| Carcinoembryonic antigen(CEA)is one of the most widely used tumor markers in medicine and has been extensively studied in clinical analysis.The level of carcinoembryonic antigen in the serum of patients with gastrointestinal cancer is often higher than that of normal people.Therefore,the detection of carcinoembryonic antigen plays a great role to the diagnosis and postoperative monitoring of tumors.Although there are many clinically available methods for highly sensitive detection of carcinoembryonic antigens,these methods are generally problematic in that they are complicated and time consuming,technically demanding,and expensive.Therefore,the development of a simple,fast,low-cost,high detection sensitivity and accuracy of analytical methods has always been a research hotspot and difficult point in the field of bioanalysis.The development of nanotechnology has brought new opportunities to overcome many of the dilemmas facing the field of bioanalysis.This research paper aims at detecting CEA protein using the fluorescence immunoassay method,fully utilizes the high reaction kinetics of liquid biochip technology and combines the unique optical and physical properties of inorganic semiconductor fluorescent quantum dots(QDs)and noble metal nanoparticles(Au NPs),then we construct a principle of fluorescence magnetic microbeads-gold nanoparticle suspension chip detection method which based on fluorescence resonance energy transfer and the suspension chip detection method based on inorganic semiconductor quantum dots as fluorescent output signal materials.The results show that the above two methods have a good linear relationship with CEA detection,and the detection limits for CEA can reach 60 fg/mL and 10 pg/mL,respectively.The specific research contents are as follows:1.The polymer magnetic microspheres were used as carriers to obtain fluorescent magnetic microspheres by electrostatic adsorption and chemical reaction,then the microspheres were used as energy donors and Au NPs were used as energy acceptors.Thus develops a simple and efficient fluorescence resonance energy transfer(FRET)system for detecting CEA antigens.The fluorescent magnetic microspheres and Au NPs are respectively connected to a piece of DNA and connected by a CEA aptamer to form a FRET system,then the fluorescence is turned off.When the CEA antigen is added,the CEA aptamer is isomerized by the CEA antigen with high affinity and specificity and that leads to capture the CEA antigen,thereby breaking the FRET system and the fluorescence is turned on.The FRET probe constructed by this method has a good linear relationship in the range of 1 pg/mL?10 ng/mL,the detection limit was 60 fg/mL.The application of fluorescent magnetic microspheres also provides a new idea and new material for the application of bioanalysis2.Using polymer magnetic microspheres as carrier,streptavidin modified QDs(SA@QDs)as fluorescent label,flow cytometry as a means of fluorescence signal collection and analysis by suspension array technology A fluorescent immunoassay method was constructed to detect CEA.The biotinylated CEA detection antibody is obtained by activating the polymer magnetic microspheres functionalized with a carboxyl group(-COOH),then linking to a capture antibody of CEA,after that,modifying the detection antibody of CEA with biotin.Finally,coupling the detection antibody to QDs.When the CEA antigen is added,the capture antibody and the detection antibody simultaneously capture the same antigen,thereby combining the magnetic microspheres with QDs to generate a fluorescent signal and collecting the fluorescent signal by flow cytometry.The detected CEA antigen has a linear relationship within the range of 10 pg/mL?10 ?g/mL,and this method also has a good selectivity,which provides a new idea for subsequent actual samples and clinical applications. |
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