Colorimetric Sensing System for Neurotransmitter Detection Based on Multi-technologies Architecture

In this work, we propose a device to measure neuro-transmitters in a liquid solution using functionalized ultrastable gold nanoparticles in a multi-system architecture. The instrument is made of heterogeneous technological approach based on an optical, microfluidic and electronic systems synchronized together for the detection of neurotransmitters. The microfluidic system is used to manipulate and mix samples in the sensing vial. It was all designed at our laboratory to be efficient, modular and compact. The optical layout was based on a spectrometer with a grism for the analysis of the liquid sample using plasmonic spectroscopy of the nanoparticles. The layout was designed in a way to be compact but also easy to align during assembly while maintaining a high resolution and wide spectral bandwidth, all based on commercially available components. The electronic embedded system supervises all the subsystems while also communicating with a home-made software for the data gathering and analysis. The system was tested using different solutions of gold nanoparticles and obtained results of their absorption peaks were compared to the results obtained from a commercial instrument. A difference of 8.4 +/- 7 nm was measured between the absorbance peak of gold nanoparticles samples measured with the Cary-50 commercial instrument and our prototype.