluorescence from a volume as small as 270 attolitres (al) with a common wide-field fluorescent setup. We use distilled water as the liquid, in which we dilute 110 nm fluorescent beads employed as tracer-particles. Quantitative imaging is used to characterize the pathlines and velocity distribution of the electroosmotic flow in the device. Due to the device's complex geometry, the electroosmotic flow cannot be solved analytically. Therefore we use numerical flow simulation to model our device. Our results show that the deviation between measured and simulated data can be explained by the measured Brownian motion of the tracer-particles, which was not incorporated in the simulation.
