Khohinur Hossain
Università Ca Foscari Venezia, Italy
Title: Functionalization of mesoporous zirconia nanoparticles with bis-phohphonic acids for successful tailoring of the surface properties: In depth investigation of the process
Biography
Biography: Khohinur Hossain
Abstract
The design of surface modification of inorganic materials has been focused on silica-based materials for a long period. However, due to the limited chemical and physical stability of such materials, interest increasingly shifted to the use of ceramics such as Zirconia (ZrO2) and Titania (TiO2). Zirconia is chemically inert, biocompatible with good mechanical and thermal properties for in vivo biomedical applications. Nanoparticles (NP) for biomedical applications must maintain colloidal stability under physiological conditions and NP carrying a payload should limit a premature release of the guest before reaching the target organ. So, chemical modification of the NP surface is essential for specific interactions with biomolecules of interest. In particular, the functionalization of zirconia NP is a much less developed field compared to silica NP. The latter is based on the use of a wide range of commercially available tris-alkoxy-silane derivatives, while for zirconia a lack of suitable functionalization methods is present and silane chemistry is not suitable in this case. The purpose of this study is to develop a new functionalization method specific for zirconia NPs based on the synthesis and application of bis-phosphonic acids (BPs) bearing different functional groups as a chelating unit that can more efficiently bind the zirconia surface and impart unique and tailored properties to the NP. Bisphosphonates (P-C-P) are biological analogues of enzymatic hydrolysable pyrophosphates (P-O-P) whereas the P-C-P group is resistant not only to chemical but also to enzymatic hydrolysis. With solution 1H-NMR we followed the loading of the BP on the zirconia surface at different pH conditions and with thermogravimetric analysis (TGA) we investigated the amount of organic modification on the surface. With Zeta potential measurements we correlated the loading of BP on the NPs with the good anti-aggregation properties to the NP. Future applications of these modified NPs will be the loading of drugs for in vitro test of release.