Investigation On The Optical Fiber Aptamer Sensor For The Detection Of Tumor Marker CEA

Carcinoembryonic antigen(CEA)is ubiquitous in human serum.Under normal circumstances,CEA concentration is generally lower than 5ng/ml.When the concentration of CEA in human serum exceeds 20ng/ml,tumors may appear.Clinically,carcinoembryonic antigen is defined as a broad-spectrum tumor marker,which has a certain role in the detection of lung cancer,colon cancer and other tumor diseases.With the gradual development of nucleic acid aptamer technology and optical fiber sensing technology,many advantages exhibited of the optical fiber aptamer biosensor in biomedical detection and attracted people's great interest.Among them,the application of fiber-optic biosensors based on aptamers in the detection of biomolecules,especially tumor markers,has become an important research hotspot in recent years.Based on the principle of specific binding between CEA aptamer and CEA,an optical fiber aptamer biosensor for detecting carcinoembryonic antigen was designed.The sensor utilizes the localized surface plasmon resonance(LSPR)of gold nanomaterials.First,a layer of gold nanofilm is fixed on the surface of the fiber.When the CEA aptamer and CEA combine to form a complex on the surface of the gold nanomembrane,the extinction spectrum of the fiber surface will change due to the influence of the plasmon resonance effect on the surface.This change can be used to perform real-time and dynamic analysis of the CEA concentration,and through the linear relationship between peak change ?A and CEA concentration ? can achieve quantitative detection of CEAThe optical fiber was pretreated by HF corrosion coating to expose the core of the fiber and expose the evanescent field.The gold nanocolloid was prepared by a chemical reduction method and modified a layer of gold nanofilm by a silane coupling agent self-assembly film method on the fiber core surface.Designed to screen the sequence of the CEA aptamer and thiolated the selected CEA aptamer,using the gold-sulfur bond bonding force to self-assemble the aptamer onto the surface of the gold nanofilm.Then the optical fiber aptamer biosensor was successfully constructed.The solution containing CEA was detected by an optical fiber aptamer biosensor.The kinetics of the binding of carcinoembryonic antigen aptamer and carcinoembryonic antigen was observed.Two groups of protein interference experiments were set up,and the lowest detection of the sensor using the immune sandwich method.Limit research.The experimental results show that the response time of the fiber aptamer biosensor is 30 seconds,and the concentration of carcinoembryonic antigen in the range of 20 ng/ml to 200 ng/ml is linearly related to the peak of the extinction spectrum of the sensor,and the biosensor has good specificity and selection.Sex,the use of direct detection method to obtain the minimum detection limit of the sensor is 20ng/ml,while the sandwich method for detection,the minimum detection limit to 5ng/ml.