title: Synthesis and characterization of functionalized magnetic maghemite nanoparticles with fluorescent probe capabilities for biological applications.
abstract: Nanoparticles with innovative optical, chemical, and magnetic properties combined in a single nanoparticle may be useful as biosensors, targeting agents, and therapeutic agents in the biomedical field. This study describes new magnetic nanoparticles (MNPs) containing the fluorescent dye rhodamine isothiocyanate (RITC) covalently encapsulated within the nanoparticles. These nanoparticles have been prepared by nucleation followed by controlled growth of iron oxide layers onto iron oxide/gelatin-RITC nuclei. The formed RITC labeled MNPs (R-MNPs) are of narrow size distribution, exhibit the fluorescent spectrum of RITC, yet are more photostable. Because of the covalent encapsulation of RITC within the MNPs no detectable leakage of the fluorescent dye into the aqueous continuous phase was observed. This manuscript also demonstrates that the surface of the R-MNPs retains similar ligand binding efficiency as the equivalent nonfluorescent MNPs. Specific cell labeling was obtained by incubating glia cells with R-MNPs conjugated to glial cell line-derived neurotrophic factor (GDNF) protein. We further showed that the R-MNPs may be used for pH sensing between the pH range of 5 and 9. This feature may enable the use of the R-MNPs as a pH sensor of animal tissues and cell compartments. Thus, these functional narrow size distribution R-MNPs with both magnetic and fluorescent properties may provide an important research tool for biological sensing.
authors.affiliation: Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel. bennyperlstein@gmail.com
authors.forename: Benny
authors.initials: B
authors.lastname: Perlstein
authors.forename: Tammy
authors.initials: T
authors.lastname: Lublin-Tennenbaum
authors.forename: Inbal
authors.initials: I
authors.lastname: Marom
authors.forename: Shlomo
authors.initials: S
authors.lastname: Margel
mesh_terms: D002460:Cell Line; D004339:Drug Compounding; D005290:Ferric Compounds / Q000737:chemistry* / Q000528:radiation effects; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000528:radiation effects; D005780:Gelatin; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D009457:Neuroglia / Q000187:drug effects; D011437:Propylamines / Q000737:chemistry; D012235:Rhodamines; D013050:Spectrometry, Fluorescence; D013499:Surface Properties
chemical_list: D005290:Ferric Compounds; D005456:Fluorescent Dyes; D051100:Glial Cell Line-Derived Neurotrophic Factor; D011437:Propylamines; D012235:Rhodamines; C000499:ferric oxide; D005780:Gelatin; C027755:rhodamine isothiocyanate; C011649:3-aminopropylphosphonic acid