Fabrication Of Sensitive Sensors Based On Supramolecules Mediated Three Dimensional Nanostructure

As a promising compound,macrocyclic supramolecular is widely used in molecular self-assembly and host-guest interaction system due to the recognition for the specificity of different molecular group.In recent years,inorganic nanocomposite material modified with supramolecules has broaden its application in nano sensors,drug loading and recycling extraction because of it integrates physical and chemical properties of nanomaterials and molecular recognition ability of macrocyclic molecules.However,the sensor designs are most focused on colorimetric sensing method,which has a narrow detection range and low sensitivity.These disadvantages limit its application in environmental,food safety and bio-medicine,etc.Therefore,to develop a new type of high sensitivity sensing method based on inorganic nanocomposites coated by super molecular has a very important significance.In this paper,gold nanoparticles?AuNPs?coated by p-sulfonatocalix[4]arene?pSC₄?was thynthesied.In the presence of dimmer guests,the recognition of super molecule to guest molecular is used to form an orderly and controllable three nano structure.This 3D-AuNPs is used to construct two new biosensors signal amplification strategies for the sensitive detection of paraquat?PQ?and acetylcholinesterase?AChE?respectively.The details are as follow:1.Fabrication of PQ optical biosensor with pSC₄-AuNPsIn this work,a new surface plasmon resonance?SPR?sensor for the detection of PQ is fabricated according to the amplification of SPR signal which is based on three dimensional nano structure with pSC₄-AuNPs.According to the structural characteristics of pSC₄,it can be immobilized onto the gold chip via a covalent bond between Au and sulfonic acid groups to form the complex pSC₄-AuNPs.When pSC₄-AuNPs is added,PQ can be modified to gold chip via the host-guest interaction between pSC₄ and aminomethyl.When the relative stable three dimensional complex which is formed by mixing pSC₄-AuNPs and PQ at proper concentration added,the complex can be immobilized onto the gold chip by the host-guest interaction.SPR signal is greatly enhanced due to high index of refraction of three dimensional nano complex and the conjugation between local surface plasmon resonance?LSPR?and SPR on the surface of gold film.Experimental results show that the change of SPR angle is linear with the change of PQ concentration,and the detection limit is 0.22 pM.This work not only constructs a biosensor for detection of PQ,but also analyzes its sensitivity.This system may be extended to develop sensors for the detection of other small molecule.2.Fabrication of AChE electrochemistry biosensor with pSC₄-AuNPsBased on the research of the previous chapter,pSC₄-AuNPs is used to construct three dimensional nano complex for the amplification of electrochemical signal.AChE is incubated with ATCh under suitable conditions.TCh is immobilized onto the surface of the gold electrode via a covalent bond,and then TCh is specific bound to the pSC₄-AuNPs by the aminomethyl.The thionine could be attached to the gold electrode surface by host-guest recognition of pSC₄-AuNPs.Then three dimensional nano structure is formed by the repeat assembly of the pSC₄-AuNPs and thionine.The electrochemical signal is enhanced by the enrichment of the thionine.The result shows that the change of the current is linear with the concentration of AChE,and the detection limit is 2.4 pU/m L.This research constructs sensitive electrochemical biosensors for the detection of AChE,and this method for the use of thionine as the signal of the sensor have a certain degree of versatility.