In this paper, a new interactive algorithm for image segmentation is proposed. First, threshold segmentation is applied to the original image, and the corresponding foreground image and background image are obtained. In the foreground image, some manually selected contour pixel points of the pattern to be segmented will become the initial seed points. The set composed of seed points is defined as set E. Then, the distances between each pixel point in foreground image and each seed point in set E are computed. If the minimum distance is less than the threshold, the pixel point with minimum distance is labeled as seed point, and added to the set E. Until all the pixel points in the foreground image have been labeled, the seed points in the final set E compose the segmentation image. At last, the effectiveness of the proposed algorithm is proved by a simulation.
This paper reports the near-infrared (NIR) SERS detection of immune reaction on gold colloid particles without bound/Free (B/F) antigen separation. Antibodies or the immune complex are adsorbed on gold colloid particles. Free antigen cannot be adsorbed on the gold colloid particles due to the surface of the gold colloid particles is blocked by bovine serum albumin. Because of the electromagnetic field generated by surface plasmon polariton enhancement, the antibody at 10<sup>-8</sup> M on the gold colloid particles shows intense SERS signals. The same system at 10<sup>-10</sup> M does not give any SERS signal, but Raman bands of antibody again appear upon the formation of immunoglobulin (IgG)-anti-IgG complexes on the gold colloid particles. Free and bound antigen molecules do not yield significant SERS signals since they cannot be adsorbed directly on the gold surface. In this way, one could detect the immune complex on the gold colloid particles by NIR SERS spectroscopy without any B/F antigen separation.
This paper reports effects of electrostatic interaction between amino acid and gold colloid on the intensity of surface-enhanced raman scattering (SERS). Near-infrared (NIR) excited SERS has been measured for lysine (Lys) on gold colloid at pH 10.8 and 12.0 where its ε-amino group is ionized and both the α- and ε-amino groups are neutralized, respectively. Note that the SERS intensity changes dramatically with pH. This result suggests that the electrostatic interaction between the positive charge of the ε-NH<sub>3</sub><sup>+</sup> group and the negative charge of the gold surface is one of the most important factors that determine the intensities of the SERS signals.
This paper reports a kind of application of surface-enhanced Raman scattering (SERS) to immunology. In the proposed system, antibody immobilized on a solid substrate reacts with antigen, which binds with another antibody labeled with peroxidase. If this immunocomplex is subjected to reaction with o-phenylenediamine and hydrogenperoxide at 37°C, azoaniline is generated. This azo compound is adsorbed on a silver colloid and only the azo compound gives a strong surface-enhanced resonance Raman (SERRS) spectrum. A linear relationship was observed between the peak intensity of the N=N stretching band and the concentration of antigen, revealing that one can determine the concentration of antigen by the SERRS measurement of the reaction product.