Synthesis of Fe 3 O 4 /ZnO Core-shell Nanoparticles for Photodynamic Therapy Applications
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1257-O06-04
Synthesis of Fe3O4/ZnO Core-shell Nanoparticles for Photodynamic Therapy Applications Juan C. Beltran-Huarac1, Surinder P. Singh2, Maharaj S. Tomar1, Sandra Peña3, Luis Rivera3, Oscar J. Perales-Perez2 1
Department of Physics, University of Puerto Rico, Mayagüez Engineering Science & Materials, University of Puerto Rico, Mayagüez 3 Department of Chemistry, University of Puerto Rico, Mayagüez 2
ABSTRACT The use of nanoparticles as carriers of photosensitizer (PS) molecules for photodynamic therapy (PDT) has attracted much interest on core-shell nanosize structures. Herein, we used a simple aqueous solution method to synthesize Fe3O4/ZnO core-shell nanoparticles. X-ray diffraction (XRD) analyses showed the presence of well defined peaks corresponding to Fe3O4 and ZnO in as-synthesized nanocrystals. Vibrating sample magnetometer (VSM) measurements showed that these nanoparticles exhibited superparamagnetic behavior of the core with no coercivity nor remanence. X-ray photoelectron spectroscopy (XPS) analyses revealed the presence of Zn1/2 and Zn3/2 species on the surface of nanocrystals. Photoluminescence measurements showed excitonic emission of ZnO co-existing with a weak and broad defectrelated green emission at room temperature. The generation of singlet oxygen was monitored via the photooxidation of diphenyl-1,3-isobenzofuran (DPBF) with different light sources, followed by absorption spectroscopy at 409 nm. The capability of synthesized nanoparticles to generate singlet oxygen has also been verified. INTRODUCTION Superparamagnetic iron oxide nanoparticles due to their unique magnetic properties at nanoscale that are highly dependent on size and shape possess promising applications in biomedical science and sensors [1]. Likewise, zinc oxide is an important wide band-gap II-IV semiconductor with direct band-gap of 3.37 eV at room temperature having versatile applications in optoelectronic devices, electrical devices and biomedical sciences [2]. Pursuing multifunctionality, core-shell heterostructured nanoparticles have become an active area of research because of their unique chemical and physical properties; however, the choice of the proper core and shell material depend on the nature of application [3]. In particular, nanocomposite particles consisting of magnetic cores and luminescent shells are receiving increasing attention in biomedical and biological applications such as magnetic separation and detection of cancer cells, bacteria and viruses [4]. The highly efficient luminescence properties of CdSe quantum dots have shown their promises in various field of biology; however, their cytotoxicity is a major concern that limits the use of these visible photoluminescent emitting nanocomposites. Recently, Hong et al. have synthesized Fe3O4/ZnO nanoparticles and studied their optical properties [5]. The photocatalytic activity of these nanoparticles also indicates towards their capability of producing reactive oxygen species (ROS) as suggested by Joshi et al. [2]. Yi et al. have synthesized γ-Fe2O3–Cd
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