Paper-based, nucleic acid-detecting kit and method for analysis of PCR amplicon

A paper-based, nucleic acid-detecting sensor consisting of:

• a negatively-charged porous first paper substrate;
• a separation layer stacked on one surface of the first paper substrate and comprising Sepharose beads and glass beads;
• and
• a negatively-charged porous second paper substrate stacked on one surface of the separation layer;
• wherein, when a labeled PCR amplicon and a capture nanoparticle are added onto the second paper substrate, the labeled PCR amplicon and the captured nanoparticle move through the second paper substrate and pass to the separation layer in this order;
• wherein the labeled PCR amplicon comprises a label selected from the group consisting of avidin, biotin, avidin-biotin, an antigen, a target molecule, and an oligonucleotide;
• wherein the capture nanoparticle is coated with a capture molecule capable of binding the label of the PCR amplicon, and wherein the capture molecule is selected from the group consisting of avidin, streptavidin, an antibody, an aptamer, and an oligonucleotide;
• wherein the first paper substrate is for visualizing, with the naked eye, a complex formed between a labeled target nucleic acid in the PCR amplicon and the coated capture nanoparticle that spreads on the first paper substrate after passing through the separation layer without staying in the separation layer;
• and
• wherein a total area of the second paper substrate is 2 to 10 times smaller than a total area of the first paper substrate.