Investigation of the Thermochemiluminescent (TCL)phenomenon as innovative detection technique for(bio)analytical applications: from the synthesis of new TCLcandidates to the realization of TCL-based probes forimmunoassays

Abstract

In the present PhD thesis, thermochemiluminescence (TCL) phenomenum as a new promising tool for development of innovative (bio)analytical detection methods has been investigated. The first part of this work was focused on the synthesis of new TCL candidates, aiming the optimization of the TCL properties in terms of lower decomposition temperatures and higher fluorescence quantum yields of the generated excited fragments. Moreover, through a chemometric approach, both the structural and electronic molecular descriptors for each molecule were analysed and used to elaborate a model able to predict the olefin photooxygenation outcome. Moving forward, the focus was shifted to the realization of TCL-based nanosensors for immunoassay applications. In particular, the fabrication of both molecular and nanometric-scale probes was performed, linking the TCL substrate (1,2-dioxetane) directly to universal biomarker or encapsulating it within a polymeric nanoshell. Concerning the molecular probe, acridin 1,2-dioxetane was functionalized with biotin in order to create a TCL sensor for detection of streptavidin-based targets. TCL process was, then, combined with the semiconductive polymer dots (Pdots) technology to realize ultrabright thermo-responsive nanoparticles able to detect biotinylated compounds of interest. In particular, the FRET mechanism occurring between the polymeric matrix of Pdots and TCL substrate has been exploited to both enhance the light generation and shift the emission towards longer wavelengths. Furthermore, TCL-Pdots were tested in a noncompetitive sandwich-type immunoassay for detection of Immunoglobuline G (IgG). The last part of this work was focused on the realization of a home-made portable device to combine TCL-based detection technique with smartphone technology. All the different items constituting the apparatus have been fabricated exploiting a 3D printing process and acrylonitrile-butadiene-styrene (ABS), as starting material. The device was tailored to the camera of a Nokia Lumia 1020 exploiting, thus, the performance of the complementary Metal Oxide Semiconductor sensor of the smartphone’s camera.