Although conventional computer technology made a huge leap forward in the past decade, a vast number of computational problems remain inaccessible due to their inherently complex nature. One solution to deal with this computational complexity is to highly parallelize computations and to explore new technologies beyond semiconductor computers. Here, we report on initial results leading to a device employing a biological computation approach called network-based biocomputation (NBC). So far, the manufacturing process relies on conventional Electron Beam Lithography (EBL). However we show first promising results expanding EBL patterning to the third dimension by employing Two-Photon Polymerization (2PP). The nanofabricated structures rely on a combination of physical and chemical guiding of the microtubules through channels. Microtubules travelling through the network make their way through a number of different junctions. Here it is imperative that they do not take wrong turns. In order to decrease the usage of erroneous paths in the network a transition from planar 2-dimensional (mesh structure) networks to a design in which the crossing points of the mesh extend into the 3rd dimension is made. EBL is used to fabricate the 2D network structure whereas for the 3D-junctions 2PP is used. The good adaptation of the individual technologies allows for the possibility of a future combination of the two complementary approaches.
Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trapped in air using a 1064 nm laser. The positions visited by the trapped gold nano-particle were quantified using a quadrant photo diode placed in the back focal plane. The time traces were analyzed and the trapping stiffness characterizing gold aerosol trapping determined and compared to aerosol trapping of nanometer sized silica and polystyrene particles. Based on our analysis, we concluded that gold nano-particles trap more strongly in air than similarly sized polystyrene and silica particles. We found that, in a certain power range, the trapping strength of polystyrene particles is linearly decreasing with increasing laser power.
Brownian motors combine asymmetry (such as a “ratchet” potential) and stochastic (thermal) motion with non-equilibrium processes to generate directed particle flow. A brief general introduction to Brownian motors is given, and the relevance of the ratchet model for biological motor proteins is highlighted. However, the impact of research on Brownian motors goes far beyond biophysics. A wealth of novel phenomena has been predicted, and some of these phenomena have been observed in areas as diverse as synthetic chemistry, bio-molecular colloids, self-organizing systems, quantum electronics, micro-fluidics, and materials science. Applications, such as novel actuators and molecular separation techniques, are evolving quickly. In the oral presentation, I will attempt to give an overview on applications of ratchets and Brownian motors. In the present paper, I give a short overview and review then a recent experimental realization of a tunneling ratchet for electrons. Such electron tunnelling ratchets can not only be used to generate particle currents, but also to pump heat. Using a realistic model, the heat pumping properties of the experimental electron ratchet are analysed.
Ratchets are systems that combine asymmetry with non-equilibrium processes to generate directed particle flow. A brief general introduction to ratchets is given, and the relevance of the ratchet model for biological motor proteins is highlighted. While biological motor proteins operate classically, ratchet systems that employ quantum effects are of interest from a fundamental point of view. A recent experimental realization of a tunnelling ratchet for electrons is reviewed. Such electron tunnelling ratchets can not only be used to generate particle currents, but also to pump heat. Using a realistic model, the heat pumping properties of the experimental electron ratchet are analysed.
Conference Committee Involvement (1)
Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIII
16 February 2016 | San Francisco, California, United States
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