Alexandru Mihai Grumezescu*, Anton Ficai, Denisa Ficai, Gentiana Prdean, Mariana Carmen Chifiriuc: Polymeric magnetic silica microspheres as a drug loader for antimicrobial delivery substances. Digest Journal of Nanomaterials and Biosctructures, 7(4):1891-1896, 2012.
Na2SiO3 was used as surface modification agent of magnetic dextran microspheres. The composition and morphology of treated magnetic polymer microspheres were characterized by Scanning Electronic Microscopy (SEM), Fourier Transform Infrared Spectra (FT-IR) and powder X-ray Diffraction (XRD). The antimicrobial property was evaluated using antibiotic susceptibility on S. aureus ATCC 25923 and P. aeruginosa ATCC 27853 strains. By analyzing the FT-IR spectrum, the stretching band characteristic of the silica pattern is observed. The magnetite was identified in the sample as the only one crystalline phase. Silica could not be identified by the XRD due to its amorphous nature. The SEM micrographs of polymeric magnetic silica microspheres reveal that they are presenting as well shaped spheres with a rather rough surface. The size of the magnetic microspheres ranges between 50 and 80 μm. The in vitro assay of the inhibitory activity of different antibiotics on the bacterial growth in the presence of polymeric magnetic silica nanocomposites demonstrated the improvement of the antimicrobial activity of some antibiotics in the presence of composite particles, which could act as a drug delivery system for microbial cells targeting and infectious diseases therapy.