Original Articles

Enzyme-free, Colorimetric DNA Detection System Powered by Autocatalytic Assembly Circuits and G-quadruplex DNAzymes

Abstract

Objectives: To develop an enzyme-free colorimetric DNA detection system combining autocatalytic assembly circuits with G-quadruplex DNAzymes for highly sensitive and visual DNA identification.

Methods: The platform utilized toehold-mediated strand displacement (TMSD) integrated with autocatalytic hairpin circuits and a G-quadruplex DNAzyme. Buffer conditions, hemin concentration, temperature, and reaction time were optimized. Spectrophotometric detection at 416 nm was employed, and NUPACK software was used for oligonucleotide design validation.

Results: The optimized system exhibited a detection limit as low as 31 pM. Clear electrophoretic band patterns confirmed correct structure formation. The system showed high reproducibility, sensitivity, and a visible signal without enzymatic components.

Conclusions: This detection method is simple, cost-effective, and highly sensitive, with potential for point-of-care diagnostics, food safety testing, and environmental monitoring. The enzyme-free nature, label-free operation, and modular design make it adaptable to other nucleic acid targets.   

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IssueVol 3 No 1 (2025) QRcode
SectionOriginal Articles
Keywords
DNA Nanotechnology DNAzyme TMSD Colorimetric Technique
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How to Cite
1.
Davood R, Ravan H, Shahram S. Enzyme-free, Colorimetric DNA Detection System Powered by Autocatalytic Assembly Circuits and G-quadruplex DNAzymes. ABI. 2025;3(1):36-45.