Application of Chitosan/Fe3O4 Nanocomposite as Biosensor

Abstract

Modified chitosan with metal oxides show a potential application in many areas of research. Accordingly, a model molecule of three chitosan units was modified with Fe3O4 through the chitosan's O-linkage (Cs). The modified structure is supposed to interact with alanine amino acid as a protein structure model. Density functional theory method at B3LYP level was used with 6-31G(d,P) basis set. At this level, the total dipole moment (TDM), the bandgap energy as the difference between the highest and lowest molecular orbital (HOMO/LUMO bandgap). The molecular electrostatic potential (MESP) is mapped at the same level of theory. HOMO/LUMO for Cs was 2.9217 eV modified for Cs/ Fe3O4 to be 0.5919 eV. As far as it interacts with alanine, it became 0.3415 eV, which indicated a sharp decrease in HOMO/LUMO energy. The MESP map of Cs/ Fe3O4 indicated that chitosan's reactivity is improved as the electronegativity increased. These results dedicated Cs/ Fe3O4 as a sensor for the amino acid alanine.