SERS of Dopamine: Computational and experimental studies

Area of Science:

• Computational Chemistry
• Spectroscopy
• Materials Science

Background:

• Dopamine is a crucial neurotransmitter with implications in various physiological and pathological processes.
• Sensitive detection methods for Dopamine are essential for clinical diagnostics and research.
• Surface-Enhanced Raman Spectroscopy (SERS) offers high sensitivity for molecular detection.

Purpose of the Study:

• To computationally investigate the interaction between Dopamine and silver clusters (Agn, n=1-4).
• To explore the potential of these interactions in enhancing Dopamine's Raman signal for SERS applications.
• To fabricate and test SERS substrates for Dopamine detection.

Main Methods:

• Density Functional Theory (DFT) calculations were performed to simulate Raman spectra and analyze electronic properties.
• Key parameters such as global electrophilicity index (ω), polarizability (α0), and polarizability anisotropy (Δα) were calculated.
• Complex stability was assessed using charge transfer, stabilization, and interaction energies.
• Molecular Electrostatic Potential (MESP) surfaces were analyzed.
• SERS substrates were fabricated by laser sintering silver nanoparticle paste onto fused silica.

Main Results:

• Calculated Raman spectra indicated increased intensity with a higher number of silver atoms in the clusters.
• Electronic properties and stability analyses supported the observed Surface-Enhanced Raman Spectroscopy (SERS) effect.
• The fabricated SERS substrates demonstrated the ability to detect Dopamine at concentrations as low as 1 μM.

Conclusions:

• Silver clusters significantly enhance the Raman activity of Dopamine, making it suitable for SERS detection.
• Computational insights correlate well with experimental observations, validating the SERS mechanism.
• The developed SERS substrates provide a sensitive and effective platform for Dopamine detection.