Comparing The Effect Of Quantum Dot Labeling With Organic Fluorophore Labeling On Virus Activity

Fluorescence imaging is a kind of important methods in the field of life science. Fluorescein isothiocyanate(FITC) is the most widely used of fluorescein , but it was easy to be light bleaching, unable to use for markers of long-term tracking and investigation dynamics process, and the application in immune cells chemical technology easy cause nonspecific dyeing, low sensitivity, low fluorescence efficiency .It has been gradually replaced by the new fluorescent nanomaterials. As a new type of fluorescent nanomaterials, Quantum Dots (QDs) is a kind of ideal fluorescent probehad with wide excitation spectrum and continuous distribution, narrow and symmetry emission spectrum, adjustable color, high photochemical stability, long life and other superior glow features,which has attracted much attention in analytical chemistry and life sciences.Quantum dots (QDs) has attracted much attention in recent years because of its special optical properties, However, compared with organic fluorescent reagent, QDs larger volume, and contain toxic metal elements. A lot of people think that QDs labeling may affect the marker of biological activity. In addition, there were few reported studies on the influence of the toxicity of viruses that were taged by quantum dot. In general Avian influenza viruses has strict host specificity, it can well on natural host cell replication and transmission, therefore, we choose low pathogenic avian influenza virus H9N2 as the research object, human lung epithelial cells A549 as host cell model, With QDs and fluorescein isothiocyanate (FITC) taging H9N2 viruses and infecting host cell, compared the QDs and FITC marking effect on virus activity by the change of cell activity and cytokine secretion level after virus infection, and investigate whether quantum dots can be safely in fluorescent imaging. It is the important foundation for the research of virus pathogenic mechanism and prevention of viral diseases,and it provide important basis for evaluating the biological effect of quantum dots and on the behavior influence of the virus itself by quantum dot marked, as well as provide important basis that the quantum dots Whether or not is suitable for living tracer. Therefore, this article research has practical significance.This thesis mainly includes the following aspects of content:(1). We adopt human lung epithelial cells (A549) as insensitive host cell model to investigate the cell response (cell virability) to influenza virus H9N2 labeled by QDs and FITC and explore the host cell activity changes in the condition of same concentration and different time to comparing the effect of quantum dot labeling with organic fluorophore labeling on virus activity,(2). Taking the same strategy to marke H9N2 viruses,we explore the level of secretion of cytokines include IFN - gamma and the IL - 12. from lung epithelial cancer cells A549 which is infected by labeled virus;(3). Taking the same strategy to marke H9N2 viruses to explore the effects on cellular activity, we choose QDs605 and QDs525 which are two different size of quantum dots to lable H9N2 viruses.Our results confirm that QDs taging virus affect smaller to virus activity compared with FITC markers in a short time under the same incubation condition. QDs not only has stronger fluorescence properties than organic fluorescent reagent, but also the effect on virus activity is smaller, so it can be as a better fluorescence labeling reagents. Based on the fluorescent properties of QDs is more outstanding, QDs are more suitable for the tracer studies of the virus.