Primer-Modified G-Quadruplex-Au Nanoparticles for Colorimetric Assay of Human Telomerase Activity and Initial Screening of Telomerase Inhibitors.

Abstract

G-quadruplexes formed by 3'-overhang of guanine-rich human telomeric DNA at the end of chromosome have important implication in inhibiting the telomerase activity. Telomerase catalyzes the elongation of telomeres by adding telomeric repeats sequence TTAGGG onto the end of the chromosome. Since telomerase is over-expressed in 80-90% of all known human tumors, the enzyme can be recognized as a biomarker for cancer diagnosis and a therapeutic target. Thus, the sensitive detection of telomerase activity is essential to cancer diagnosis and therapy, and screening of anticancer drugs. Gold nanoparticles (AuNPs) have been widely applied as a colorimetric probe for assay owing to their unique size- and distance-dependent optical properties. Human telomerase activity can be visualized by using primer-modified Au nanoparticles. The extremely high extinction coefficients of AuNPs offered high sensitivity. Here, we describe a protocol for the preparation of primer-modified Au nanoparticles for colorimetric assay of human telomerase activity and initial screening of telomerase inhibitors.