In this work, target-responsive DNA hydrogel with high loading and good biocompatibility was used to construct chemiluminescent biosensor for specific detection of adenosine. Acrydite-modified adenosine aptamer (Acry-A-Apt), acrydite-modified single-strand DNA (Acry-ssDNA) and hemin aptamer (H-Apt) were used to prepared the DNA hydrogel, and the three single-strand DNA were partially complementary to each other. Thus, the DNA hydrogel only dissolved when adenosine and hemin were present simultaneously. HKUST-1 is a Cu-based MOFs with peroxidase-like activity. Au NPs were coated into cavities of HKUST-1 to obtain [email protected] , and the [email protected] had a stronger peroxidase-like activity than HKUST-1. [email protected] was coated in the DNA hydrogel. When only hemin was present, hemin bound to the H-Apt to form the G-quadruplex/hemin and the DNA hydrogel remained in the gel state. Therefore, the G-quadruplex/hemin was formed in the hydrogel and the excess hemin can be removed, avoiding background signal interference. Adenosine was then added and the preferential interaction between adenosine and adenosine aptamer resulted in complete dissolution of the DNA hydrogel. Subsequently, G-quadruplex/hemin and [email protected] were released simultaneously, enabling dual signal amplification of chemiluminescent biosensor, yielding a “signal on” readout. As a result, the biosensor could quantify adenosine from 4 × 10 −13 – 1.5 × 10 -10 mol/L with a detection limit as low as 1.04 × 10 −13 mol/L. The DNA hydrogel system provides a simple, sensitive and biocompatible method for the detection of adenosine which is useful in the field of biotechnology.
Herein, a sensitive and selective electrochemiluminescence (ECL) aptasensor was designed using [email protected] as accelerator towards the perylene derivative (PTC-Cys)/peroxydisulfate (S 2 O 8 2− ) system for kanamycin (KAN) assay. Firstly, the PTC-Cys was prepared by covalently binding l -cysteine to 3,4,9,10-perylenete-tracarboxylic acid, which was acted as the luminophore. Then [email protected] play the part of effective catalyst to accelerate the electrochemical reduction process of S 2 O 8 2− to produce more sulfate radical anions (SO 4 •- ), thus the ECL signal of the compound was noticeably raised by 2.4 times in comparison with that in which only luminophore and S 2 O 8 2− are present, achieving signal amplification of the ECL system. In the presence of KAN, aptamer was pulled down from the sensing interface, achieving a considerable enhancement of ECL intensity in S 2 O 8 2− solution. Upon the optimal condition, our proposed strategy can quantify the concentration of KAN from 1.0 × 10 −13 to 1.0 × 10 −8 M with low limit of detection of 4.2 × 10 −14 M (S/N = 3).Besides, our proposed ECL aptasensor exhibited excellent sensitivity, stability and specificity, and could be successfully applied to detect KAN in practical samples, which proved its potential to detect other antibiotics in food security.
Xian Liu,Like Chen,Yibo Gao,Jiebin Li,Junyong Sun,Tian Gan
In this context, an innovative design of a molecularly imprinted polymer (MIP) capped Au@HKUST− 1 nanocapsules−based electrode was described for highly sensitive and selective detection of isoproturon herbicide. The Au@HKUST− 1 nanocapsules were constructed by in−situ growth of nanoscaled HKUST− 1 crystals on Cu 2 O core materials and subsequent encapsulation of Au nanoparticles inside the hollow HKUST− 1 walls via galvanic replacement reaction between AuCl 4 − and Cu 2 O. After a further surface imprinting−directing polymerization process in the presence of hydrophobic Au@HKUST− 1, a high−performance electrochemical sensing platform was obtained and used for recognition and quantification of isoproturon. Under the optimal experimental conditions, a linear relationship was observed covering the linear range of 0.0010 − 45 μM with an ultra−low detection limit of 0.45 nM. In addition, the Au@HKUST− 1 @MIP modified electrode had higher sensing specificity for isoproturon in the application of water samples with recoveries in the range of 99.07 − 105.8% and a relative standard deviation of < 4%.
危险品化学品经营许可证（带存储）