Indole-3-acetic acid biosensor based on G-rich DNA labeled AuNPs as chemiluminescence probe coupling the DNA signal amplification

A highly sensitive chemiluminescence (CL) method for detection of phytohormone indole-3-acetic acid (IAA) was developed by using G-rich DNA labeled gold nanoparticles (AuNPs) as CL probe coupling the DNA signal amplification technology. The IAA antibody was immobilized on carboxyl terminated magnetic beads (MBs). In the presence of IAA, antibody labeled AuNPs were captured by antibody functionalized MBs. The DNA on AuNPs is released by a ligand exchange process induced by the addition of DTT. The released DNA is then acted as the linker and hybridized with the capture DNA on MBs and probe DNA on AuNPs CL probe. The CL signal is obtained via the instantaneous derivatization reaction between a specific CL reagent, 3,4,5-trimethoxyl-phenylglyoxal (TMPG), and the G-rich DNA on AuNPs CL probe. IAA can be detected in the concentration range from 0.02 ng/mL to 30 ng/mL, and the limit of detection is 0.01 ng/mL.

Graphical abstractThe detection signal is amplified through G-rich DNA labeled AuNPs as CL probe and released DNA which further acts as a linker. The signal amplification technology provides a detection limit of 0.01 ng/mL for IAA.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The G-rich DNA labeled gold nanoparticles used as CL probe. ► The CL reaction between TMPG and G-rich DNA used for IAA detection. ► The limit of detection is 0.01 ng/mL for IAA.