Signal Amplification and Application Methods Using Gold Nanoparticle-Conjugated Nucleic Acid Nanostructures

Point-of-Care Nucleic Acid Detection Kit Using Hybridization Chain Reaction and Gold Nanoparticle Color Change

This technology is a target nucleic acid detection kit consisting of two types of hairpin-structured oligomers with toehold sequences that bind to target nucleic acids, and 10–15 nm diameter gold nanoparticles attached to the end of one of them. Only in the presence of the target do the hairpins open to form nanostructures via hybridization chain reaction, causing the gold nanoparticles to aggregate and change the color of the solution.

Pathogenic microorganism detection has traditionally relied on post-culture observation, ELISA, PCR, or real-time PCR, all of which require specialized personnel, expensive equipment, and long processing times. Highly infectious diseases are difficult to diagnose on-site, necessitating travel to testing facilities, which increases the risk of infection spread.

This technology allows reactions to proceed at room temperature and enables non-experts to rapidly identify target DNA/RNA without equipment by observing the loss of red color visually or via absorbance. Since hairpin sequences can be designed for specific targets, it can be applied to point-of-care diagnostic kits and screening platforms for pathogenic viruses and bacteria, helping to curb the early spread of infectious diseases.

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Key Features:

• Oligomer A, which sequentially includes toehold sequence A, nucleic acid sequence A1, loop sequence A, and nucleic acid sequence A2, binds complementarily to the target nucleic acid and forms a 39–46 bp hairpin
• Hairpin-structured oligomer B, which sequentially includes nucleic acid sequence B1, loop sequence B, nucleic acid sequence B2, and toehold sequence B, and binds complementarily to the sequence of oligomer A
• Gold nanoparticles with a diameter of 10 to 15 nm attached to the end opposite the toehold sequence of hairpin-structured oligomer A or B
• A step of performing a hybridization chain reaction to determine the presence of target nucleic acids in a sample using the target nucleic acid detection kit

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This invention was developed with support from the Ministry of Science and ICT for the development of non-viral gene therapy nano-assembly skin delivery technology.

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