Construction And Biochemical Analysis Applications Of Fluorescent Nanoprobes

Recently, the research of fluorescent nanoprobes has been paid more and more attention of the scholars all over the world, and has been widely used in biochemical analysis, such as cell imaging, detection of biological molecules, toxic or harmful substances in the environment. This method is simple, rapid, and with high sensitivity. This paper construct multifunctional fluorescent probes with two kinds of different and novel methods. These multifunctional fluorescent probes were used for real-time fluorescence tracking of gene delivery and the sensitive and selective detection of nitroaromatics, respectively.The main research work and results are as follows:Firstly, fluorescence imaging of transduced cells and tissues is valuable in the development of gene vectors and the evaluation of gene therapy efficacy. We report here the simple and rational design of multifunctional nanocomposites (NCs) for simultaneous gene delivery and fluorescence tracking based on ZnS:Mn2+ quantum dots (QDs) and positively charged polymer coating. The positively charged imidazole in the as-synthesized amphiphilic copolymer can be used for gene loading via electrostatic interaction. While the introduced poly(ethylene glycol) (PEG) can be used to reduce the binding of plasma proteins to nanovectors, and minimize clearance by the reticuloendothelial system after intravenous administration. Most importantly, these multifunctional nanovectors showed much lower cellular toxicity than the commercial PEI transfection vectors. Based on the red fluorescence of QDs, we can real-time track the gene delivery in cells, and the transfection efficacy of pDNA encoding enhanced green fluorescence protein (pEGFP) was monitored via the green fluorescence of the GFP expressed by the pDNA delivered into the nuclei. Fluorescence imaging analysis confirmed that the QDs-based nanovectors delivered pDNA into HepG2 cells efficiently. These new insights and capabilities pave a new way toward nanocomposite engineering for fluorescence imaging tracking of gene therapy.Secondly, with the increasing needs for homeland security, human health and green environments, the detection of explosives residues and explosive-like compounds has attracted scientific concern and become an important international issue in countering terrorist threats and contamination of soil and groundwater. we developed an efficient one-pot strategy for the preparation of hydrophilic amine-functionalized nanocomposites by using hydrophobic fluorescence quantum dots ZnS:Mn2+@allyl mercaptan (QDs@AM) as building blocks through novel light-induced in-situ polymerization. The average size of as-prepared hydrophilic nanocomposites was ～50 nm, which could be further tuned by varying the concentrations of the monomers. Importantly, these nanocomposites were further utilized for the facile, highly sensitive and selective detection of nitroaromatics. The linear ranges for 2,4,6-trinitrotoluene (TNT) in 0.01-0.5 μg/mL and limt of detection the lowest detection line (LOD) is 2.2 nM,2,4,6-trinitrophenol (TNP) lie in 0.05-8.0μg/mL and LOD is 3.4 nM, respectively with barely interfered by other nitroaromatics such as 2,4-dinitrotoluene (DNT) and nitrobenzene (NB). Moreover, the novel surface modification method developed here offered a general strategy for fabricating hydrophobic nanocomposites with hydrophilic properties and indicated various potential applications including sensing and imaging.