Characterization of Bismuth Trioxide Nanoparticles and Evaluating Binding Affinity with Proteins

Protein-nanoparticle conjugation, or protein-corona, is important for nanomedicine, nano diagnostic, and nano therapy applications. alpha-Bismuth oxide nanoparticles (alpha-Bi2O3 NPs) were prepared from bismuth nitrate powder using the sol-gel method and characterized using various techniques, including Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-VIS-NIR Spectroscopy, and Brunauer-Emmett-Teller (BET). X-ray diffraction studies revealed that NPs are in the alpha phase with a monoclinic structure. The energy band gap, average surface area and crystallite size are 2.81 eV, 2.42 m(2), and 15-106 nm, respectively. Transmission electron microscopy revealed particle size is 32.21 nm, with a d-spacing of 2.529 angstrom. The surface-tovolume ratio is calculated and found to be 2.553x10(6) m (-1). For the first time, a direct protein interaction with NPs was examined with standard proteins such as bovine serum albumin (BSA), carbonic anhydrase, phosphorylase b, and total human serum proteins and analyzed using mass spectroscopy. Proteomic analysis showed that proteins such as BSA, phosphorylase b, and carbonic anhydrase exhibited a strong affinity with Bi2O3 NPs. However, it was found that there was less or no association between Annexin A6, human serum albumin, Zinc finger protein, and Bestrophin-2 with Bi2O3 NPs.