SERS –tweezers enhanced by electro-thermo-plasmonic flow

Direct quantification of dopamine neurotransmission is one of the unsolved problems that engaged scientific minds for the last fifty years.

Such quantification is an extremely important tool to understand the underlying pathways that promote neurodegenerative diseases like Alzheimer's and depression.

Since dopamine is secreted only in micro-molar quantities, a novel signal-amplification technique is required to be able to appropriately quantify its concentration.

To meet the challenge, we propose a multidisciplinary research program comprised of simultaneous measurements from laser tweezer Raman spectroscopy and fluorescence emission spectroscopy.

Our proposal is based on the strong plasmonic interaction between graphene oxide nanosheets and aptamer functionalized gold nanoparticles, which increases the local intensity of the electromagnetic field to an extent that minute changes in ambient dielectric constant due to variations in the concentration of dopamine could bring about a perceptible signal.

In the suggested scheme, we will use optical tweezers to place a gold nanoparticle dimer close to the surface of a graphene oxide sheet, and their hybridization will give rise to very strong electromagnetic fields able to dramatically increase the optical emission from dopamine.

Moreover, we will increase the local concentration of molecules with electrothermoplasmonic flow towards the sensing area.

The SERSET project will be carried out in the Nanoparticle Trapping Lab at the University of Granada, where a state-of-the-art setup combining optical tweezers and confocal Raman spectroscopy is available. A microfluidic chip and theoretical calculations will be carried out in the group of Prof. Romain Quidant at ETH Zurich during the planned secondments.

The candidate has a strong background in nanoparticle synthesis, plasmonics, and computational modelling, which will be combined in the present proposal to bring about a new technology able to quantify dopamine secretion.