A numerical analysis of a shear horizontal surface acoustic wave (SH-SAW) immunoassay biosensor has been investigated. A numerical calculation method proposed by Campbell and Jones has been generally used to calculate SAW propagation characteristics. In this paper, a numerical calculation method for SH-SAW propagation characteristics, which is a modified method of Campbell and Jones involving the effect of liquid viscosity is applied to quartz. In order to confirm the numerical analysis, 250 MHz SH-SAW delay-lines on quartz substrates are tested using glycerol mixtures of different concentrations of 0, 10, 20 and 30 wt%. In the experiments, the velocity and attenuation changes of the SH-SAWs are seen to increase as glycerol mixture concentrations are incrementally increased, as theoretically expected. Very good agreements between theoretical and experimental results are obtained.

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We try to develop the sterilization process for medical instruments using atmospheric pressure plasma. The reactor chamber is remotely located from the plasma and a metal mesh for eliminating charged particles is installed between them. Only reactive neutral species such as plasma-excited gas molecules and radicals were separated from the plasma and sent to the reactor chamber for sterilization. Deterioration of materials by heat, UV irradiation, electrical fields, and charged particles generated from plasma is avoided in the sterilization process. As a result, using a humidified mixture of 0.1 to 20% oxygen addition to nitrogen as the plasma source gas shows more than 6-log reduction of Geobacillus stearothermophilus spores. The mixture gas of 0.1% oxygen addition to nitrogen shows the large sterilization effect without ozone generation. Under this condition, the surface of titanium, silicon rubber, PET, and nylon-6 are not affected by the sterilization.

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We report a lensless complementary metal-oxide-semiconductor (CMOS) imaging device that can obtain fluorescence and non-fluorescence images for digital enzyme linked immunosorbent assay (ELISA). In lensless imaging, it is important to manage the degradation of the spatial resolution with beam propagation. For fluorescence imaging, we applied an image processing technique based on deconvolution method to recover the spatial resolution. For non-fluorescence imaging, a collimated illumination is used and the detection error is reduced by using an angle scanning technique.

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Stretchable dry electrodes for measuring biological signals were prepared on a stretchable textile substrate by printing an elastomer-based electrically-conductive paste with Ag fillers loading. Interfacial impedance between electrode and skin was suggested to vary depending on contact pressure of electrodes and water content of stratum corneum. When water content of stratum corneum was >30%, electrocardiograms (ECG) could be measured using the stretchable electrodes printed on a compression shirt. By contrast, significant noise prevented to detect ECG signals when water content of stratum corneum was <30%. To resolve this problem, supporting electrodes consisting of an electrically-conductive polyurethane form were prepared using a sonoprocess. Because the supporting electrodes are effective to increase contact pressure of electrodes, ECG could be measured even at the low water contents of stratum corneum by using the supporting electrodes. In addition, ECG signals were successfully monitored during walking by achieving sufficient contact between electrodes and skin.

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