Yeast powder derived carbon quantum dots for dopamine detection and living cell imaging.

Dopamine (DA) is an important neurotransmitter in the brain of mammals. There is a critical need for fast and sensitive determination approaches to monitor these potential diseases due to various weaknesses in clinical trials of the existing methods for DA detection. DA can effectively quench the fluorescence of carbon quantum dots (CDs) through the inner filter effect and static quenching. In this work, fluorescent yeast CDs (Y-CDs) were prepared via a simple hydrothermal approach of using yeast powder and regarded as the fluorescent nanoprobe to directly monitor the DA concentration. The as-prepared detection platform exhibited excellent sensitivity and selectivity toward DA with a low detection limit of 30 nM and a wide linear range of 0.05-150 μM. Benefiting from these outstanding features, the developed label-free method has been successfully applied for fast DA detection in human serum samples with satisfactory recoveries. Furthermore, it demonstrated that the Y-CDs were well suitable for live cell imaging and showed low toxicity toward MCF-7 cells. Consequently, this work will facilitate the great potential of the versatile Y-CDs in developing biosensors for clinical diagnosis and other biological applications.