Lin Zhang,Chengfang Qiao,Xiangyang Cai,Zhengqiang Xia,Jing Han,Qi Yang,Chunsheng Zhou,Sanping Chen,Shengli Gao
Optimizing the microenvironment of MOF pore is an effective strategy to improve the sensitivity of MOF-based electrochemical biosensors. In this work, a series of isomorphic 3D chiral Ni-MOFs with different pore sizes were prepared and used to construct acetylcholinesterase (AChE) biosensors for the electrochemical detection of chiral drug inhibitor galantamine hydrobromide (GH). The combination of the dense metal nodes with intrinsic oxidase-like activity and the high active AChE, creates synergistic catalysis hydrolysis of acetylthiocholine chloride (ATCl) to produce fast sensing response. The more matched size and chirality of MOF pore significantly enhance the host–guest interactions between the substrate and biosensor, which allows the optimum AChE/ L-Ni-BPY /DpAu/GCE platform to exhibit highly sensitive detection of GH, with a lowest detection limit of 0.31 pM and a wide linear range of 1 × 10 −12 ~ 1 × 10 −6 M among the reported pharmaceutical AChE inhibitor sensing systems. Such matching effect is identified and quantified with accurate apparent energy through the detailed microcalorimetry investigations, which well illustrates the structure–activity relationship of the as-synthesized biosensors. The thermodynamically-guided assembling strategy provides new insights into the development of practical MOF-based electrochemical sensors.
Liu Wenjuan,Yao Jun,Cai Minmin,Chai Hankuai,Zhang Chi,Sun Jingjing,Chandankere Radhika,Masakorala Kanaji
A new nanopesticide, carboxymethyl-β-cyclodextrin-Fe 3 O 4 magnetic nanoparticles-Diuron (CM-β-CD-MNPs-Diuron), was synthesized from an inclusion complex of CM-β-CD-MNPs as host and diuron as guest molecules. The transmission electron microscopy revealed it had an average diameter of 25 nm which is more or less the same as that of MNPs (average diameter ~23 nm). The CM-β-CD grafting was confirmed by infrared spectroscopy, and the amount of CM-β-CD grafted on the surface of MNPs was determined to be 144.1 mg/g by thermogravimetry. The feasibility of using CM-β-CD-MNPs as a nanocarrier for loading diuron was verified by investigating the formation of inclusion complex. The complexation of CM-β-CD-MNPs with diuron followed the Langmuir adsorption isotherm. In this work, the potential toxic effect of CM-β-CD-MNPs-Diuron on soil microbial was evaluated by microcalorimetry, urease enzyme and real-time quantitative PCR (qPCR). The thermokinetic parameters were observed to decrease with increase in the loading of CM-β-CD-MNPs-Diuron in soil. The urease activity data showed that there was a significant effect ( p < 0.05) of CM-β-CD-MNPs-Diuron on the enzyme activity. The microcalorimetric analysis was in agreement with qPCR, confirming the toxic effect of this nanopesticide on microorganism in soil.
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