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 labelled silica nanoparticles are both surface-modified with at least one analyte-recognizing substance and bonded with polyethylene glycol and bovine serum albumin (BSA), wherein the labelled silica nanoparticles have an active group that forms a covalent bond to a silane-coupling agent, wherein the active group is selected from the group consisting of a N-hydroxysuccinimide (NHS) ester group, a maleimide group, an isocyanate group, an isothiocyanate group, an aldehyde group, a para-nitrophenyl group, a diethoxymethyl group, an epoxy group, or a cyano group, and
• wherein the silane-coupling agent comprises 3-[2-(2-aminoethylamino)ethylamino]propyltriethoxysilane,
• 3) a membrane having an antibody-immobilized region in which the labelled silica nanoparticles are captured by a sandwiched immunocomplex-forming reaction to form immobilized antibody-analyte-labelled silica nanoparticles, 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 a 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 containing a radioactive substance, wherein said labelled silica nanoparticles containing a radioactive substance are both surface-modified with at least one analyte-recognizing substance and bonded with polyethylene glycol and bovine serum albumin (BSA), wherein the labelled silica nanoparticles have an active group that forms a covalent bond to a silane-coupling agent, wherein the active group is selected from the group consisting of a N-hydroxysuccinimide (NHS) ester group, a maleimide group, an isocyanate group, an isothiocyanate group, an aldehyde group, a para-nitrophenyl group, a diethoxymethyl group, an epoxy group, or a cyano group, and
• wherein the silane-coupling agent comprises 3-[2-(2-aminoethylamino)ethylamino]propyltriethoxysilane,
• 3) a membrane having an antibody-immobilized region in which the labelled silica nanoparticles containing a radioactive substance are captured by a sandwichedimmunocomplex-forming reaction to form immobilized antibody-analyte-labelled silica nanoparticles containing a radioactive substance, and
• 4) an absorption pad,
• wherein 1)-4) are connected in series, and
• wherein radiation emitted from the labelled silica nanoparticles containing a radioactive substance is measured with a Geiger counter or by photosensitizing an X-ray film.