A Nonfouling Electrochemical Biosensor for Protein\nAnalysis in Complex Body Fluids Based on Multifunctional Peptide Conjugated\nwith PEGlyated Phospholipid

Developing\nantifouling biosensors capable of performing robustly\nin complex human body fluids is crucial for biomarker diagnosis and\nhealth monitoring. Herein, an antifouling and highly sensitive and\nstable biosensor was constructed through the self-assembly of the\ndesigned conjugates composed of a multifunctional peptide (MP) and\nPEGylated distearoylphosphatidylethanolamine (DSPE-PEG). The self-assembly\ncapability of the DSPE-PEG-MP was demonstrated clearly through coarse-grained\nmolecular dynamics simulation and transmission electron microscopy,\nand it can be effectively self-assembled onto the electrode surface\nmodified with gold nanoparticles. The MP was designed to be antifouling\nand contained a peptide sequence that can specifically bind the target\nprotein Annexin A1 (ANXA1), and the D-type amino acid composition\nof MP can enhance its resistance to enzymatic hydrolysis. The unique\ndesign of MP, in conjugation with the self-assembly capability of\nthe PEGylated phospholipid DSPE-PEG, enabled the biosensor to exhibit\nexcellent antifouling capability and stability in various complex\nhuman body fluids. The biosensor was capable of sensitively and selectively\nquantifying ANXA1 and achieved a limit of detection down to 0.12 pg\nmL<sup>–1</sup>. More importantly, the biosensor demonstrated\nsatisfactory accuracy for ANXA1 detection in clinical serum samples,\nas verified by the enzyme linked immunosorbent assay (ELISA) kits.\nIt is expected that various antifouling biosensors suitable for application\nin complex biological environments can be constructed by utilizing\nthe strategy of designing similar DSPE-PEG-MP conjugates.