Mesoporous electromagnetic composite particles: Electric current responsive release of biologically active molecules and antibacterial properties.

Electric current responsive magnetic composite particles are prepared in three steps. In the first step, spherical and mesoporous submicrometer-sized magnetic iron oxide (FeO) core particles are prepared by solvothermal method. Then magnetic FeO particles are functionalized with amine groups using glycine, where the COO- group of glycine formed a bridging bidentate interaction with the hydroxyl groups on FeO particle surface. Finally polyaniline (PAni) is grafted onto the functional FeO surface via in situ seeded chemical oxidative polymerization of aniline. The average size of FeO/PAni composite particles is 418.82 nm with mesoporous surface structure. Electron microscopic images confirmed that PAni pockets are localized on the surface of FeO core particles. The surface composition is further confirmed by Fourier transform IR (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimety (TG) analyses. FeO/PAni composite particles possessed strong paramagnetic property (47.77 emu g). The electrical conductivity of FeO/PAni composite particles (1.46 × 10 S cm) remained in the same order of magnitude as that of reference PAni particles (3.42 × 10 S cm). The release behavior of biologically active molecules such as trypsin (TR), albumin (AL) and p-acetamido phenol (pAP) is studied using low intensity electric current as stimuli to prevent degradation. Depending on the nature, up to ˜ 33-88% of adsorbed biomolecules/drug are released from the electromagnetic FeO/PAni composite particles. Compared to FeO particles, FeO/PAni composite particles exhibited moderate antibacterial property.