Realizing photolithography on three-dimensional structures is useful for micromachining; however, a thin and uniform resist film is difficult to prepare on a non-planar sample. A spray coating technique has the potential to deposit a uniform and defect-free resist film on a three-dimensional structure. In this study, the characteristics of spray coating are examined focusing on spray flow speed. Faster spray flow is found to remove the pinhole defects even at the bottom of a deep cavity with a high aspect ratio. The results of patterning performance on a deep three-dimensional structure are also shown. A line-and-space pattern on a 200 µm deep groove is demonstrated to have thick and thin resist coverage at the convex and concave corners, respectively with no pinhole defects. The obtained results of the spray coated resist film are discussed based on the fluid dynamics.

No abstract

Pandemic influenza, triggered by the mutation of a highly pathogenic avian influenza virus (IFV), has caused considerable damage to public health. In order to identify such pandemic IFVs, antibodies that specifically recognize viral surface proteins have been widely used. However, since the analysis of a newly discovered virus is time consuming, this delays the availability of suitable detection antibodies, making this approach unsuitable for the early identification of pandemic IFVs. Here we propose a label-free semiconductor-based biosensor functionalized with sialic-acid-containing glycans for the rapid identification of the pandemic IFVs present in biological fluids. Specific glycans are able to recognize wild-type human and avian IFVs, suggesting that they are useful in discovering pandemic IFVs at the early stages of an outbreak. We successfully demonstrated that a dual-channel integrated FET biosensing system, which were modified with 6′-sialyllactose and 3′-sialyllactose for each gate area, can directly and specifically detect human H1N1 and avian H5N1 IFV particles, respectively, present in nasal mucus. Furthermore, to examine the possibility of identifying pandemic IFVs, the signal attributed to the detection of Newcastle disease virus (NDV) particles, which was selected as a prime model of a pandemic IFV, was clearly observed from both sensing gates. Our findings suggest that the proposed glycan-immobilized sensing system could be useful in identifying new pandemic IFVs at the source of an outbreak.

No abstract

In the present study, we successfully obtained nonstaining blood flow images of a developing fish egg embryo using optical interference caused by the Doppler shift. The spectral distribution of light reflected by moving objects such as the heart and red cells was found to be different from that of the incident light because of the Doppler effect. Interference between different frequency components was observed in an interferogram through heterodyne interaction using an imaging-type two-dimensional Fourier spectroscopic system, and information on the intensities of the spectral components was obtained by Fourier transformation. Beat signals with specific frequencies due to the heart beating and blood flow of the fish egg embryo were detected. When the signals were plotted in two dimensions, the heart part and vessel flows were clearly visualized without staining. In addition, near-infrared (NIR) images were produced using absorbance spectra of the molecular vibrations of O-H and C-H groups included in water, hydrocarbons, and aliphatic compounds. Obtaining nonstaining blood flow images using heterodyne optical interference and images of molecular distribution using molecular vibrational information simultaneously manifests an exciting advance in NIR imaging.