Study On Monitoring Of Chlorella Vulgaris Enriched In Hg²⁺ Based On Nanozyme Activity Triggered By Hg²⁺

As an efficient biocatalyst,enzymes have been widely used in medicine and industry.However,natural enzymes are easily denatured and degraded under severe conditions,and difficult to recover and recycle,as well as the high cost of preparation and purification,which greatly limits their practical applications.Therefore,many compounds or materials can reproduce certain functions of enzymes and be used in many different fields by design.Due to the serious damage to biology and the environment,heavy metal ions have received extensive attention.Therefore,the detection of heavy metal ions and the analysis and detection of heavy metal ions in biological enrichment are an urgent research task.However,the traditional heavy metal ions detection technology sometimes fails to meet the practical needs.Hence,it is of great practical significance to seek a fast and simple detection method.In addition,it has been proven that heavy metal ions can stimulate the peroxidase-like activity of precious metal nanoparticles.Therefore,this strategy enables the detection of heavy metal ions by regulating the catalytic activity of peroxidase-like activity of precious metal nanoparticles through heavy metal ions.Based on the above,this study anchored gold nanoparticles?GNPs?on?Carbon Dots?CDs,synthesized GNP@CDs nanocomposites,and their properties and the mechanism by which Hg²⁺can enhance its simulated enzyme activity were studied.The main contents and conclusions are as follows:1.Preparation of GNP@CDs and research on the mechanism that Hg²⁺can enhance its simulated enzyme activityFirst,the nanocomposites-the GNPs decorated on CDs,used lysine as carbon precursors and ligand/reductant agent of NPs,and through sequential microwave and biomineralization,were successfully synthesized by one-pot,denoted as GNP@CDs.It's found that the GNP@CDs shows almost no peroxidase-like activity and only Hg²⁺can triggered the activity of this GNP@CDs dramatically.The possible reason for the triggered peroxidase-like activity of the GNP@CDs was discussed,indicating the triggered-catalytic activity can't accelerate the decomposition of H₂O₂ to produce a lot of hydroxyl radicals?·OH?and is different with most nanozyme by reported.But the increase of Hg²⁺,the electrostatic attraction between GNP@CDs nanozyme and substrates is altered,resulting in more substrates binding to the nanozyme surfaces and higher activity.2.Use GNP@CDs to detect Hg²⁺colorimetrically and monitor the adsorption of Hg²⁺by Chlorella vulgarisBased on the previous part of the research,a sensitive and selective colorimetric sensor was fabricated for the quantitative analysis of Hg²⁺with a linear range of 7-150nM and a low detection limit of 3.7nM.Meanwhile,we constructed three different working electrodes for electrochemical detection of Hg Hg²⁺.These three electrode construction methods indicate that GNP@CDs is a promising material,which embodies the electrochemical detection ability of Hg Hg²⁺.Further,the proposed colorimetric triggered-nanozyme sensor was successfully applied to determine trace Hg²⁺in environmental and biological sample,and showed excellent accuracy.In summary:This paper successfully prepared GNP@CDs composite nanomaterials with simple steps,and studied the mechanism of Hg²⁺stimulating its simulated enzyme activity is the electron transfer mode,which is the interaction between triggering nanozyme and substrate The mechanism study provided evidence and used it to construct a Hg²⁺colorimetric sensor that can monitor the adsorption of Hg²⁺by Chlorella vulgaris,proving the application prospect of GNP@CDs in environmental monitoring and biological detection.