Ultrasensitive Electrochemical Aptasensor Based on Surface‐Initiated Enzymatic Polymerization

摘要: Coupled with the ability of fast and quantitative response, electrochemical aptasensors (EA) have great potential in application early diagnosis cancer biomarker. In order to determine rare biomarkers complicate clinical samples, scientists are making unremitting efforts towards improving sensitivity selectivity EA. Herein, a "sandwich"-structure aptasensor (SEA) is developed for analysis biomarker carcino-embryonic antigen (CEA). Two DNA aptamers employed, one which thiolated at 3′-terminal immobilized onto gold electrode as capture probe, while other served signal probe. The two could "sandwich" target probe then subjected terminal deoxynucleotidyl transferase (TdT)-catalyzed incorporation biotin labeled dNTPs into its 3′-terminal. Thus as-generated long oligo tails allow specific binding numerous avidin modified horseradish peroxidase (Av-HRP), resulting enhanced catalyzed signals. This amplification strategy termed surface initiated enzymatic polymerization (SIEP). SIEP amplified SEA has detection limit 10 pg·mL−1, indicating outstanding efficiency.