Study On The Detection And Alkaline Phosphatase And NO Based On Mimic Enzyme Activity Of His@AuCNs

As a representative mediator of biochemistry,Alkaline phosphatase(ALP)actively participates in almost every aspect of biological process,ranging from metabolism,signal transduction,molecule transportation and the expression of genetical information.Structurally speaking,ALP consists of two similar monomer that contains five cysteine residues,two zinc atoms,and one magnesium atom,which gifted it with a catalytical function.As the name suggests,ALP mainly functions as a catalyzer for biological dephosphorylation and become optimally active in alkaline environments.ALP might be ubiquitously distributed,whether in prokaryotes or eukaryotes.So far,the signifificant role of ALP in modern life science is beyond doubt dispute.In research,ALP is widely used as tool enzyme for experiments related to nucleic acid edition,based on its function in removing phosphates.More importantly,in laboratory medicine,ALP is a well-established biomarker for a series of diseases.Studies have revealed that elevated ALP concentration in serum often related to biliary obstruction,osteopathy such as osteoblastic bone tumors and osteomalacia,leukemoid reaction or lymphoma Meanwhile,lowered ALP concentration might also emerge when some metabolic disorders such as Wilson's disease or hematological diseases such as aplastic anemia and chronic myelogenous leukemia happen.Of note,the spectrum of diseases linking to abnormal ALP activity remain growing.Since ALP is used so widely,precise and sensitive assays must be established to ensure the quality of ALP-linked practices.In recent years,nanomaterial-based enzyme mimics have been widely studied because of their high stability,low cost and easy preparation characteristics compared with traditional natural enzymes.Nanozymes,especially peroxidase mimics,have shown great potential in a wide range of applications.In this study,poly(N-vinyl-2-pyrrolidone(PVP)was used as a stabilizer and PDDA as a functional macromolecule to unit dispersions of cationic polyelectrolyte functionalized graphene nanosheets(GNs).The solution color with TMB and H₂O₂was found to change from colorless to blue after Hybrid assembly with GNs,studies have shown that the His@Au NCs had excellent simulated peroxidase activity after assembly.In order to improve the simulation of peroxidase activity,with different co ncentrations of GNs for assembly,the results showed that with the increase of conce ntration of GNs after assembly catalytic activity of His@Au NCs also increase,so the maximum concentration of GNs assembled His@Au NCs follow typical activity of e nzyme Michaelis Menten kinetics,compared with the single His@Au NCs showed the lowest of Km(0.032 m M)and the highest Vmax value(3.82 x 10-8 m*s^-1),it sho ws that compared with the His@Au NCs not assembled.The assembled His@Au NCs have a better affinity for TMB than other materials.Then a PPi and ALP activity detection platform was reasonably established by regulating the peroxidase-like activity of the His@Au NCs/GN.Phosphate containing metabolite(PPi)can inhibit peroxidase activity,while ALP can restore its activity by hydrolyzing this phosphorus-containing metabolite.Colorimetric switches containing phosphorus metabolites and ALP activity were realized by His@Au NCs/GN the chromogenic reaction of catalytic TMB-H₂O₂as signal generators and amplifiers.And realize the sensing of nitric oxide by using His@Au NCs/PANI/GCE sensing characteristics.Therefore,this study provides a new direction for the design and application of biosensing analysis.