The Preparation And Property Study Of Intracellular Fluorescent And Magnetic Markers

In recent yeas, because of its stabillity, facility prepareation, and being prone to combine various molecules to function its surface, and because of its superparamagnetic and being convenient to separate, collect and purify sample, nanoparticles have been wildly applied to many field in biochemistry, molecular biology and clinical medicine as marker of the new generation such as magnetic separation, cell marking , medicine transmit , immune detecting and contrast agent of magnetic resonance imaging (MRI). Among them, cell markers applied in cell marking are based on contrast agent of MRI in fact, because magnetic resonance imaging has become a potential study of cell in vivo image. We observe dynamic migration stem cell and other cells by MRI. Superparamagnetic iron oxide enters the cell under the function of dye agent transferred, and then we could observe where cell goes in vivo.SPION (superparamagnetic iron oxide nanoparticles) are well established as magnetic resonance(MR) reporters for detecting pathologies in the liver, spleen and lymph nodes where, after phagocytosis, their presence is evident primarily by a darkening effect on T2 weighted images .After injection, magnetic nanoparticles accumulate in target tissues and are degraded over a period of several days, providing a convenient interval to determine nanoparticle disposition, MRI is now capable of providing high spatial resolution images of nanoparticles disposition in vitro, in small animals, and in human.In cell marking, the markers should provide not only the basis for a new class of so-called smart nanoparticles, capable of pinpointing their position through their magnetic properties, but also the information on their environment by optical imaging techniques. Here we made the best of HIV-1 Tat in strong penetrability: It could lead peptide, protein and DNA which is linked in cell with high efficiency depending on concentration, while regular structure and function of cells are not affected.In this communication, we adopted chemical reaction to prepare magnetic and fluorescent markers in which HIV-1 Tat (Trans-activating transcriptional activator) PTD (protain transduction domain) was applied. The marker could smoothly enter the cells. They may be applied to MRI because of the superparamagnetism and optical imaging in vivo because of the luminescence. The experiment take magnetic resonance contrast agent-----superparamagnetic iron oxide nanoparticles (SPION) as the core, amino groups conjugated to its surface continually, and then conjugate to Tat protein through crosslinking intermediary. In above experiments, the testing of each step is all necessary. We confirmed these experimental processes by some physics and chemistry tests, so the last samples are allowed to apply in biomedicine as biomarkers.