Preparation And Application Of Fluorescence Encoded Microspheres Based Suspension Array

At present,tumor markers for gastric cancer have been developed one after another,among which CEA,glycoprotein（CA series）and other tumor markers commonly used in clinical detection are widely recognized.In light of the present condition of the gastric cancer morbidity and mortality are very tall,it is very important on the early screening for the diagnosis of gastric cancer,stomach cancer markers of single factor are unable to meet the requirements,so the stomach tumor markers with high sensitivity,high accuracy,fast conjoint analysis and improvement of related diseases diagnosis method has important research significance.Inorganic nanoparticles have special properties due to their special size effect,so they have special applications in some fields.Microspheres are ideal reaction carriers due to their controllable particle size,large specific surface area and easy modification of functional groups on the surface.Fluorescence coded microspheres are a composite microsphere formed by the combination of inorganic nanoparticles and microspheres,which can have both the characteristics of inorganic nanoparticles and microspheres.Fluorescence encoding microsphere technology has made great progress in recent years,and is widely used in the rapid detection of nucleic acid extraction,protein,carbohydrate and other components with high throughput and multi-component.Among many encoding technologies,quantum dot fluorescence encoding has been widely used because of its excellent optical properties,which makes encoding more convenient.Among many encoding methods,swelling method has become an efficient method for preparing coded microspheres because of its advantages such as simple operation,no need of expensive equipment and no need of extra temperature.In this paper,the fluorescence coding microspheres were prepared by coating quantum dots in silica microspheres,and the high-throughput,multi-component joint detection of different tumor markers of gastric cancer was realized.The main research contents of this paper are as follows:（1）Monochrome fluorescence-coding microspheres coated with red（625nm）quantum dots and two-color fluorescence-coding microspheres coated with green（525nm）and red（625nm）quantum dots were prepared by swelling method.On this basis,Si O₂-coated quantum dot coding microspheres were prepared by st?ber method.The prepared Qbead@Si O₂ has excellent fluorescence stability.（2）Aqueous phase Cd Te@Cd S quantum dots（QDs）with emission wavelength of 690nm were prepared by ice bath method for labeling secondary antibodies.（3）A highly sensitive analytical method for CEA detection based on QEB@Si O₂ coded microspheres combined with sandwich immunoassay and flow cytometry was developed.The main operating steps of the analysis include:The CEA primary antibody was conjugated on the surface of QEB@Si O₂-COOH by a carbonyl diimine reaction,and then CEA antigen was conjugated by the specific recognition reaction between antigens and antibodies,and finally CEA secondary antibody labeled with quantum dots was conjugated.The fluorescence signal was quantitatively detected by flow cytometry.（4）Based on three QEB@Si O₂ fluorescence codes,the simultaneous detection of three tumor markers of gastric cancer（CEA,CA199,CA724）was further realized by flow cytometry with good specificity.