Hybrid self-assembled materials constituted by ferromagnetic nanoparticles and tannic acid: a theoretical and experimental investigation

Hybrid magnetite materials are interesting for both biomedical and catalytic applications due to their well-known biocompatibility, as well as their magnetic and electric properties. In this work we prepared Fe3O4 nanoparticles (NPs) coated with tannic acid (TA), a natural polyphenol, through two different synthetic routes, aiming to understand the influence of TA in the synthesis step and contribute to the development of water-dispersible magnetic materials. The coating process was verified by information obtained from transmission electron microscopy (TEM), zeta-potential and Fourier transform infrared (FTIR) spectroscopy. The incorporation of TA after Fe3O4 NPs production generated spherical NPs smaller than 10 nm, suggesting that TA plays a fundamental role in the nucleation and organization of Fe3O4 NPs. Data from both density functional theory (DFT) and FTIR allowed us to infer that Fe3O4 interacts mainly with the carbonyl groups of TA. Hybrid materials having improved water-dispersibility are very attractive for biomedical applications.The authors acknowledge the financial support from CNPq (470996/2011-0 and 304684/2011-2 projects), CAPES (nBioNet), FAPEPI, MICINN (Spain) for project MAT 2011-25870, and CENAPAD-UFC by availability of computational resources used in the development of theoretical calculations.Peer Reviewe