Labelled Silica Nanoparticles for Immunochromatographic Reagent, Immunochromatographic Test Strip Using the Same, and Immunochromomatographic Fluorescence-Detecting System or Radiation-Detecting System

An immunochromatographic fluorescence-detecting system, comprising:

• an immunochromatographic test strip, comprising
• 1) a sample application member,
• 2) a member impregnated with an immunochromatographic reagent comprising labeled silica nanoparticles, wherein said labeled silica nanoparticles are both surface-modified with an analyte-recognizing substance and bonded with polyethylene glycol,
• 3) a membrane having an antibody-immobilized region, and
• 4) an absorption pad,
• wherein 1)-4) are connected in series, and
• wherein the immunochromatographic reagent allows high-sensitivity detection by detection of fluorescence emitted from the silica nanoparticles containing the fluorescent substance, and wherein the wavelength of an excitation light source used for detection of the fluorescence emitted from the silica nanoparticles is 200 nm to 600 nm.

An immunochromatographic radiation-detecting system, comprising:

• an immunochromatographic test strip, comprising
• 1) a sample application member,
• 2) a member impregnated with an immunochromatographic reagent comprising labelled silica nanoparticles, wherein said labelled silica nanoparticles are both surface-modified with an analyte-recognizing substance and bonded with polyethylene glycol,
• 3) a membrane having an antibody-immobilized region, and
• 4) an absorption pad,
• wherein 1)-4) are connected in series, and
• wherein radiation emitted from the silica nanoparticles is measured with a Geiger counter or by photosensitizing an X-ray film.