In this paper the characterization of different masking materials for the fabrication of flow channels or thin diaphragms in aluminosilicate glass substrates (Corning 1737) is presented. Materials such as photoresist, polysilicon and gold were investigated with concentrated hydrofluoric acid, HF 48% used as an isotropic etchant. The use of single material masks restricts the useable etch depth to less than 250 µm. Surface and material imperfections result in weaknesses in the masking layer and subsequent penetration by the etchant. An etch depth of greater than 300 µm was achieved using a combination of thick SU-8 photoresist and polished polycrystalline silicon as the masking material. The two materials act as double protection to the glass substrate and the etch depth obtained is approximately three to six times larger than those published for standard photoresist or SU-8 etch mask.

The development of new point of care coagulation assay devices is necessary due to the increasing number of patients requiring long-term anticoagulation in addition to the desire for appropriate, targeted anticoagulant therapy and a more rapid response to optimization of treatment. The majority of point of care devices currently available for hemostasis testing rely on clot-based endpoints which are variable, unreliable and limited to measuring only certain portions of the coagulation pathway. Here we present a novel fluorescence-based anti-Factor Xa (FXa) microfluidic assay device for monitoring the effect of anticoagulant therapy at the point of care. The device is a disposable, laminated polymer microfluidic strip fabricated from a combination of hydrophobic and hydrophilic cyclic polyolefins to allow reagent deposition in addition to effective capillary fill. Zeonor was the polymer of choice resulting in low background fluorescence (208.5 AU), suitable contact angles (17.5 AE 0.9 ) and capillary fill times (20.3 AE 2.1 s). The device was capable of measuring unfractionated heparin and tinzaparin from 0-0.8 U ml À1 and enoxaparin from 0-0.6 U ml À1 with average CVs < 10%. A linear correlation was observed between the device and the fluorescent assay in the plate for plasma samples spiked with UFH, with an R 2 value of 0.99, while correlations with tinzaparin and enoxaparin resulted in sigmoidal responses (R 2 ¼ 0.99). Plasma samples containing UFH resulted in a linear correlation between the device and a standard chromogenic assay with an R 2 value of 0.98, with both LMWHs resulting in sigmoidal relationships (R 2 ¼ 0.99).

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The results on structural damage in germanium wafers caused by hydrogen and helium implants of typical doses used in Smart Cut™ Technology (1–6 × 1016 atoms/cm2) are investigated using Raman mapping and spreading resistance profiling techniques. Raman line‐mapping measurements were performed up to the depth of ~400 nm into a Ge substrate (well beyond the limit of visible light penetration depth) using a bevelling technique. From analysis of the Ge–Ge Raman peak it was found that implantation of H and He introduced a different type of stress, tensile and compressive, respectively and significant structural damage with maximum at the projected range. The obtained data shows that hydrogen incorporation in Ge can act as an acceptor. This is undesirable when the hydrogen ion‐cut technology is applied to high resistivity Ge. The crystalline structure after implantation is completely recovered when annealed at 600 °C for both types of implants. Spreading resistance profiling results reveal that 4−8x1015 acceptors/cm3 remain after 600 °C, and these are thought to be because of vacancy related defect clusters. Copyright © 2011 John Wiley & Sons, Ltd.