Type of presentation: Poster

MS-6-P-1820 Polyhedral iron oxide core-shell nanoparticles in a biodegradable polymeric matrix: Preparation, characterization and application in magnetic particle hyperthermia and drug delivery.

Filippousi M.¹, Angelakeris M.², Pavlidou E.², Bikiaris D.³, Van Tendeloo G.¹

¹EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium, ²Solid State Physics Section, Physics Department, AUTH, GR-54124 Thessaloniki, Greece, ³Laboratory of Polymer Chemistry and Technology, AUTH, GR-54124 Thessaloniki, Greece

maria.filippousi@uantwerpen.be

Nanotechnology is at the leading edge of rapidly developing new therapeutic and diagnostic schemes in diverse areas of biomedicine. Different materials from natural to synthetic polymers as well as inorganic materials with variable structural and physical properties are used as building blocks of biomaterials. Recently, a new term ‘theranostics’ is used in order to encompass two distinct definitions which is the combination of therapeutic and diagnostic agents on a single platform. The development of theranostic nanoparticles is emerging as a new form of “smart” nano-materials that may simultaneously monitor and treat diseases. [1]
The aim of the present study is to characterize the polyhedral iron oxide nanoparticles (IOs) and their magnetic properties that can then be used for the encapsulation of the Paclitaxel drug using two different polymer matrices such as PPSu and its block copolymer mPEG-PPSu-mPEG. [2] Both have been chosen because of their excellent biocompatibility and biodegradability and also because they have melting point temperatures close to the body temperature (Tm=42°C and Tm=44°C). This is very essential in case these IOs will be used for combinatory cancer treatment with hyperthermia and drug release and therefore the drug release was studied at 37°C and at 42°C (Figure 1). The encapsulation of iron oxide nanoparticles into a polymer matrix is confirmed by transmission electron microscopy and further corroborated by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) (Figures 2a, b). Energy dispersive X-ray spectroscopy mapping allowed us to determine the presence of the different material ingredients in a quantitative way (Figure 2c). HAADF-STEM tomography proved that the iron oxide nanocrystals consist of well-defined polyhedral structures with multiple facets (Figure 3). The magnetic features were found in good agreement with their structural and morphological features. The high heat capacity, which can be maintained in the nanovehicles of IOs encapsulated in the polymeric matrix, is sufficient to provoke damage of the cancer cells. Therefore, this nanosystem, in which polyhedral magnetic nanoparticles are incorporated in a biocompatible and biodegradable polymeric matrix, can be used as a multifunctional magnetic particle hyperthermia agent together with heat-assisted drug-delivery addressing directly the current theranostic trends.

1.Filippousi et al. International Journal of Pharmaceutics 2013, 448, 221.

2.Filippousi et al. RCS Advances 2013, 3, 24367.

GVT and MF acknowledge funding from the ERC grant N°246791 under the 7th Framework Program (FP7),COUNTATOMS. This work is also performed within the framework of the IAP-PAI.

Fig. 1: Drug release profile pattern of Taxol from the prepared PPSu-IOs and mPEG-PPSu-mPEG-IOs nanoparticles.	Fig. 2: (a) Bright field TEM image of mPEG PPSu-mPEG -IOs (b) HAADF- STEM image of the particles of Figure (a) and (c)HAADF-STEM EDX mapping (C- blue, Fe - green, O-red) of mPEG- PPSu- mPEG –IOs. The scale bar stands for all images.
Fig. 3: (a) and (b) 3D representation of the reconstructed volume of a single iron oxide nanoparticle along different views. The occurrence of different facets is obvious and the shape of iron oxide nanoparticle seems to be that of a rhombicuboctahedron. (c) An orthoslice through the volume. (d) Theoretical model of a rhombicuboctahedron.