Aptamer-Modified Ultrastable Gold Nanoparticles for Dopamine Detection

Metallic nanoparticles, in particular silver and gold nanoparticles, have been used in various fields for centuries. In the last few decades, their plasmon resonance has made them particularly attractive to biochemists because of their unparalleled optical properties, making them ideal probes for molecular detection. In this article, a new approach to dopamine detection based on ultrastable gold nanoparticles is presented. A dopamine-binding aptamer was used to modify ultrastable gold nanoparticles for the sensitive and selective detection of different concentrations of dopamine without inducing gold nanoparticles aggregation. Indeed, when dopamine binds to the aptamer present at the surface of the gold nanoparticle, the latter exhibits a plasmon shift relative to the dopamine concentration, allowing measurement of its dosage. Besides that, the target molecules can be filtered out to permit nanoparticles reuse. The detection assay showed good linearity between the dopamine concentration and gold nanoparticles' plasmon shift while common interfering molecules, such as ascorbic acid and tyramine, induced no or little plasmon shift.