Star-shaped Gold Nanostructures:Preparation, Characterization, And Their Application As SERS Probes In Studying Lung Cells

Surface enhanced Raman scattering (SERS) has certain application in many areas as a fast-growing spectral analysis technology, such as chemical, physical, biological, medical, public security and other aspects in social life. Optical and electrochemical properties of metal nanoparticles strongly depend on the size of the nanoparticles, morphology and the characteristics of the metal or the surrounding medium, the existence of sharp edges and branches make the nanoparticles more sensitive to the change of the local dielectric environment, this will greatly enhance the electric field intensity, so the nanometer structures with shape branches (such as gold nanostars) could be better applied in the study of SERS. In recent years, many groups haved reported the synthesis methods of gold nanoparticles with sharp branches, in this article, it firstly shows the synthesis of uniform distributed gold nanostars by the seeds mediated method, then the SERS activities of the gold nanostars are studied through experimental after modification, at the same time, a kind of SERS-based cell probe is fabricated to fulfill cell imaging and distinguish normal cells and cancer cells.The details are as follows:1. Firstly the seeds mediated method has been introduced to obtain gold nanostars with the combined action of sodium citrate and hydroquinone. Different morphology and size of gold nanostars could be controllable prepared by changing the volume of hydroquinone, HAuCl4 and gold seeds in reaction system. The optical properties and morphology of prepared gold nanostars could be characterized by ultraviolet-visible spectrophotometer and scanning electron microscope (SEM), gold nanostars with good monodispersity and morphology could be obtained.2. After preparing gold nanostars with good morphology and single uniform dispersion, Raman signal dye (NBA) and bovine serum albumin (BSA) layer would be wrapped on the surface of the gold nanostars, then the obtained SERS active tags with good biocompatibility and stability could be successfully applied in cell imaging, such as dark field imaging and fluorescence imaging.3. Finnaly a kind of antibody conjugated SERS probes would be introduced, CD44 protein will over-expressed on the membrane of some cancer cells, so as to achieve the purpose of distinguish normal cells from cancer cells. After preparing the gold nanostars, BSA would be wrapped on the surface of gold nanostars as the protective and stabilizer agent, the Raman signal dye 4MBA could be used as the bonding agent in the proess of connecting antibody to gold nanostars, finally dark field imaging and Raman imaging analysis of normal lung cells and cancer cells could be carried under the same experimental conditions. This kind of SERS probes have good application in distinguishing normal cells from cancer cells, and it is expected to be used for the early diagnosis and treatment of cancer.