Yoshitsugu Akiyama
Tokyo University of Science, Japan
Title: Colorimetric screening of DNA-functionalized gold nanoparticles with drugnucleic acid interactions
Biography
Biography: Yoshitsugu Akiyama
Abstract
Gold nanoparticles modified with high surface-density of DNA (DNA–AuNPs) have been widely used in highly sensitive bioassays. Until now, we developed a colorimetric single-nucleotide polymorphism (SNP) genotyping method and detected dynamic structural changes in DNA-AuNP assemblies with beads on string-like structure based on a unique phenomenon of non-crosslinking aggregation of double-stranded DNA-functionalized AuNPs (dsDNA–AuNPs). For example, dsDNA–AuNP having a full-match sequence can undergo aggregation in highly ionic aqueous solutions, showing a drastic color change owing to a band shift of the surface plasmon resonance. On the contrary, dsDNA–AuNP having a mismatch sequence can remain dispersed under the same conditions. Recently, we have also demonstrated the extremely higher colloidal stability of dsDNA–AuNP having a single-base protrusion as compared with that of dsDNA–AuNP having a mismatch sequence. This behavior allowed us to perform more reliable SNP genotyping of the human related-cytochrome P450 2C19 gene that plays a role in the metabolism of pharmaceutical agents. Notably, drastic color change can be induced by single-base differences in the dsDNA located on outermost surfaces of AuNP in highly ionic aqueous solutions.
In this study, we attempted to assess colorimetric drug efficacy of small molecules to facilitate selection of DNA-associated drugs that have a mechanism related to an antitumor activity. The rapid color difference derived from high colloidal stability can allow visual screening of potent antitumor agents.