Detection Of Dna Bases Using Fe Atom And Graphene

With the rapid development of science and technology, the research of biological and physical science is gradually rising, especially the research of using the physical method to detect biomolecular. In the field of detecting biomolecular by the physical method, the research of detection of DNA bases plays a crucial role. In this paper, based on the first-principles, using the generalized gradient approximation method of the density functional theory system. We chooses suitable magnetic probe and analyses the properties of magnetic probe detailedly. Finally, we use chosen magnetic probe to detect four bases of DNA molecule(adenine A, thymine T, cytosine C and guanine G). Hope this work can provide a new idea for the detection of DNA molecule.The main content and results of research:1、Using the first principles, the adsorption of metal atoms on the 5 × 5graphene is studied, including stable structure of adsorption, adsorption energy, the density of states and magnetic moment. Among many composite structures, considering the properties of composite structures, the composite structure of Fe atoms and graphene was initially selected as the magnetic probes for the next work. Calculated results show that Fe atoms can steadilyadsorb on the surface of graphene, and the adsorption site on graphene is the center of the six-member ring, named Hellow. Besides, the composite structure of graphene and Fe atom show obvious magnetic moment, and the magnetic moment is about 2.076μB. Although the size of graphene model chosen is different from previous study, the conclusion is consistent. In this part, we analyses various adsorption properties comprehensively, choosing the composite structure of Fe atom and graphene as the magnetic probe.2、Considering the size of DNA bases, we choose the structure of 6 × 6graphene and Fe atom as the probe, and using the first-principles, we choose6 × 6 graphene to adsorb Fe atom and study the stable structure of adsorption, the site of adsorption, the density of states and magnetic moment.The results in this part will provide references for the research of detection of DNA bases.3、Using the first-principles, we use the composite structure of graphene and Fe atom as the magnetic probe to detect four DNA bases.And in this part, we analyses the properties of the composite structures of four DNA bases and magnetic probe, including the stable adsorption site of four DNA bases, adsorption energy, energy band, the electron density difference, energy band, the density of states and magnetic moment. By analysis, it can be found that the stable adsorption site of the four bases is different,but four bases can adsorbed on the probe firmly, since the smallest adsorption energy is also about 1.970 eV. Besides, it can be found thatbecause of the addition of the bases, the original magnetic moment of probe was changed. When bases thymine(T), cytosine(C) or guanine(G)adsorbed on the probe, the magnetic moment of probe disappeared, but when base adenine(A) adsorbed on the probe, the magnetic magnetic of probe only have a little change. Through the significant change of the magnetic moment, we can identify bases adenine(A) from four DNA bases, and we can learn the reason why the adsorption of adenine(A) have a little influence on the magnetic moment of probe by analyzing the density of states.