A novel nanosponge-hydrogel system-based electrochemiluminescence biosensor for uric acid detection.

In this work, a highly efficient electrochemiluminescence (ECL) biosensor was developed based on the nanosponge-hydrogel system for uric acid (UA) detection. First, the nanosponge consisted of polylactic acid glycolic acid (PLGA) nanoparticles immobilized with MoS2 quantum dots (QDs) and urate oxidase (UAO). The marked loading capability of PLGA nanoparticles enables loading many biomolecules and QDs for the specific recognition of UA. Urate oxidase on the nanosponge can catalyze UA to generate H2 O2 in situ, which further triggers the ECL signal for the MoS2 QDs. Furthermore, the biocompatible acrylamide-based hydrogel not only effectively retained the functionalities of the chimeric nanosponge-hydrogel, but also provided structural integrity and engineering flexibility on the electrode for ECL sensing applications. In addition, there were many ester groups and amide bonds in the nanosponge-hydrogel structure. Therefore, many electron can be excited in the ECL process due to the large number of lone electron pairs on oxygen and nitrogen atoms. This resulted in a seven-fold ECL enhancement of the MoS2 QDs. Finally, the nanosponge-hydrogel structure-based ECL biosensor was successfully used in real clinical serum assays. This showed a good analytical performance for UA detection (100-500 μmol/L) with a limit of detection of 20 μmol/L.