No abstract

A polymer microchip with an open tip for electrospray mass spectrometry is presented. The tip consists of a groove with parallel walls where a droplet can form at the end surface. A lid covers the whole chip except at the microchannel tip, which is left open. Poly(dimethylsiloxane) (PDMS) microchips were cast using a nickel mould which in turn was replicated from a dry etched silicon wafer. Tips with microchannel widths of around 50 microm could easily be replicated. Since the tip had no cover, the assembly of microchip and cover was simplified. A total ion current variation of 5% during 300 s was achieved for a 1 microM myoglobin solution. The non-complex design of the cover makes it suitable for versatile tests of chip prototypes. The nickel mould was found to be useful for PDMS microstructure fabrication. Also, such a robust mould allows casting electrospray tips in more rigid thermoset materials.

We have micromachined a lateral symmetrically bistable buckled beam for snap-in holding structures by oxidizing released beams micromachined on thick silicon-on-insulator wafers. The wafers were prepared by bonding and chemical mechanical polishing, and the structures were fabricated by deep silicon reactive ion etching using the black silicon method, subsequently released and thermally oxidized. The bistability was monitored in situ in a scanning electron microscope using a micromanipulator. Guidelines for designing beams of an expected performance are given and arguments for considering beams that are not `fairly slender' have been found.

A design tool for fast and precise determination of the crystallographic orientation in (001) and (011) silicon wafers using anisotropic wet etching is introduced. The design takes advantage of the symmetric under-etching behaviour around, but not at (!), the -directions. The pattern needs to be etched only for a short time, and after a very quick optical inspection it can be used for aligning subsequent masks, using the same masking layer, more or less automatically. Two effects were investigated in a number of common anisotropic etchants: KOH, KOH with isopropyl alcohol (KOH/IPA), ethylenediamine based solutions (EDP), and tetramethyl ammonium hydroxide (TMAH). The precision of the method was found in most cases to be better than .

The RapidHIT ID is a fully automated sample-to-answer system for short tandem repeat (STR)-based human identification. The RapidHIT ID has been optimized for use in decentralized environments and processes presumed single source DNA samples, generating Combined DNA Index System (CODIS)-compatible DNA profiles in less than 90min. The system is easy to use, requiring less than one minute of hands-on time. Profiles are reviewed using centralized linking software, RapidLINK™ (IntegenX, Pleasanton, CA), a software tool designed to collate DNA profiles from single or multiple RapidHIT ID systems at different geographic locations. The RapidHIT ID has been designed to employ GlobalFiler Express and AmpFLSTR NGMSElect™, Thermo Fisher Scientific (Waltham, MA) STR chemistries. The Developmental Validation studies were performed using GlobalFiler Express with single source reference samples according to Scientific Working Group for DNA Analysis Methods guidelines. These results show that multiple RapidHIT ID systems networked with RapidLINK software form a highly reliable system for wide-scale deployment in locations such as police booking stations and border crossings enabling real-time testing of arrestees, potential human trafficking victims, and other instances where rapid turnaround is essential.