An ultrasensitive quantum dots fluorescent polarization immunoassay based on the antibody modified Au nanoparticles amplifying for the detection of adenosine triphosphate

•A new fluorescent polarization immunoassay (FPIA) method for ATP was structured.•The fluorescence polarization method has ultrahigh sensitivity and good selectivity.•The method could be applied for the ATP detection in bioanalysis.

In this work, an ultrasensitive fluorescent polarization immunoassay (FPIA) method based on the quantum dot/aptamer/antibody/gold nanoparticles ensemble has been developed for the detection of adenosine triphosphate (ATP). DNA hybridization is formed when ATP is present in the PBS solution containing the DNA-conjugated quantum dots (QDs) and antibody-AuNPs. The substantial sensitivity improvement of the antibody-AuNPs-enhanced method is mainly attributed to the slower rotation of fluorescent unit when QDs-labeled oligonucleotides hybridize with antibody modified the gold nanoparticle. As a result, the fluorescent polarization (FP) values of the system increase significantly. Under the optimal conditions, a linear response with ATP concentration is ranged from 8 × 10−12 M to 2.40 × 10−4 M. The detection limit reached as low as 1.8 pM. The developed work provides a sensitive and selective immunoassay protocol for ATP detection, which could be applied in more bioanalytical systems.

Graphical abstractA new fluorescent polarization immunoassay (FPIA) method for ATP was structured. The fluorescence polarization method has ultrahigh sensitivity and good selectivity. The method could be applied for the ATP detection in bioanalysis.Figure optionsDownload full-size imageDownload as PowerPoint slide