Study On Methyltransferase And Arsenate Detection Based On Cobalt/Iron Oxyhydroxide Nanozyme

In this paper,cobalt oxyhydroxide?CoOOH?nanoflakes and iron oxyhydroxide?FeOOH?nanorods with excellent peroxidase activity were synthesized by simple method,based on the two nanozyme materials,the optical and electrical sensing platforms were successfully constructed for the sensitive detection of methyltransferase?MTase?and arsenate?As?V??.The paper is mainly composed of the following parts:1.The introduction part mainly introduced the concept,development process,main types and related applications of nanozymes.Then the properties of CoOOH and FeOOH nanomaterials and their applications as nanozyme were summarized.Subsequently,the detection significance and the main detection methods of MTase and As?V?were introduced.Finally,the main research contents and research significance of this paper were described.2.A simple colorimetric assay for MTase activity was developed based on ssDNA enhances the peroxidase-like activity of CoOOH nanoflakes.This enhancement can be attributed to electrostatic attraction and aromatic stacking between the enzyme substrate 3,3',5,5'-tetramethylbenzidine?TMB?and ssDNA.Based on the specific recognition of MTase and restriction endonucleases HpaII and the peroxidase-like activity of CoOOH nanoflakes,sensitive detection of MTase can be achieved.The linear range was 0.08-50 U/mL,and the detection limit was estimated to be 0.069 U/mL.In addition,the colorimetric sensor could also be used to detect MTase in lysate of lung cancer cell?A549?.The representative anticancer drugs were used as model inhibitors to investigate the application of this method to the screening of M.SssI MTase inhibitors.The results showed that the proposed colorimetric sensing strategy not only enables sensitive detection of MTase activity,but also can be used to screen M.SssI MTase inhibitors.3.The highly sensitive strategy for quantitative detection of As?V?was developed by using iron oxyhydroxide?FeOOH?nanorods with peroxidase activity in colorimetric and electrochemical methods.The prepared FeOOH nanorods could oxidize the peroxidase substrate ABTS to a colored product in the presence of H₂O₂.While in the presence of As?V?,As?V?could be adsorbed onto FeOOH nanorods by electrostatic interaction and As-O bonding,adsorption of As?V?hinders the substrate ABTS from approaching the nanorods,thereby inhibiting the catalytic activity of FeOOH nanorods,resulting in a decrease in green oxidation products,observing the color change of the corresponding solution could realize the visual detection of As?V?,and the quantitatively detect As?V?could be achieved by recording the UV-vis absorption spectra.The colorimetric detection of As?V?had a detection limit of 0.1ppb.Based on the excellent conductivity of FeOOH nanorods,an electrochemical sensing method was developed to detect As?V?,FeOOH nanorods were modified on glassy carbon electrodes,the highly sensitive electrochemical analysis of As?V?was achieved by the adsorption of As?V?on FeOOH nanorods to inhibit the ABTS reduction current signal.As low as 12 ppt As?V?could be detected via the electrochemical method.This colorimetric and electrochemical dual-signal sensing method not only had good selectivity for As?V?,but also could be successfully applied to the quantitative detection of As?V?in environmental water samples.