Multiple signal amplified electrochemiluminescent immunoassay for brombuterol detection using gold nanoparticles and polyamidoamine dendrimers-silver nanoribbon

- A multiple signal amplification ECL immunosensor of eco-friendly CdSe QDs for brombuterol determination was developed.
- Besides substrates, AuNPs and PAMAM-SNR were creatively used to accelerate the electron transport between electrode and QDs.
- SNR-PAMAM with numerous amino groups also could be employed to bond abundant actived QDs to amplify ECL signal.
- Competitive immunoassay was performed with ECL to detect small molecules of brombuterol.
- It provided a method for detecting Brom and enlarged the usage of QDs, AuNPs and SNR-PAMAM in ECL biosensing.

Electrochemiluminescent (ECL) immunosensor with multiple signal amplification was designed based on gold nanoparticles (AuNPs), polyamidoamine dendrimers (PAMAM) and silver-cysteine hybrid nanoribbon (SNR). Low toxic l-cysteine capped CdSe QDs was chosen as the ECL signal probe. To verify the proposed ultrasensitive ECL immunosensor for β-adrenergic agonists (β-AA), we detected Brombuterol (Brom) as a proof-of-principle analyte. Therein, AuNPs as the substrate can simplify the experiment process, accelerate the electron transfer rate, and carry more coating antigen (Ag-OVA) to enlarge ECL signal. On one hand, SNR on the surface of electrode can avoid the aggregation of AuNPs, and SNR-PAMAM-AuNPs also can be acted as a good accelerator for electron transfer. On the other hand, PAMAM (16 -NH2) functionalized SNR (SNR-PAMAM) with numerous amino groups could be employed to bond abundant actived QDs to further amplify ECL signal. The new immunosensor can offer a simple, reliable, rapid, and selective detection for Brom, which have a dynamic range of 0.005-700 ng mL−1 with a low detection limit at 1.5 pg mL−1. The proposed biosensor will extend the application of nanomaterials in ECL immunoassays and open a new road for the detection of Brom and other β-AA in the future.