Characterization of a tethering system for biosensor applications

The immobilization of brain dopamine receptors on a solid support can represent an appealing strategy for the realisation of a sensing element for dopamine and dopaminergic drugs. Brain dopamine receptors are the primary targets in the treatment of schizophrenia, Parkinson’s disease, and Huntington’s chorea. Our final goal is the realization of an optical biosensor which allows a parallel quantitative analysis, with different receptors, of neurotransmitters and different drugs related to the pathologies of interest. The active layer will be constituted by dopaminergic receptors immobilized in biomimetic membranes. The need to preserve the biological activity of neuroreceptors is dramatically important and requires that the protein of interest has to be reconstituted into lipid bilayers tethered to a suitable sensor surface. Such processes involve the fabrication of artificial tethered bilayer (biomimetic membranes), the immobilization of the receptors in these membranes by soft lithography methods. The characterization of the active layer was performed by scanning probe techniques, in order to test its quality and integrity, and by suitable optical experiments involving the intrinsic fluorescence of the neurotransmitter (or neuroreceptors), or the signal emitted by specific fluorescent ligands