Author : Siyu Tu
Publisher :
ISBN 13 :
Total Pages : 107 pages
Book Rating : 4.:/5 (114 download)
Book Synopsis Fluorescent Gold-silver Alloy Core Silica Shell Nanoparticles for Bioimaging Applications by : Siyu Tu
Download or read book Fluorescent Gold-silver Alloy Core Silica Shell Nanoparticles for Bioimaging Applications written by Siyu Tu and published by . This book was released on 2016 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials have been a popular research field for decades and scientists are always trying to develop novel materials. This can be achieved with a hybrid of existing material to either significantly improve the performance for certain applications or generate new properties which can be exploited for new applications. Two perfect examples are gold-silver (Au/Ag) alloy nanoparticles (NPs) with strong and tunable extinction spectra in the visible range and superluminescent NPs with a metallic core and dye-doped silica shell. Both of them can be used as contrast agents for biomedical imaging applications. This research is based on the combination of these two types of NPs: the demonstration of a multiplexed bioimaging application with fluorescent NPs composed of a Au/Ag alloy core and a fluorophore-doped silica shell(Au/Ag SiO2). It has long been known that immunofluorescence, as the standard technique to label cells, has some drawbacks such as intensity limit, limited multiplexing and loss of signal due to photobleaching. Plasmonic NPs do not photobleach and do not lose their scattering signal. The Au/Ag alloy NPs with a core-shell structure not only exploit the merits of a tunable scattering signal from the core but also the metal enhanced fluorescence (MEF) effect from the shell near a metallic surface. In this research, we have fabricated the hybrid NPs and applied them in a multimodal platform to detect both scattering and fluorescence signals in order to improve the multiplexing capability. During the master study, Au/Ag SiO2 NPs were successfully fabricated with high reproducibility. Different fluorophores with different emission wavelengths were incorporated in the silica shell of Au/Ag SiO2 NPs resulting in a stronger fluorescence signal in the presence of a metallic core. An etching effect of the metallic core was noted during the silica shell growth, creating a spacer between the surface of the metallic core and silica shell resulting in a slight blueshift of the plasmonic peak. This effect is more severe for silver-rich cores. Four types of NPs were prepared, with two different Au/Ag composition ratios (pure Ag and 50/50 Au/Ag) and two different fluorophores (fluorescein and rhodamine B) were incorporated into the silica shell for a bimodal multiplexed imaging test in scattering and fluorescence. A proportion of 86% of NPs on a glass slide can be identified and a similar result was obtained for NPs on cells.