Study On The Preparation Of Ag Nanomaterials And Its Application For The Detection Of Proteins By Surface-enhanced Raman Scatting

Surface-enhanced Raman spectroscopy(SERS),as a fingerprint technique,has the advantages:trace,non-destructive,rapid and fingerprint recognition.It can provide abundant information of biomolecular structure and its vibration.In this paper,solid-state SERS substrates for rapid detection of protein molecules and suspended SERS substrates for protein detection in living organisms were prepared by self-assembly method respectively.The main contents are as the following:(1)Silver nanomaterials were synthesized by different methods.The hydrothermal synthesis method of Lee&Meisel was mainly studied and improved.By controlling the time of boiling in the early stage,the spherical silver nanoparticles were successfully synthesized and both of them were characterized by TEM and UV-Vis,etc.(2)We have optimized the traditional secondary oxidation method by adding an excess of concentrated sulfuric acid and adjust the speed of adding graphite powder and potassium permanganate,etc.,to prepare a better dispersion of graphene oxide which was characterized by TEM,UV-Vis and Raman spectroscopy.(3)Introducing the good-dispersion graphene oxide as a loaded platform,we adjusted the amount of added NaCl,HC1 to open the electric double layer of graphene oxide and the surface of the silver nanoparticles.And then controlled aggregation of silver nanoparticles and adsorbed onto the graphene oxide to form substrates with high SERS effect,enabling label-free detection and analysis of trace proteins.(4)According to self-assembly technology,silver nanoparticles were adsorbed onto the glass surface caused by opposite charges attraction.By placing the glass modified by poly diallyldimethylammonium chloride in silver colloids we developed the "hot spots" on the substrates so as it had good SERS effect.And then the substrates were soaked in different acidified proteins and different concentrations of proteins to study the SERS effect.The Scanning Electron Microscope(SEM)was used to illustrate the substrates.