Sialic Acid-Functionalized Gold Nanoparticles for Sensitive and Selective Colorimetric Determination of Serotonin

Area of Science:

• Nanotechnology
• Biochemistry
• Analytical Chemistry

Background:

• Serotonin is a crucial neurotransmitter with implications in various physiological and pathological processes.
• Accurate and sensitive detection of serotonin is vital for research and clinical diagnostics.
• Existing detection methods may lack sensitivity, selectivity, or ease of use for certain applications.

Purpose of the Study:

• To develop a novel, highly sensitive, and selective colorimetric method for serotonin detection.
• To utilize gold nanoparticles functionalized with sialic acid for visual serotonin quantification.
• To assess the method's performance in terms of selectivity, dynamic range, limit of detection, response time, and applicability to biological samples.

Main Methods:

• A colorimetric assay was designed using sialic acid-anchored gold nanoparticles (SA-AuNPs).
• The method relies on serotonin-induced aggregation of SA-AuNPs, leading to a visible color change (red to blue) and a red shift in absorbance.
• Interference studies were conducted with structurally similar compounds and potential biological contaminants. Recovery assays were performed on processed human plasma samples.

Main Results:

• The developed method demonstrated high selectivity for serotonin, with no significant interference from dopamine, epinephrine, l-tyrosine, glucosamine, galactose, mannose, oxalic acid, or l-tryptophan.
• A wide linear dynamic range (0.05–1.0 μM) and a low limit of detection (0.02 μM) were achieved, outperforming existing colorimetric sensors.
• The assay exhibited a rapid response time of 5 minutes and successful serotonin recovery (90.5–104.2%) in processed human plasma, indicating clinical potential.

Conclusions:

• The novel SA-AuNP-based colorimetric method provides a sensitive, selective, and visually detectable approach for serotonin quantification.
• The method's robustness against interfering substances and its successful application in biological samples highlight its potential for clinical diagnostics and biochemical research.
• This nature-inspired approach offers a promising alternative to conventional serotonin detection techniques, particularly where instrumentation is limited.