title: Nanoimaging: photophysical and pharmaceutical characterization of poly-lactide-co-glycolide nanoparticles engineered with quantum dots.
abstract: Quantum dots (QDs) and polymeric nanoparticles (NPs) are considered good binomials for the development of multifunctional nanomedicines for multimodal imaging. Fluorescent imaging of QDs can monitor the behavior of QD-labeled NPs in both cells and animals with high temporal and spatial resolutions. The comprehension of polymer interaction with the metallic QD surface must be considered to achieve a complete chemicophysical characterization of these systems and to describe the QD optical properties to be used for their unequivocal identification in the tissue. In this study, by comparing two different synthetic procedures to obtain polymeric nanoparticles labeled with QDs, we investigated whether their optical properties may change according to the formulation methods, as a consequence of the different polymeric environments. Atomic force microscopy, transmission electron microscopy, confocal and fluorescence lifetime imaging microscopy characterization demonstrated that NPs modified with QDs after the formulation process (post-NPs-QDs) conserved the photophysical features of the QD probe. In contrast, by using a polymer modified with QDs to formulate NPs (pre-NPs-QDs), a significant quenching of QD fluorescence and a blueshift in its emission spectra were observed. Our results suggest that the packaging of QDs into the polymeric matrix causes a modification of the QD optical properties: these effects must be characterized in depth and carefully considered when developing nanosystems for imaging and biological applications.
authors.affiliation: National Enterprise for nanoScience and nanoTechnology, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy. Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pederzoli
authors.forename: B
authors.initials: B
authors.lastname: Ruozi
authors.forename: E
authors.initials: E
authors.lastname: Pracucci
authors.forename: G
authors.initials: G
authors.lastname: Signore
authors.forename: Mauro
authors.initials: M
authors.lastname: Zapparoli
authors.forename: F
authors.initials: F
authors.lastname: Forni
authors.forename: M A
authors.initials: MA
authors.lastname: Vandelli
authors.forename: G
authors.initials: G
authors.lastname: Ratto
authors.forename: G
authors.initials: G
authors.lastname: Tosi
mesh_terms: D000818:Animals; D019344:Lactic Acid / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D050997:Nanomedicine; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D061848:Optical Imaging / Q000379:methods; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols