Effectively Determining Dopamine Based on Dopamine Self-polymerization through Fluorescent Method Using Silicon Quantum Dots as Probe.

Dopamine, a catecholamine neurotransmitter found in both neural tissue and body fluids, plays a critical role in brain function. Its distribution in specific brain regions affects the coordination of pituitary endocrine functions and is directly involved in neural activities, making dopamine concentration detection vital. In this study, highly fluorescent silicon quantum dots (silicon nanoparticles: SiNPs) were synthesized and employed as a fluorescent probe for convenient dopamine detection in Tris buffer. This detection mechanism relies on dopamine's self-polymerization, which results in polydopamine absorbing and quenching the fluorescence of SiNPs through a clarified inner filter effect in a concentration-dependent manner. Under optimized experimental conditions, the method demonstrated a robust linear relationship between the fluorescence quenching efficiency of SiNPs and dopamine concentration (C_DA) within the range of 0.5-40 μM. The linear equation was found to be Y = 0.0074 C_DA + 0.0142, with a limit of detection of 0.06 μM. Moreover, the method was successfully applied to detect dopamine in injection solutions and serum samples, offering a sensitive and selective approach for dopamine detection with promising potential for practical applications.