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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster: Nanoparticles and Composite Materials
CPP 12.21: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
AFM and physicochemical characterization of Upconversion Nanoparticles — •Heba S. Mohamad1, Peter Nestler1, Harm Wulff1, Stefanie Perfahl2, Patrick Bednarski2, and Christiane A. Helm1 — 1Inst. für Physik, Uni Greifswald, D-17487 Greifswald — 2Inst. für Pharmazie, Uni Greifswald, D-17487 Greifswald
Recently, the development of upconversion nanoparticles (UCNPs) for fluorescence imaging and drug delivery monitoring attracted attention. For biological labeling, cancers diagnosis and detection, NaYFH4O: Yb,Er is a promising candidate. The sequential absorption of two or more photons in the near infrared (NIR) leads to an emission in the visible range. The NaYFH4O:Yb,Er nanoparticles aggregate in water. Therefore their surface is modified using different approaches. Since the upconversion depends strongly on the crystallographic structure of the UCNPs (either cubic or hexagonal), the ratio of both species within an adsorbed layer needs to be optimized to improve the upconversion property. Main goals of this investigation are formation of homogenous and well distributed UCNPs layers, to examine the upconversion properties.
To determine the size of UCNPs, Atomic Force Microscopy (AFM) is used. The crystalline structure is characterized by the X-ray diffraction (XRD) pattern, to correlate optical with crystallographic properties. The absorption properties are determined with UV-Vis absorption spectroscopy. With a 980 nm laser excitation source the upconverting properties are investigated.