Modified Gold Nanoparticles And Polyanilne/gold Composites

Polyaniline have attracted considerable attention for a variety of potential properties,such as high conductance, high stabilities, etc. The polymer materies have been applicated in anticorrosion coatings, electromagnetic shielding, rechargeable polymeric batteries, polymer photovoltaics. Polyaniline have lots of properties, but it`s internal infusibility limit it`s application in many fields,especially in biology. Polyaniline could be prepared by chemical oxidation and electrochemical oxidation. Introducing the metal nanoparticles, such as Au, Ag, Pt, Pd, Cu,etc. have more advantages. Generally, polyaniline-metal composite could be synthesized by original composite.Over the past few decades, the synthesis of core–shell structures has attracted a great deal of research attention. A lot of methods are applied in synthesized PANI/Au composites, but these methods can not be used in prepare the modified gold nanoparticles which could be dispersed stably in liquid. Infusibility is one of an internal property of polyniline,reducing the size of the polyaniline is the only method to change it`s infusibility without any stabilities.In this work,we report two methods to synthesize PANI/Au composite. The first, we adopted aniline as the reducing agent reduced HAuCl4 to synthesize the PANI/Au composite.Aniline have obvious reduce abilities and it could be used in making the gold nanopartiles stable. On the other hand, aniline could reduce HAuCl4 to Au directly, which is coated at the surface of the gold nanoparticles and it could be dispersed in liquid. The second, the PANi/Au is prepared by sodium citrate. we synthesized folium polyaniline at the surface of the gold nanoparticles, which is polyniline modified gold nanoparticles. (PAn@AuNPs). This method not only conquer the disadvantages of the infusibility, but also increase the stabilities of the gold nanoparticles. PAn@AuNPs could be used in biology fields hopefully.Gold nanopartilces have many special properties such as quantum size effects, suface effects, Optical effects and compatibility effects. With these properties, gold nanoparticles and their bioconjugates were widely used in clinical diagnostics and material field. At present, characterization of gold nanoparticles and their DNA conjugates are being relied on TEM and other techniques. But the equipments and operations are so expensive and complicated that economical and simple methods need to be developed. In this study, spectrofluorimeter and Gel electrophoresis were established for the separation of gold nanoparticles and modified gold nanoparticles.It is already found that gold nanoparticles could be separated under gel electrophoresis. Gel electrophoresis has electrostatic effects and molecule sieving effects so it's could split Au nanoparticles with different sizes precisely. Under these conditions, small particles have large electrophoresis mobility. Moreover it was found that the modified gold nanoparticles'electrophoresis mobility is differing from the unmodified. Small particles are determined to be optimal size for the surface modification and it could maximally increases the sensitivity of the DNA detection. Further experiments need to be developed to get better results.