Optical properties of fluorescein-labeled organoclay.
We report the preparation of aminopropyl-functionalized magnesium phyllosilicate (Mg-organoclay) conjugated to fluorescein isothiocyanate (FITC) functionality (FITC-organoclay) by one-pot sol-gel synthesis. The physical characteristics of the Mg- and FITC-organoclays were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), FT-IR and UV-Vis spectrophotometry. X-ray fluorescence and elemental analysis were conducted to confirm the composition of the Mg-organoclay. The FITC-organoclay particles were polydispersed with an average particle size of approximately 50 nm, as determined from SEM images. The XRD patterns of FITC-organoclay exhibited broad peaks and reduced basal d(001) indicating a less condensed and more disordered structure than was observed for Mg-organoclay. The conjugation between FITC- and Mg-organoclay was characterized by FT-IR spectroscopy. Fluorescence excitation and emission spectral data demonstrated the successful conjugation of FITC dye molecules to the Mg-organoclay. The time-resolved fluorescence measurements revealed that FITC had a lifetime of 4.58 ns, whereas the lifetime of FITC-organoclay required a double exponential fit (tau(1,2) = 0.72 and 2.68 ns). As a result, the lifetime of the FITC-organoclay was shorter than that of FITC in ethanol and indicated moderate photostability in the solution state. The cellular uptake of FITC-organoclay in human lung alveolar carcinoma epithelial cells (A549) was quantified and characterized.
Department of Chemical & Biomolecular Engineering (BK 21 Program), KAIST, Daejeon, Korea.
Young-Chul
YC
Lee
Tae-Ho
TH
Lee
Hyo-Kyung
HK
Han
Woon Jung
WJ
Go
Ji-Won
JW
Yang
Hyun-Jae
HJ
Shin
D045744:Cell Line, Tumor; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology; D053758:Nanoparticles / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*
D005456:Fluorescent Dyes; D017640:Silicates; D016650:Fluorescein-5-isothiocyanate