Fluorescence Enhancement Of GFP Chromophore And Its Application In Cell Imaging

The green fluorescent protein (GFP) is a protein with special structure thatexhibits bright green fluorescence when exposed to light in the blue to ultravioletrange without any cofactor or substrate. GFP has attracted great attention since itsdiscovery. GFP possesses potential in maker especially in live cell or tissue due to itsstable fluorescence, simple measurement, reliable result and high stability tophotobleaching, oxidant, reductant and many other chemical reagents. Now, GFP hasbeen applied in many areas like gene expression, protein localization, biosensor,molecular biology, bioprobe and imaging.To mimic the GFP fluorescence behaviour, we first synthesized GFPchromophore by2,3-cycloaddition. One of the chromophores was acylated forpolymerization.1H and13C nuclear magnetic resonance (1H and13C NMR),high-resolution mass spectroscopy (HRMS) and Fourier transform infraredspectroscopy (FT-IR) were applied to study the structure of most intermediateproducts and all final products.Then a series of amphiphilic poly(ethylene glycol)-b-poly(methyl methacrylate)(PEG-b-PMMA) with different PMMA length were synthesized and characterized by1H and13C NMR, FT-IR and gel permeation chromatography (GPC). According tothe structure of GFP, chromophore was encapsulated in PEG-b-PMMA nanoparticles.The size and shape of nanoparticles were measured by dynamic light scattering (DLS)and transmission electron microscopy (TEM). The fluorescence enhancement of GFPchromophore was realized and applied in cell imaging. Benefiting from theappropriate size and good fluorescent property, these PEG-b-PMMA/chromophorenanoparticles were used in cell imaging successfully.