A visualized automatic particle counting strategy for single‐cell level telomerase activity quantification

The accurate evaluation of telomerase activity, a typical cancer biomarker, is vital for early screening. In this study, we developed dark-field microscopy (DFM) visual single-particle detection scheme to detect activity based on automatic counting gold nanoparticles (AuNPs). This method started with attaching the substrate (TS) primer magnetic beads (MBs) through streptavidin-biotin interaction. presence and dNTPs, TS was expanded (TTAGGG)n repeat units form extension product (MBs-telomerase product), which could be hybridized complementary DNA (cDNA) modified AuNPs Au-S bonds (AuNPs-SH-cDNA). After separation double-strand unwinding, were collected from supernatant, quantitatively measured by visually bright spots DFM. strategy achieved limit as low 1 HeLa cell distinguished among different lines, thus verifying its excellent sensitivity specificity. Further, two common inhibitors (BIBR1532 curcumin) screened consistent IC50 values other methods, respectively. It worth mentioning that can clearly identify bladder various urinary diseases. Consequently, visualized particle potential powerful tool in noninvasive diagnosis cancer.