Applications Of Inorganic Nanomaterials In The Determination Of Biological Molecules And Metal Ions

Owing to the unique optical properties, electrical properties and magnetic properties, nanomaterials have been widely applied in the fields of environment, food, biology, medicine, catalysis, etc, and are expected to enter other more fields of research. For those reasons, in this dissertation, we investigate the properties of inorganic nanomaterials (carbon materials and noble metal nanomaterials), with electrocatalytic activity and high biocompatibility, and explored their applications in the detection of biomolecules and metal ions. The main contents are as follows:1. Gold nanoparticles (AuNPs) used for arginine detection. Different from other amino acids, arginine is the only one that contains guanidine group, and has the highest isoelectronic point (pI). At pH 9.62, negatively charged citrate-capped AuNPs are well dispersed because of strong electrostatic repulsion, and the color of the solution is red. In the presence of arginine, however, positively charged arginine (pH<pI) easily induces negatively charged citrate-capped AuNPs aggregation through electrostatic and hydrogen-interactions, resulting in a red to blue color change of the solution. Therefore, a new method is established for the visual determination of arginine. Furthermore, this method can provide satisfactory results for the determination of arginine in injection samples.2. AuNPs used for Hg2+detection. In the absence of Hg2+, imide group of xanthine easily adsorbs onto the surface of AuNPs through Au-N bond and induces aggregation of AuNPs, resulting in a blue color. In the presence of Hg2+, however, Hg2+can specifically bind with xanthine to form xanthine-Hg2+-xanthine complex, which prevents the AuNPs against xanthine-induced aggregation, resulting in a visible color change from blue to red depend on the concentration of Hg2+. Therefore, a new method can be established for Hg2+visual detection. Hg2+in synthetic samples could be detected with the recovery between 96.3% and 101.7%. Compared with other methods that employ thymine-rich DNA, our method is simple, fast, cost-effective.3. Graphene oxide (GO) used for adenosine triphosphate (ATP) detection. Because of the riched-πelectrons, GO can bind with single-stranded DNA (ssDNA) throughπ-πstacking, but can not with double-stranded DNA (dsDNA). Based on the features, we developed a new method for the detection of ATP. The hybrid of ATP aptamer with its fluorescein (FAM)-labelled complementary DNA (FAM-DNA) demonstrated weak affinity for GO, exhibiting strong fluorescence of FAM-DNA. If ATP was presented, however, the strong fluorescence of FAM-DNA got quenched, for the binding of ATP with its aptamer greatly inhibited the hybridization of the aptamer with FAM-DNA and the unhybridized FAM-DNA was adsorbed on the surface of GO. Therefore, a new method is established for the determination of ATP.