Convertible DNA ends-based silver nanoprobes for colorimetric detection human telomerase activity

Area of Science:

• Biochemistry
• Nanotechnology
• Molecular Diagnostics

Background:

• Human telomerase is over-expressed in malignant cancer cells.
• Accurate detection of telomerase activity is vital for cancer diagnosis and research.
• Current detection methods require further improvement in sensitivity and specificity.

Purpose of the Study:

• To develop a novel, sensitive, and specific colorimetric method for detecting telomerase activity.
• To utilize convertible DNA ends-based silver nanoprobes for this purpose.
• To enable visual distinction between cancer and normal cells based on telomerase activity.

Main Methods:

• Constructed silver nanoprobes (AgNPs) by modifying telomerase substrates (TS) with complementary sequences.
• Utilized the coordination between cytosines and AgNPs to form double-stranded DNA on the nanoparticle surface.
• Observed changes in AgNP dispersity and solution color (yellow to gray) based on telomerase activity and salt-induced aggregation.

Main Results:

• Telomerase activity elongated TS, converting blunt DNA ends to dangling ends, enhancing probe stability and preventing aggregation (yellow color).
• Inactive telomerase resulted in salt-induced aggregation of blunt-ended probes (gray color).
• Achieved a detection limit equivalent to 1 cell/μL of telomerase activity, with clear visual distinction between cancer and normal cell extracts.

Conclusions:

• Developed a reliable and convenient colorimetric method for quantifying telomerase activity using silver nanoprobes.
• The "blunt-dangling" DNA ends conversion mechanism offers a novel approach for biosensing.
• This strategy holds promise for biochemical research and clinical cancer diagnosis.