[en] The design and fabrication of an ordered nanoporous silicon membrane and integrated heater and temperature sensor is described. The methodology for fabrication of the nanoporous structure has been developed for integration within microelectromechanical systems. The structure is fabricated from a 500 µm thick silicon 〈1 0 0〉 wafer, which has been etched to provide 4 × 4 mm"2 membranes of 50 µm thick. Quasi-ordered nanoporous silicon is created within the membrane, the nanopores are of uniform diameter (typical structures of the order of 105 + 5 nm) and smooth sidewalls to a depth of ∼300 nm, in a hexagonal close-packed pattern of 200 nm nearest neighbour. The porosity of typical fabricated samples is 31.5%. On the back side of the membrane, a heater and a temperature sensor are incorporated. Three different heater/temperature sensor designs were considered theoretically and the best design was then fabricated and studied experimentally. The results obtained provide both highly ordered nanoporous silicon fabrication methodology as well as evidence that the porous membrane can be heated without deleterious effect. (paper)

[en] The fabrication of ordered macroporous silicon is obtained by exploiting the self-assembly properties of polymer nanospheres. Here, we demonstrate the method by using nanospheres of 200 nm and 500 nm. These self-assemble in monolayers of ordered hexagonal close-packed nanospheres. A controlled reactive ion etch of the assembled nanospheres, subsequent evaporation of metal, followed by 'lift-off' of the polymer nanospheres, provides a mask suitable for a further reactive ion etch step to provide macroporous polysilicon. This methodology provides a novel approach for the fabrication of highly ordered macroporous polysilicon; porous silicon substrates with pores of this size (50–500 nm) were previously only fabricated using rather difficult processing methods. The method reported here is straightforward and achieved using fabrication methods that are compatible with those currently used for microelectromechanical systems (MEMS), photonic devices and nanostructured surfaces

[en] A novel sloped interconnect for the efficient delivery of long genomic DNA fragments into a microfluidic channel is designed, fabricated and tested. Out-of-plane slopes are fabricated in silicon wafers using the deep reactive-ion etch lag phenomenon and a combination of anisotropic and isotropic etching. The final structure is capped with anodically bonded glass. Based upon a series of etch-lag calibration studies, the interconnect was designed using finite element analysis to provide a channel with flow acceleration properties appropriate to straighten DNA molecules. The efficiency of transit of the 48.5 kb DNA fragments (∼16.5 µm long when fully extended) through the microfluidic device, established using quantitative real-time polymerase chain reaction, is 95 ± 7.3%

[en] Here we present the first evidence showing that eukaryotic cells can be stably trapped in a single focused Gaussian beam with an orientation that is defined by the nucleus. A mammalian eukaryotic cell (in suspension) is trapped and is re-oriented in the focus of a linearly polarized Gaussian beam with a waist of dimension smaller than the radius of the nucleus. The cell reaches a position relative to the focus that is dictated by the nucleus and nuclear components. Our studies illustrate that the force exerted by the optical tweezers at locations within the cell can be predicted theoretically; the data obtained in this way is consistent with the experimental observations. (communication)

[en] Three-dimensionally structured gold membrane films with nanopores of defined, periodic geometries are designed and fabricated to provide the spatially localised enhancement of electric fields by manipulation of the plasmons inside nanopores. Square nanopores of different size and orientation relative to the pyramid are considered for films in aqueous and air environments, which allow for control of the position of electric fields within the structure. Designs suitable for use with 780 nm light were created. Here, periodic pyramidal cavities produced by potassium hydroxide etching to the {111} planes of (100) silicon substrates are used as templates for creating a periodic, pyramidal structured, free-standing thin gold film. Consistent with the findings from the theoretical studies, a nano-sized hole of 50 nm square was milled through the gold film at a specific location in the cavity to provide electric field control which can subsequently used for enhancement of fluorescence or Raman scattering of molecules in the nanopore. (paper)