Sandwich-type Biosensor For The Detection Of ?2, 3-sialylated Glycans Based On Fullerene-palladium-platinum Alloy And 4-mercaptophenylboronic Acid Nanoparticle Hybrids Coupled With Au-methylene Blue-mal Signal Amplification

Cancer is a common and frequent chronic disease that seriously threatens human health.In recent years,the number of cancer patients and deaths has gradually increased,with about 1.6 million new cancer patients and 1.3 million cancer deaths annually in China.It has been reported that about 80%-90%of patients with early cancer can be cured,not only improving the survival rate of patients,but also improving the quality of life,and the mortality rate is also reduced;however,patients with advanced cancer rarely survive more than 5 years after treatment.Therefore,early detection,early diagnosis and early treatment of cancer are the key factors in cancer cure.?2,3-sialylated glycans??2,3-sial-Gs?are an important?tumor biomarker for the early diagnosis of cancer.In this paper,we want to use electrochemical biosensing technology to fabricate a"sandwich"sensor to achieve specific detection of?2,3-sial-Gs in serum.With the continuous innovation of new nanomaterials,electrochemical sensors have been well applied in food monitoring,environmental safety,and medicine.The aim of this paper is to combine the advantages of functional nanomaterials and electrochemical biosensors,and to use the specific recognition between biomolecules to construct a"sandwich"electrochemical biosensor with good stability,specificity,and sensitivity for the detection of?2,3-sial-Gs,which lays the foundation for the early diagnosis of cancer in the clinic.The main research contents are as follows:In this work,a neoteric sandwich-type biosensor was developed for detecting?2,3-sial-Gs using 4-mercaptophenylboronic acid?4-MPBA?to construct a novel molecular recognition system by the coordination of a boron atom of 4-MPBA to the amide group of Neu5Ac in the?2,3-sial-Gs structure.Amino-functionalized fullerene coupled with palladium-platinum bimetallic alloy nanocrystals(n-C₆₀-PdPt)was synthesized to modify the surface of a glassy carbon electrode?GCE?because the n-C₆₀ nanomaterial affords a large surface area for the on-site reduction of bimetallic alloy nanoparticles and an excellent capacity for electron transfer.Abundant4-MPBA were immobilized on the n-C₆₀-PdPt,since the 4-MPBA has the mercapto group can combine with PdPt alloy through strong adsorption.Maackia amurensis lectin?MAL?was covalently immobilized on Au-poly?methylene blue??Au-PMB?acting as the signal amplification components,which was used to recognize the?2,3-sial-Gs specifically like a second antibody linked on Au-PMB.The differential pulse voltammetry?DPV?current response of the biosensor in 5 mL of PBS?0.1 M,pH=7.4?was recorded,and the proposed sandwich-type biosensor showed a wide linear range of 10 fg mL^-1-100 ng mL^-1 as well as,a low detection limit of 3 fg mL^-1?S/N=3?.Furthermore,the proposed method exhibited good recovery and stability,indicating its potential for use in clinical studies.