A dual signal and label-free electrochemical aptasensor for mucin 1 was constructed based on hemin/ [email protected] nanocomposite ( [email protected] ). Hemin attached on the graphene surface not only improves the solubility of graphene and acts as an in-situ electrochemical probe but also exhibits excellent peroxidase-like properties to electrocatalyze the reduction of H 2 O 2 . PdPtNPs also show outstanding catalytic capacity to the reduction of H 2 O 2 and provide numerous binding sites for loading dDNA (mucin 1 aptamer and cDNA) to form the sensing interface. In the presence of mucin 1, due to the specific affinity between aptamer and mucin 1, double helix would be induced dissociation and the aptamer would be pulled off from the electrode. As a result, the electrochemical signals of hemin and H 2 O 2 were recovered. Based on these properties, the label-free and sensitive dual signal electrochemical biosensor for mucin 1 detection has been developed. The one is differential pulse voltammetry (DPV) signal of hemin and the other is chronoamperometry signal arisen from the catalytic reduction of H 2 O 2 . The linear ranges for mucin 1 were 8.0 pg mL −1 to 80 ng mL −1 and 0.8 pg mL −1 to 80 ng mL −1 with the limit of detection 2.5 pg mL −1 and 0.25 pg mL −1 by DPV and chronoamperometry, respectively. The recovery of mucin 1 in human blood serum samples was from 95.0% to 104.2%. The detection platform does not need signal labeling which greatly reduced the sophisticated and expensive procedures. The aptasensor provide a promising strategy for the determination of mucin 1 in clinical diagnostics.
Yan Zhou,Haitao Lü,Decheng Zhang,Keke Xu,Ni Hui,Jiasheng Wang
The cumulative harm caused by pesticide residues to environmental safety and human health is enormous, and the sensitive and selective detection pesticide in very trace amounts is currently a challenge. Herein, the biosensors for the ultrasensitive detection of acetamiprid (ACE) were proposed. The conducting polymer composite of phaseoloidin doped poly(3,4-ethyloxythiophene) (PL/PEDOT) was prepared with high surface area, excellent conductivity and stability, which was followed by the functionalization with poly(amidoamine) of the third generation (PAMAM). ACE aptamers were immobilized onto the platforms (PL/PEDOT and PAMAM/PL/PEDOT) for the development of ACE aptasensors. The concentration of ACE can be measured through both the increase of differential pulse voltammetry (DPV) signal change and the increase of the chronoamperometry (CA) signal change from the reduction of hydrogen peroxide catalyzed by PL/PEDOT. The ACE aptasensor based on PAMAM/PL/PEDOT exhibited linear ranges of 0.1 pg mL −1 -10 ng mL −1 and 0.1 fg-1.0 pg mL −1 , the detection limits as low as 0.0117 pg mL −1 and 0.0355 fg mL −1 (S/N = 3) through DPV and CA, respectively. Significantly, the response sensitivity of DNA/PAMAM/PL/PEDOT/GCE was 3.11 times higher than that of DNA/PL/PEDOT/GCE (by CA mode), proving that the PAMAM dendrimer can greatly enhance the sensing performance.
危险品化学品经营许可证（带存储）