Nanoparticelle organiche fluorescenti per il bioimaging: dalla spettroscopia alle applicazioni in vitro ed ex vivo

This thesis focuses on lipid-based and polymer-based fluorescent organic nanoparticles (FONs) labelled with fluorescent dyes. Several advanced optical spectroscopic/microscopic techniques have been applied to the investigation of FONs as a whole and the encapsulated dyes, assessing their interactions in the native environment (typically aqueous suspensions) as well as when in contact with biological samples, such as ex vivo tissues (eyes and skin) and cell cultures. The thesis is organized into four chapters: Chapter 1, 2 and 3 present the preparation, spectroscopic characterization, and evaluation of the bioimaging capabilities of different FONs families exhibiting increasing complexity. In Chapter 1, self-folded unimer micelles derived from an amphiphilic random copolymer loaded with a simple hydrophobic fluorophore are discussed. Chapter 2 concerns the encapsulation of two different cyanine dyes into common polymeric or lipidic micelles, assessing the presence of FRET phenomena in the system. In Chapter 3, Quatsomes, a class of non-liposomial vesicles with an elaborate supramolecular structure are studied, by investigating the labelling with multiple fluorophores characterized by different physico-chemical properties or targeted surface functionalization. Chapter 4 collects the results obtained by combined spectroscopic and microscopic investigations of NPs specifically designed for drug delivery. In this context, the images and spectroscopic data retrieved from two-photon microscopy proved to be of major support to address the nanocarriers’ fate inside the tissues and corroborate quantification data concerning their permeation and retention. The research work presented in this thesis marks a significant advancement in the exploration of phenomena and nanomaterials for bioimaging applications.