Signal-on photoluminescent detection of dopamine with carbon dots-MnO2 nanosheets platform based on inner filter effect

Development of new methods for dopamine (DA) assay has attracted continuous attention because it serves a vital role in clinical treatment of neurological diseases such as depression, schizophrenia, and Parkinson's disease. Herein, we design a carbon dots (CDs)-MnO 2 nanosheets platform for rapid and sensitive detection of DA in pharmaceutical products. The photoluminescence of CDs can be quenched by MnO 2 nanosheets via inner filter effect (IFE) because the absorption of MnO 2 nanosheets fully covered the excitation and emission bands of CDs. However, DA can transform MnO 2 nanosheets into Mn 2+ ions, resulting in the elimination of the IFE and recovery of the photoluminescent signal. This sensing platform shows a selective and sensitive response to DA in the range of 1–30 μM, with a detection limit of 100 nM. The presented IFE-based strategy gives a new insight on development of label-free, selective and sensitive optical methods for drug assay.