The Applications In Biological Recognition And Research On The Self-Assembly Behavior Of Surfactant Functionalized Gold Nanorods

Gold nanorod is a kind of gold nanoparticle with special structure, it has unique local surface plasmon resonance properties. In recent years, the most common method for growing gold nanorods is the seed-mediated growth method, in which cationic surfactant cetyltrimethyl ammonium bromide (CTAB) as the template agent and protective agent. However, CTAB functionalized gold nanorods have biological toxicity, poor stability and poor selectivity in biomolecular detection, and it is difficult to apply in the study of biological systems or actual clinical detection. Therefore, it is need to research the surface modification and functionalization of gold nanorods. In this paper, we used the nonionic surfactant and anionic surfactant to chang the surface modification of gold nanorods, researched the influence on the structure, stability and other properties of gold nanorods, and respectively studied the analysis of small molecules in biological detection and the research on the self-assembly behavior of gold nanorods. The main results are as follows:(1) Study the important effect of the nonionic fluorosurfactant (FSN) on the gold nanorods in the field of biological molecule detection. FSN functionalized gold nanorods not only have high stability, salt resistance, acid and alkali resistance and biocompatibility, but also have a space steric effect in the surface of the gold nanorods. Because of the strong gold-sulfur interaction, this strategy exhibited favorable selectivity toward hydrogen sulfide over other anions and sulfur contained molecules with a LOD of 0.2?M. This system can also be used to evaluate the activity of cystathionine ?-synthase, a hydrogen sulfide production enzyme. The practicality of this colorimetric system was further validated by detecting biological hydrogen sulfide in human and mouse serum samples.(2) The interaction between anionic surfactants and cationic surfactant CTAB functionalized gold nanorods and influence on the dispersibility of gold nanorods have been studied. Due to the hydrophobic and electrostatic interactions between anionic surfactant and cationic surfactant, gold nanorods can produce different levels of aggregation and dispersion effects with different concentrations of anionic surfactant. At the same time, the increasing of mixing time also leads to the aggregation of gold nanorods. By controlling the concentration of anionic surfactant and mixing time, we can get the negatively charged gold nanorods which have good dispersion by using the anionic surfactant sodium dodecyl sulfonate (SDS). At the same time, we synthesized TPE-SDS which is a kind of anionic surfactant with special structure, and then interacted with gold nanorods by electrostatic interaction, expedited the self-assembly process of gold nanorods by reacting with cysteine and formed a new mesh assembly structure of gold nanorods.