Highly selective luminescent nanostructures for mitochondrial imaging and targetingElectronic supplementary information (ESI) available: Additional TEM micrographs, fluorescence and UV-Vis absorbance spectra of silica coated QD nanoparticles and TSPO ligand. See DOI: 10.1039/c5nr08139d

• Main Authors: Fanizza, E, Iacobazzi, R. M, Laquintana, V, Valente, G, Caliandro, G, Striccoli, M, Agostiano, A, Cutrignelli, A, Lopedota, A, Curri, M. L, Franco, M, Depalo, N, Denora, N
• Format: Journal Article
• Published: 05.02.2016
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr08139d

Here a luminescent hybrid nanostructure based on functionalized quantum dots (QDs) is used as a fluorescent imaging agent able to target selectively mitochondria thanks to the molecular recognition of the translocator protein (TSPO). The selective targeting of such an 18 kDa protein mainly located in the outer mitochondrial membrane and overexpressed in several pathological states including neurodegenerative diseases and cancers may provide valuable information for the early diagnosis and therapy of human disorders. In particular, the rational design of amino functionalized luminescent silica coated QD nanoparticles (QD@SiO 2 NPs) provides a versatile nanoplatform to anchor a potent and selective TSPO ligand, characterized by a 2-phenyl-imidazo[1,2- a ]pyridine acetamide structure along with a derivatizable carboxylic end group, useful to conjugate the TSPO ligand and achieve TSPO-QD@SiO 2 NPs by means of a covalent amide bond. The colloidal stability and optical properties of the proposed nanomaterials are comprehensively investigated and their potential as mitochondrial imaging agents is fully assessed. Sub-cellular fractionation, together with confocal laser scanning fluorescence microscopy and co-localization analysis of targeted TSPO-QD@SiO 2 NPs in C6 glioma cells overexpressing the TSPO, proves the great potential of these multifunctional nanosystems as in vitro selective mitochondrial imaging agents. A multifunctional hybrid nanostructure based on luminescent QDs and a suitably designed TSPO ligand was used as a bioimaging agent for selective mitochondrial targeting.