Study On Colorimetric Detection Of Pyrophosphate Anion And Alkaline Phosphatase Based On Mimic Enzyme

Nanoenzymes are simple,stable substitutes for natural enzymes,and are widely used in biosensing,cancer treatment,environmental protection,and antibacterial treatment.currently,research on the structure and catalytic mechanism of nanoenzymes has brought the development of nanoenzyme biosensors into the focus.Among them,colorimetric sensors that are simple,inexpensive,visualized,and easy to biosensor show great application prospects.However,the catalytic activity of most nanoenzymes is much lower than that of natural enzymes.Therefore,it is very desirable to develop an effective strategy to specifically adjust the catalytic performance of nanozymes for colorimetric analysis and promote its practical application.Metal nanoclusters(NCs),as a new type of high-efficiency catalyst,exhibit high catalytic activity and selectivity in many reactions.Compared with other nanomaterial enzyme mimics,NCs are more prominent in biological analysis due to their ultra-small size,accurate molecular formula and excellent stability.Based on the above,this study effectively assembled histidine-protected gold nanoclusters(His@AuNCs)on the surface of cationic functionalized graphene oxide(PDDA/GO)to form nanocomposites(AuNCs/GO).Based on its enhanced enzyme mimic activity,a colorimetric sensor that can be used for actual sample detection is established.The main content and conclusions are as follows:1.Preparation of AuNCs/GO nanocomplexes with enhanced enzyme mimic activityThis study found that His@AuNCs has oxidase-like activity.The AuNCs/GO nanocomposite with enhanced oxidase-like activity was successfully prepared by using the gold nanoclusters and PDDA/GO electrostatic self-assembly.The nanocomposite was characterized by Transmission electron microscope(TEM)and Energy spectrum analysis(EDX),and its enzyme catalytic performance was evaluated.This study also found that Cytidine protected gold nanoclusters(Cyt@AuNCs)has a good peroxidase mimic activity,and its catalytic mechanism mainly comes from catalyzing H₂O₂to generate Hydroxyl radicals(·OH).2.Pyrophosphate anion(P₂O₇^4-,PPi)detection based on color development strategy of inhibiting AuNCs/GO enzyme mimic activityTo investigate the interaction between AuNCs/GO and PPi,a metal-free detection PPi based on inhibition of nanoenzyme catalytic activity was developed for sensitive and selective colorimetric detection at micromolar level(0–40?M).This colorimetric analysis method that inhibits the catalytic activity of nanoenzymes opens up a more direct,convenient,and greener alternative to actual PPi detection.3.Detection of alkaline phosphatase(ALP)activity based on the regulation of AuNCs/GO oxidase-like activityThe colorimetric sensor for sensitive and selective detection of ALP activity was developed according to the principle that PPi can inhibit the enzyme-like activity,ALP can specifically hydrolyze and restore the enzyme mimic activity.The linear response range of the colorimetric sensor measured ALP is 0-40 m U/mL,and the lower limit of detection(LOD)value is 0.26 m U/mL.This nanoenzyme-based colorimetric switch can be used to detect the ALP content in human serum,indicating the effectiveness and reliability of the developed colorimetric sensor applied to real samples.In summary,this paper successfully synthesized two kinds of gold clusters protected by biomolecules and discussed their enzyme mimic activities.Subsequently,AuNCs/GO nanocomposites were prepared in a green and simple way,which significantly enhanced the oxidase-like activity of His@AuNCs.By adjusting the oxidase-like activity of AuNCs/GO,the detection of PPi and ALP is realized,and a fast,sensitive and stable colorimetric sensor for detecting ALP is constructed.This colorimetric analysis method also provides a new idea for the establishment of other color reaction systems based on nanoenzymes.