Modifacation And Metal Ion Detection Applications Of Gold Nanoparticles

Gold nanoparticles show promising applications in the field of molecular biology and R&D of biological sensors. It's applications in biochemistry have been a hot topic these years. Lead is very harmful to human and it's very important to develop sensitive and robust analytical approaches for sensing of Pb²⁺. Biomolecules have been the potential building blocks and gold nanoparticles can conjunct to amino acids and peptides, which is fundamental to the application of gold nanoparticles in biochemistry and medicine.Firstly, aiming to overcome the irreversible aggregate of gold nanoparticles in electrolyte solutions, the effect of DNA modification on the gold nanoparticles'stability in presence of sodium ions was investigated, through the characterization of UV-vis, TEM, and Zeta potential measurements. UV-vis spectra of kinetic properties for the DNA modified gold nanoparticles reflect the high stability of the system against the addition of sodium ions. Gelatin and other solutions were also studied on the effect of stability of the gold nanoparticles.Secondly, based on the"8-17"DNAzyme, the aggregate of gold nanoparticles and DNAzyme was synthesized and whose character was determined. In the presence of Pb²⁺, the color of the aggregate turned from blue to red. Compared with Zn²⁺,Ca²⁺,Mg²⁺,Sn⁴⁺and Fe³⁺, it indicated that this DNAzyme aggregate had highly selectivity on Pb²⁺, which is fundamental to the study and application of the biosensor based on DNAzyme aggregate.Finally, the gold nanoparticles were modified by L-lysine and L-cysteine, and then the amino acid modified gold nanoparticles were dispersed in water of different pH. The color changes were observed and the properties of them were obtained through UV-vis,FT-IR,CD spectra,agarose gel electrophoresis,AFM and TEM.