Research Of Fabricating Enzymatic Biosensor Based On Supramolecues Combinative Nanoparticles

In consequence of the big ring cavity and host-guest recognition,supramolecules exert a huge application potential on materials design,drug delivery,biochemical analysis and molecular assembly when inorganic nanoparticles play a more and more important role in biosensor because of it's excellent conductivity,catalytic and adsorption properties.Recently,macrocycle molecules decorated with inorganic nanoparticles have drawn particular interests in optical,electronic,thermal,and catalytic performances because of their unique integration between the physical and chemical prosperities of nanoparticles and the environmental friendly,biocompatibility,assembly and control capacity that molecular recognition brings to.These characters endow a broad usability for the supramolecules decorated inorganic nanoparticles.In this article,the author have projected two enzymatic biosensor based on superamolecules connective inorganic nanoparticles.1.The colorimetric assay of diamine oxidase activity with high sensitivity based on calixarene derivative-capped gold nanoparticlesDiamine oxidase?DAO?is an enzyme relates to medullary thyroid,lung,and granulosa cell carcinomas as well as cell mass during embryonic development;furthermore,the aberrant activity of DAO has a relationship to the formation of multiple cancer such as medullary thyroid carcinoma,lung cancer,granuler cell cancer and the embryo.What's more,DAO is considered to be a potential indicator of muscosa injury in clinic.Therefore,building a simple,fast,easy to operate and sensitive detection method for DAO is necessary.However,to date,the relative detection is rare,hence,in this work the author built a new color assay to detect the DAO based on the host-guest reaction between amine group of 1,6-hexanediamine?HMD?and calix[6] arene,in which pSC₆ holds the electron-rich cyclic cavity and the negative SO3-group when HMD was partly protonated in neutral media,as a result,HMD will aggregate pSC₆-Au NPs without DAO.In the presence of DAO,DAO prevented pSC₆-Au NPs from aggregating because DAO oxidases the amino group of HMD.Therefore,DAO was detected qualitatively and quantitatively.In addition,we also chose guanidine hydrochloride as a inhibitor to detect since it is not only the inhibitor of DAO but also plays a considerable part of treatment for diabete's therapy.The results show that DAO detection limit is 0.0621 m U L-1 and the biggest inhibition ratio is 54%,with a IC50 value is 2.4 m M.2.An electrochemical for Caspase-3 based on CB[8]@2MV connective Ag NPsCucurbit[8]uril?CB[8]?is a member of CB,it has a rigid hydrophobic cavity of low polarity,the big cavity allow it to bind two apolar-hetero/homo guests in its cavity simultaneously which may change the electrochemical behavior of both the host and the guest.Caspase-3 is a cell apoptosis protease,the abnormal expression can lead to the occurrence of various diseases,hence building a method to monitor Caspase-3 closely is of great significance to the clinical diagnosis and treatment,however,in presence,there is no method to assay the Caspase-3 that can meet the demand of clinic.Therefore,in this paper,we firstly study the electrochemical influence of the guest bring to the CB[8],then applied the CB[8]@2MV,the group that makes a strongest signal response to detect Caspase-3.In the comparative part,the author modified the FC to the gold electrode firstly,a peptide that could bind to the CB[8] specifically through host-guest reaction,then the CB[8] could incorporate the Ag NPs,and the Ag NPs could further immobilize the CB[8] or CB[8]@guest-Ag NPs to form a mesh of CB[8] or CB[8]@guest-Ag NPs on the electrode surface,make the CB[8]-Ag NPs and CB[8]@guest-Ag NPs compared come true as well as signal enhancement.As to the Caspase-3 detecting part,the author used the EC as the substrate peptide,which was block with acetyl that can't combine with CB[8] without Caspase-3.Theoretically,there is no signal without Caspase-3;when adding with Caspase-3,Caspase-3 can cut the EC specificity to FC and expose the phenylalanine,the phenylalanine can bind to CB[8] and trigger the following reaction,then produce a strong signal response,so as to achieve sensitive detection of Caspase-3.The study results show that CB[8]@2MV has the strongest influence in the system's electron transfer and the order is CB[8]@2MV> CB[8]@ANT@MV>CB[8],the Caspase-3 detection limit is 24.62 pg m L-1.