Magnetic and electrically conductive silica-coated iron oxide/polyaniline nanocomposites for biomedical applications.

This work describes the development of novel dual-stimuli-responsive nanocomposites based on silica-coated iron oxide/polyaniline (Si-MNPs/PANI) for biomedical applications. Si-MNPs/PANI nanocomposites were developed via chemical oxidative polymerization of aniline in the presence of Si-MNPs (25 and 50 wt%). Si-MNPs/PANI were obtained both in nanotubular (SPNTs) and granular (SGTs) forms by altering the synthesis parameters such as acid concentration and mixing process. The effects of nanocomposite morphology were evaluated by investigating their chemical, physical and biological properties. Material characterization was comparatively carried out via SEM, TEM, FTIR, XRD, TGA, room temperature VSM, and electrical resistivity measurements. Biological properties were evaluated by indirect in vitro cytotoxicity and in vitro hemocompatibility analyses according to ISO standards. Results indicated that Si-MNPs/PANI nanocomposites exhibited both magnetically and electrically-responsive properties. Magnetization values of Si-MNPs/PANI nanocomposites increased with increasing Si-MNPs content. However, electrical conductivity was inversely proportional to Si-MNPs content. In addition, SGTs represented remarkably higher electrical conductivity (1.1 S/cm) than SPNTs (4.8 × 10 S/cm), but lower saturation magnetization (21 emu/g) compared to SPNTs (27 emu/g). Furthermore, in vitro cytocompatibility and hemocompatibility of the SGTs and SPNTs varied in a dose-dependent manner, suggesting their use in certain doses for biomedical applications. In conclusion, the developed Si-MNPs/PANI, with magnetic sensitivity and electrical conductivity have potential as nanocomposites for utilization in biomedical applications, e.g. biosensing, controlled-drug delivery, bioelectronic systems, tissue engineering and regenerative medicine as active compound. Besides, the selection of the appropriate synthesis protocol allows Si-MNPs/PANI nanocomposites to exhibit superior properties according to the targeted application area.