Synthesis and characterization of CaCO3-biopolymers hybrid nanoporous microparticles for cancer damaged bone therapy

V.E. BOSIO; M.CACICEDO; I. LEON; T. BEUVIER; B. CALVIGNAC; F. BOURY; GR CASTRO

Rodas

Congreso; NANO2012 International Conference on NanoStructured Materials; 2012

International Nano Society

Doxorubicin (Dox) is used in the treatment of breast, lung, ovarian and sarcoma among other cancers. However, Dox is highly toxic and can cause severe side effects in non-targeted tissues. The convergence of two strategies such as controlled release and specific cell targeting will provide new pharmacological approach to novel cancer therapies. In this way, folic acid is one of the most common cellular markers because of enhanced receptor expression in most of cancer cells. The aim of the present work is the development of an hybrid nanoporous micro particle (hNPs) carrier based on biopolymers and calcium carbonate containing folic acid for targeting and Dox as chemotherapeutic agent. Biopolymers, containing or not Dox, were used for the precipitation of calcium carbonate forming hNPs. In preliminary experiments, interaction between Dox and 12 biopolymers: hyaluronic acid, three pectins types, three carragenines types (Car), two modified carragenines carboxymethil-Carλ (CM-Carλ) and carboxymethil-Carλ-FolicAcid (CM-Carλ-FA) synthesized in our laboratory were studied. Dox loading and release were followed by spectrofluorometry under physiological conditions and revealed that the Car-hNPs showed higher loading (up to 95%), and CM-Carλ-FA hNPs system showed the best loading capabilities. hNPs structural analysis were performed using FTIR, Raman and XRD spectroscopies. XRD analysis showed about 70/30% vaterite/calcite in biopolymer absence, and up to 95 % vaterite depending on the biopolymer type. SEM images revealed that all types of hNPs were approximately spherical in shape, porous and with an average diameter 1?5μm, and the smallest synthesized particles were Car-hNPs systems (2μm), even compared with the CaCO3 MPs. In order to determine the presence of the biopolymer blended into the matrices, biopolymers derivatized with fluorescent probes were synthesized. Fluorescence microscopy revealed the presence of biopolymers (with/without Dox) incorporated to inorganic matrices and confirmed by FTIR (SOLEIL-Synchrotron). In addition, the presence of the biopolymer increases the specific surface area of the material up to 9 folds (measured by BET method was equal to 26.6 m2g-1) in CM-Carλ-hNPs. Nanostructured-porous surface was found in all the cases, and the CM-Carλ-hNPs porous size was about 20nm (BJH adsorption average). The hNPs anticancer activity was tested in human osteosarcoma cell line MG-63 (ATCC CRL-1427) showing 13 and 100 % cell viability in presence of CM-Carλ-FA-hNPs with or without Dox respectively by Crystal Violet assay after 24hs of incubation.