Tuesday, October 6, 2015

SPIO-loaded PLGA-RGD nanoparticles used for dual cancer targeting by integrin binding and magnetism.

PolySciTech Division of Akina, Inc. (www.polyscitech.com) provides a wide array of polymers including PLGA and related activated precursors such as PLGA-NHS. These kinds of polymers have been utilized to develop a theranostic targeted nanoparticle. Theranostics is a relatively new approach to cancer in which the targeting strategy serves to both diagnose the cancer (by fluorescence or radio-opacity) as well as treat cancer (by delivery of chemotherapeutic agents). Researchers in Belgium recently developed such targeted nanoparticles by using two different targeting strategies. The first of which was to conjugate RGD labelling peptide onto the exterior of the PLGA nanoparticle so that it can preferentially bind to cancer cells by targeting the αvβ3 integrin, an integrin involved in angiogenesis that is overexpressed on cancer cells. Additionally the particles were loaded with super-paramagnetic iron oxide (SPIO) which renders the particles magnetic. By simply placing a magnet near the tumor, the particles can be attracted to the magnet. SPIO serves another diagnostic purpose in that it serves as a MRI contrast agent allowing the tumor to be visualized by this technique. The particles were also loaded with chemotherapeutic paclitaxel and the system analyzed extensively. You can read about this work here: Danhier, Fabienne, Pierre Danhier, Nathalie Schleich, Chrystelle Po, Sophie Laurent, Pierre Sibret, Christine Jeroˆme, Vincent Poucelle, Bernard Gallez, and Veronique Preat. "Tumor Targeting by RGD-Grafted PLGA-Based Nanotheranostics Loaded with Paclitaxel and Superparamagnetic Iron Oxides." (2015). http://link.springer.com/protocol/10.1007/7653_2015_43

“Abstract: Theranostic nanoparticles have the potential to revolutionize cancer diagnosis and therapy. Many groups have demonstrated differential levels of tumor growth between tumors treated by targeted or untargeted nanoparticles; however, only few have shown in vivo efficacy in both therapeutic and diagnostic approach. Herein, we first develop and characterize dual-paclitaxel (PTX)/superparamagnetic iron oxide (SPIO)-loaded PLGA-based nanoparticles grafted with the RGD peptide, for a theranostic purpose. Second, we compare in vivo different strategies in terms of targeting capabilities: (1) passive targeting via the EPR effect, (2) active targeting of αvβ3 integrin via RGD grafting, (3) magnetic guidance via a magnet placed on the tumor, and (4) the combination of the magnetic guidance and the active targeting of αvβ3 integrin. In this chapter, we present the general flowchart applied for this project: (1) the polymer and SPIO synthesis, (2) the physicochemical characterization of the nanoparticles, (3) the magnetic properties of the nanoparticles, and (4) the in vivo evaluation of the nanoparticles for their therapeutic and diagnosis purposes. We employ the electron spin resonance spectroscopy and magnetic resonance imaging to both quantify and visualize the accumulation of theranostic nanoparticles into the tumors. Keywords: PLGA-nanoparticles SPIO Paclitaxel Cancer therapy Magnetic resonance imaging Tumor targeting Nanotheranostic”
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