Immobilization of bacterial S-layer proteins from Caulobacter crescentus on iron oxide-based nanocomposite: Synthesis and spectroscopic characterization of zincite-coated Fe_2O_3 nanoparticles

摘要

Zinc oxide was coated on Fe_2O_3 nanoparticles using sol–gel spin-coating. Caulobacter crescentus have a crystalline surface layer (S-layer), which consist of one protein or glycoprotein species. The immobilization of bacterial S-layers obtained from C. crescentus on zincite-coated nanoparticles of iron oxide was investigated. The SDS PAGE results of S-layers isolated from C. crescentus showed the weight of 50 KDa. Nanoparticles of the Fe_2O_3 and zinc oxide were synthesized by a sol–gel technique. Fe_2O_3 nanoparticles with an average size of 50 nm were successfully prepared by the proper deposition of zinc oxide onto iron oxide nanoparticles surface annealed at 450℃. The samples were characterized by field-emission scanning electron microscope (FESEM), atomic force microscopy (AFM), powder X-ray diffraction(XRD) and Fourier-transform infrared spectroscopy (FT-IR).