A Novel Nano-biosensor Based On Aptamer Fluorescent Research For Proteins

Proteins are the fundamental components and they are also the important parts that life science studies. Proteins are involved in every life process and life activities, and it also relate to nutrition, structure of cells, enzyme, hormone, virus, immunity, substance transformation, heredity, origin of life and evolution et. al. They are the most components in the cells. Enzyme, hormone, antibody, transportation molecule, even the framework of cells themselves are composed by proteins. The weight of proteins is over 45%-50% of the life weights that do not include the component of water. They play important roles in all kinds of life functions. Therefore, protein analyzing is always an important subject in life science. Quantities analyzing proteins is the fundamental parts of studying proteins and it is also very meaning to study nutrition of human , diagnose diseases and analyze drugs and food.Currently, the ways used frequently have all kinds of faults. For example, turbidimetric Assay and Kjeldahl method are not very exact. Absorption spectrometry just can get low sensitivity. Light scattering assay is interfered by many factors. And the chromatogram assays influenced the activity of proteins a lot. Therefore, efforts were made for the exact, sensitive, stable assays that can keep proteins alive. In this paper, proteins were studied by the biosensors that were made of magnetic nanoparticles based on aptamers. Aptamers were used as molecule device. The affinity between aptamers and target proteins was as strong as that between antigen and antibody. That made this assay own excellent specificity and sensitivity. The nanoparticles used in this work not only can separate and concentrate the target proteins, but also can eliminate the nonspecific absorption influence of existing non-target proteins. It was helpful to reduce the fluorescence background, improve the ratio fluorescence signal to background and make the assay obtain high sensitivity. As the surface of magnetic particles were modified by carbon chain, it was easy for the biosensors to detect dual proteins in the solution. The results of experiments were satisfying.