AuNPs colorimetric sensor for detecting platelet-derived growth factor-BB based on isothermal target-triggering strand displacement amplification

We developed a colorimetric sensor based on gold nanoparticle (AuNP) labels and target-triggered strand displacement amplification (SDA) for the detection of platelet-derived growth factor-BB (PDGF-BB). Upon the target binding, the linear probe conformation was converted into a triple-helix conformation and then a large number of reporter oligonucleotides were produced by SDA. PDGF-BB was then determined by detecting the reporter oligonucleotides using gold nanoparticle labels. The signal output showed a linear relationship for PDGF-BB within the concentration range from 2.0 to 80 nM with a detection limit of 1.1 nM under the optimal conditions. An obvious AuNPs color change was provided when the concentration of PDGF-BB was as low as 4.0 nM. Notably, the assay demonstrated here was free from the interference of other proteins commonly existing in the human breast cancer tissue extracts.