Study On The Construction Of Electrochemiluminescence Sensor For Ultra-sensitive Detection Of Sialic Acid Glycans In Human Serum

Studies have found that sialylated variants are related to the occurrence and progression of a variety of cancers.After cancer cells undergo apoptosis,they will be released into the human blood,leading to increased levels of sialylated glycans in serum.Therefore,sensitive detection of its content is of great significance for the early clinical diagnosis of cancer.At present,only a few analytical methods can be used for detection,such as mass spectrometry,electrospray tandem mass spectrometry and so on.However,most of these methods have disadvantages such as cumbersome operation,time-consuming and labor-intensive,and complicated pre-processing.In recent years,electrochemiluminescence（ECL）sensors have been developed rapidly in the field of trace analysis due to their advantages of simplicity,convenience,speed,super sensitivity,and low background signal,and have gradually become a potential detection method.In this project,two different types of ECL sensors are designed for the detection of sialylated glycans（Sial-Gs）based on the synthesis of various nanomaterials with excellent properties,signal amplification strategies and potential resolution ECL strategies.The main content of the work is divided into the following two parts:Part 1.Study on the detection ofα-2,3-sial-Gs by a"sandwich"typeECL sensor based on HPSNs-NH2@AuNPs and AuPdPt NPsObjective:To prepare a"sandwich"type ECL sensor based on nanomaterials and signal quenching mechanism for ultra-sensitive detection ofα-2,3-sial-Gs.Method:Maackia amurensis lectin（MAL）,which can specifically recognizeα-2,3-sial-Gs,is connected to the nanomaterial HPSNs-NH2@AuNPs to form a substrate material with capture and signal amplification,and then further modified on the electrode surface Form a sensing platform.Then,3-aminophenylboronic acid（APBA）,which can non-specifically recognizeα-2,3-sial-Gs,is connected with AuPdPt NPs,a trimetallic nanomaterial,to form a signal probe with quenching effect.Based on the above strategy,a"sandwich"sensor with modified electrodes,test objects,and signal probes was constructed.When the analyteα-2,3-sial-Gs is present,the ECL signal of the system will be quenched due to the combination of the signal probe,and the degree of signal reduction will vary with the amount of the analyte,using an electrochemiluminescence instrument Monitor and record.Result:The detection range is 1 fg mL^-1-10ng mL^-1,the lowest detection limit can reach 0.5 fg mL^-1,and the recovery rate in serum is 96.65-105.00%.Conclusion:The ECL biosensor has extremely high specificity,good stability and high sensitivity,and provides a promising new method in clinical early disease diagnosis and drug guidance.Part 2.Study on the detection ofα-2,3-sial-Gs andα-2,6-sial-Gs by an ECL sensor based on the potential-resolved ECL strategy of Au@BSAMSs-luminol and new luminescent ZIFsObjective:Using the signal amplification strategy of nanomaterials and the potential-resolved strategy that different luminescent materials can generate ECL signals at different potentials,a new type of ECL sensor was constructed to detect two sialic acid glycan.Method:The Au@BSA Mss was synthesized and then connected with luminol to amplify its ECL signal which can emit an ECL at positive potential.Next,Au@BSA Mss-luminol was connected with Maackia amurensis lectin（MAL）to form the Signal probe 1,which can specifically recognizeα-2,3-sial-Gs.Synthesize a new type of luminescent material“TZZ”which can emit an ECL signal at negative potential,and then connect it with the Sambucus nigra（Elderberry）bark lectin（SNA）to form the Signal probe 2 which can specifically recognizeα-2,6-sial-Gs.Then,Fe₃O₄ magnetic microspheres（MMs）and 3-aminophenylboronic acid（APBA）were connected to form Capture probe which can non-specifically recognizeα-2,3-sial-Gs andα-2,6-sial-Gs.When the content of the analyteα-2,3-sial-Gs andα-2,6-sial-Gs changes will affect the ECL signal of the system,the degree of signal increase will vary with the amount of the corresponding analyte.Result:The sensor shows a good linear relationship when the detection range ofα-2,3-sial-Gs andα-2,6-sial-Gs is10 fg mL^-1-10 mg mL^-1,the detection limits can reach 2.1 fg mL^-1 and 3.3 fg mL^-1 respectively,and the serum recovery rates were 97.00-104.20%and98.31-106.29%,respectively.Conclusion:The prepared potential-resolved ECL biosensor has extremely high detection performance,and provides a promising new method for the diagnosis of early clinical cancer and drug guidance;and it can provide a new idea for the detection of multi-target objects in the future.