Selective dopamine detection using the Pictet–Spengler reaction for surface-enhanced Raman scattering

Researchers have developed a novel method for the selective and sensitive detection of dopamine using the Pictet–Spengler reaction in conjunction with surface-enhanced Raman scattering (SERS), addressing longstanding challenges in the direct quantification of dopamine in biological fluids.

The team was from the Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, School of Material and Energy, Guangdong University of Technology, Guangzhou, China, and led by Kunle Li alongside colleagues Xinyu Zheng, Jiancheng Feng, Xing Feng and Yu Zhao.

Dopamine presents difficulties for direct detection via SERS due to its low Raman cross section and the chemical complexity of physiological samples. To overcome these issues, the research team utilised the Pictet–Spengler (P–S) reaction in combination with SERS, introducing a new chemical strategy to enhance selectivity and sensitivity.

The method involves the synthesis of aldehyde-modified layered double hydroxide, which enables dopamine molecules to be anchored via the P–S reaction. This reaction is highly specific to dopamine, thereby improving selectivity by mitigating interference from structurally similar molecules. Silver nanoparticles functionalised with 4-mercaptophenylboronic acid serve as SERS probes, allowing for indirect quantification of dopamine.

The detection technique exhibited excellent analytical performance, achieving a linear response across a concentration range of 10⁻⁵ to 10⁻¹⁰ mol·L⁻¹, with a limit of detection as low as 9.91 × 10⁻¹² mol·L⁻¹ (signal-to-noise ratio = 3). The method also proved effective in complex biological environments, including simulated urine and cerebrospinal fluid, underscoring its potential for clinical application in the diagnosis and monitoring of neurological disorders.

For further reading please visit: 10.1021/acs.analchem.5c01454