Min Chen,Yang Li,Rui Han,Qiuji Chen,Lingyun Jiang,Xiliang Luo
Herein, an electrochemical immunosensor capable of detecting targets in human serum with ultralow fouling and high sensitivity was successfully constructed through a click reaction. One designed biotinylated peptide was associated with the other peptide functionalized with biotin and azide groups at its two terminals, to form a branched antifouling peptide through the streptavidin-biotin affinity interaction, and it was attached to the electrode to construct an antifouling interface. Then, the exposed azide group on the branched peptide was used to link the antibody modified with 5′-dibenzocyclooctyne (DBCO), and the immunosensor was thus constructed with the aid of the click reaction between the azide group and the DBCO. The developed antifouling immunosensor demonstrated a wide linear response range for carcinoembryonic antigen (CEA) and a low limit of detection of 40 fg mL −1 , which is much superior to the sensing performance of the immunosensor prepared through the normal EDC/NHS method. The immunosensor was capable of assaying CEA in undiluted serum samples with satisfying accuracy when compared with a clinically approved method. This work offered an effective strategy to develop various biosensors through the conjugation of antifouling peptides with different antibodies.
Dong Han,Baolin Zhang,Chuangang Chong,Cuiping Rong,Jie Tan,Rusen Yang
Effective attachment of magnetic nanoparticles to neuronal membranes has far-reaching significance in activating ion channels and treating neurodegenerative diseases. Superparamagnetic iron oxide nanoparticles (SPIONs) synthesized by the polyol pyrolysis method have the advantages of rich surface functional groups, excellent magnetic properties, controllable particle size and water dispersibility. We propose that perfusion of biotin into the targeted brain area should be initially performed because it tends to be adsorbed by cell membranes, followed by injection of streptavidin (SA)-modified SPIONs into the same area of the brain. By means of the strong binding force between SA and biotin, the SPIONs may subsequently adhere to the cell surfaces in the brain area. In this work, fluorescein isothiocyanate-streptavidin (FITC-SA) was modified on the surface of polyethylene imine (PEI)-SPIONs by the EDC–NHS method and stereotaxically injected into the biotin-supplemented substantia nigra of mice. The combination of fluorescence detection with transmission electron microscopy (TEM) confirmed that FITC-SA/PEI-SPIONs adhered to neuronal membranes in the substantia nigra of mice 24 h after injection. The results show that our strategy can promote the attachment of SPIONs to neuronal membranes.
危险品化学品经营许可证（带存储）