Silver nanoparticle@DNA tetrahedron-based colorimetric detection of HIV-related DNA with cascade strand displacement amplification

DNA tetrahedron-modified silver nanoparticles (AgNPs) were achieved via amino-silver chemistry for the first time and were applied as a colorimetric biosensor for detecting HIV-related DNA. Target DNA initiated strand displacement polymerization and nicking endonuclease-aided cycles were involved to link DNA tetrahedron-modified AgNPs, reporting colorimetric responses. This developed method showed excellent specificity and sensitivity. A wide linear range from 1 to 15 000 nM was achieved with a limit of detection of 0.84 nM. Moreover, it was successfully applied to determine DNA in blood serum samples.