Polymer nano-particles (PNPs) with a near-infrared (NIR) light absorption were prepared by the nano-emulsion method to develop contrast agents for photo-acoustic (PA) imaging. The PNP containing silicon naphthalocyanine showed a high absorption coefficient up to 10(10) M(-1) cm(-1). This is comparable to plasmonic gold nano-particles, which have been studied as PA contrast agents. For the PNP larger than 100 nm, the enhancement of the PA signal was observed compared to the gold nano-particle with a similar absorption coefficient and size. In the case of the PNP, the heat by the light absorption is confined in the particle due to the low thermal diffusivity of polymer materials. We showed that the strong thermal confinement effect of PNP results in the enhancement of the efficiency of the PA signal generation and that the PA intensity can be enhanced by the increase of the Grüneisen parameter of the matrix polymer of PNP. The PA signal from the PNP of poly(methyl methacrylate) was 9-fold larger than that of gold nano-particles with the same absorption coefficient. We demonstrated that in the in vivo PA imaging the detection limit of PNP was of the order of 10(-13) M. The NIR absorbing PNP will be a promising candidate of a sensitive contrast agent for PA imaging.

This paper reports an improvement of the detectability in the capillary electrophoretic analysis of glycoproteins by using a sweeping technique based on the complexation between glycoproteins and borate ions: sweeping via borate complexation. In this technique, an anionic glycoprotein solution containing no borate ions is injected as a long plug into a capillary filled with a borate buffer. Due to the complexation between glycoproteins and borate ions, the analytes in a long sample zone are swept by borate ions to a narrow zone. When 1-acid glycoprotein dissolved in a phosphate buffer was injected into poly(vinylpyrrolidone) coated capillary filled with 50 mM borate buffer (pH 10.0) for 120 s, the 30-40 fold increase in the sensitivity was achieved relative to conventional zone electrophoretic analysis. Furthermore, three glycoproteins could be separated with enhanced sensitivities under the sweeping via borate complexation condition. The enrichment efficiency was dependent on the sugar chain content of the glycoproteins. This indicated that the complexation of glycoproteins with borate ions played a crucial role in the sweeping via borate complexation technique.

We have successfully developed a novel near‐infrared (NIR) polarizer fabricated from dichroic dyes. Unlike conventional wire‐grid polarizers, it exhibits transparency in the visible region and polarization wavelength tunability. Improvement of iris pattern recognition by eliminating the reflected light from the cornea surface has been demonstrated.