Fluorenyl-Loaded Quatsome Nanostructured Fluorescent Probes
Delivery of hydrophobic materials in biological systems, for example, contrast agents or drugs, is an obdurate challenge, severely restricting the use of materials with otherwise advantageous properties. The synthesis and characterization of a highly stable and water-soluble nanovesicle, referred to as a quatsome (QS, vesicle prepared from cholesterol and amphiphilic quaternary amines), that allowed the nanostructuration of a nonwater soluble fluorene-based probe are reported. Photophysical properties of fluorenyl–quatsome nanovesicles were investigated via ultraviolet–visible absorption and fluorescence spectroscopy in various solvents. Colloidal stability and morphology of the nanostructured fluorescent probes were studied via cryogenic transmission electronic microscopy, revealing a "patchy" quatsome vascular morphology. As an example of the utility of these fluorescent nanoprobes, examination of cellular distribution was evaluated in HCT 116 (an epithelial colorectal carcinoma cell line) and COS-7 (an African green monkey kidney cell line) cell lines, demonstrating the selective localization of C-QS and M-QS vesicles in lysosomes with high Pearson's colocalization coefficient, where C-QS and M-QS refer to quatsomes prepared with hexadecyltrimethylammonium bromide or tetradecyldimethylbenzylammonium chloride, respectively. Further experiments demonstrated their use in time-dependent lysosomal tracking. ; This work was supported by the DGI, Spain, "Grants BEWELL CTQ2013-40480-R" and "Mother MAT 2016-80826- R", by AGAUR, Generalitat de Catalunya, "Grant 2014-SGR17", the Networking Research Center on Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), and the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV-2015-0496) through FIP Flowers project. Characterizations of nanovesicles were made at the ICTS "NANBIOSIS", more specifically by the U6 unit of CIBERBBN. The research leading to these results received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/ 2007−2013 under REA grant agreement no. 607721 (Nano2- Fun) A.A. is enrolled in the Materials Science Ph.D. program of UAB. K.D.B. and X.L. acknowledge support from the National Science Foundation (CBET-1517273). ; Peer reviewed