Ultrasensitive aggregation-induced electrochemiluminescence sensor for dopamine detection in polymer hydrogel system

The theory of aggregation-induced electrochemiluminescence (AIECL) provides a new method for preparing novel electrochemiluminescence emitters, but the lack of AIECL-based functional nanomaterials seriously hinder its development and application. In this work, Ti3C2Tx MXene-stabilized iridium bis(1, 2-dipheny1-1 H-benzimidazole)(acetylacetonate) [Ir(pbi)2(acac)] with AIECL in polymer hydrogel was prepared for the first time. Due to the large electroactive surface area of Ti3C2Tx MXene, the stabilized Ir(pbi)2(acac) (Ir@MXene) can amplify the ECL signal of the system. The confinement of Ir@MXene into the polyvinyl alcohol (Ir@MXene-PVA) hydrogel increased the local concentration of Ir(pbi)2(acac), which could not only prevent oxides from entering the Ir(pbi)2(acac) nanodots but also limit the vibration to reduce non-radiative transitions of Ir(pbi)2(acac), leading to a distinct AIECL emission. In addition, dopamine (DA) and H2O2 have been used to explore the ECL quenching behavior of Ir@MXene-PVA systems. Based on ECL quenching of Ir@MXene-PVA system by DA, a sensor has been constructed to detect DA in human serum sensitively. The detection range was 0.01-100 nmol/ mL, with a detection limit of 2.0 pmol/mL. This strategy provides an efficient method for the preparation of Ir@MXene-PVA hydrogel with AIECL emission, which may have promising potential in the clinical detection of DA, H2O2, and other biomarkers.