We report a way of fabricating high-quality void-free high-aspect-ratio metallic stamps of 100nm width and 2μm depth, using the technique of proton beam writing coupled with electroplating using a nickel sulfamate solution. Proton beam writing is a one-step direct-write process with the ability to fabricate nanostructures with high-aspect-ratio vertical walls and smooth sides, and as such has ideal characteristics for three-dimensional (3D) stamp fabrication. Nanoindentation and atomic force microscopy measurements of the nickel surfaces of the fabricated stamp show a hardness and side-wall roughness of 5GPa and 7nm, respectively. The fabricated 100nm 3D stamps have been used to transfer test patterns into poly(methylmethacrylate) films, spin coated onto a silicon substrate. Proton beam writing coupled with electroplating offers a process of high potential for the fabrication of high quality metallic 3D nanostamps.

In the emerging fields of nanoscience and nanotechnology, the demands for low-cost and high-throughput nanolithographic techniques have increased. Nanoimprint lithography is considered as one of the candidates showing high potential for nanofabrication, and here we report a fabrication process that utilizes high-quality nickel stamps with micron features down to sub-100 nm, made using proton beam writing coupled with nickel sulfamate electroplating. The fabricated stamps have a high aspect ratio, with smooth and vertical sidewalls. Nanoindentation and atomic force microscopy (AFM) measurements of the features on the surface of the stamps indicate a hardness of 5 GPa and a sidewall roughness of 7 nm. The stamps have been used for nanoimprint lithography on polymethylmethacrylate (PMMA) substrates and the imprinted patterns show a high degree of reproducibility.

We report a technique for fabricating enclosed nanochannels in poly(methylmethacrylate) (PMMA) using proton beam writing coupled with thermal bonding. Using proton beam writing, straight-walled high-aspect-ratio channels can be directly fabricated through a relatively thick PMMA resist layer spin coated on a Kapton film. By thermally bonding the fabricated structures onto bulk PMMA, peeling off the Kapton substrate, and bonding the remaining exposed side to PMMA, enclosed high-aspect-ratio nano/microchannels can be fabricated. Such enclosed channels can be incorporated into fluidic polymeric devices, and the process is compatible with the fabrication of multilevel three-dimensional fluidic chips with vertical interconnects.

A new design for a compact portable lab-on-a-chip instrument based on MCE and dual capacitively coupled contactless conductivity detection (dC(4) D) is described. The instrument is battery powered with total dimension of 14 × 25 × 8 cm(3) (w × l × h), and weighs 1.2 kg. The device consists of a front electrophoresis compartment which has the chip holder and the chip, the associated high-voltage electrodes for electrophoresis injection and separation and the detector. The detection cell is integrated into the device housing with an exchangeable plug-and-play cartridge format. The design of the dC(4) D cell has been optimized for maximum performance. The cartridge includes the top-bottom excitation and pick up electrodes incorporated into the cell and connected to push-pull self-latching pins that are insulated with plastic. The metal frame of the cartridge is grounded completely to eliminate electronic interferences. The cartridge is designed to clamp a thin fluidic chip at the detection point. The cartridges are replaceable whereby different cartridges have different detection electrode configurations to employ according to the sensitivity or resolution needed in the specific analytical application. The second compartment consists of all the electronics, data acquisition card, high-voltage modules of up to ±5 kV both polarity, and batteries for 10 h of operation. The improved detector performance is illustrated by the electrophoresis analysis of six cations (NH4 (+) , K(+) , Ca(2+) , Na(+) , Mg(2+) , Li(+) ) with a detection limit of approximately 5 μM and the analysis of the anions (Br(-) , Cl(-) , NO2 (-) , NO3 (-) , SO4 (2-) , F(-) ) with a detection limit of about 3 μM. Analytical capabilities of the instrument for food and medical applications were evaluated by simultaneous detection of organic and inorganic acids in fruit juice and inorganic cations and anions in rabbit blood samples and human urine samples are also demonstrated.

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