Self-aggregation Of Oligonucleotide-functionalized Gold Nanoparticles And Isothermal Exponential Amplification Reaction For Highly Sensitive Detection Of DNA And MicroRNA

A new self-aggregation phenomenon of single strand DNA-modified gold nanoparticles (ssDNA-GNPs) is demonstrated. The self-aggregation can be prevented by hybridization between the ssDNA on GNPs and the complementary DNA. Thus, the self-aggregation of ssDNA-GNPs can be conveniently applied to sensitive DNA detection by visualization of color changes. The self-aggregation-based method for DNA detection is ideally suited to couple with the isothermal exponential DNA amplification reaction (EXPAR) for highly sensitive detection of DNA. We have further demonstrated that microRNAs are well suited for triggering the EXPAR reaction. Combining the simple, visual self-aggregation-based detection with the rapid, isothermal EXPAR reaction, it can detect microRNA at fmol/L level.