Electrochemical Sensors For Prion Protein And Dihydroxybenzene Isomers

Prion protein are responsible for a group of fatal neurodegenerative diseases,which is also called Transmissible Spongiform Encephalopathies(TSEs).It has been found that TSEs are caused by the transformation of cellular prions(PrPc)into their infectious isoform-diseaseassociated prion protein(PrPSC).At the presymptomatic stage,there is only small amount of PrPsc existed.Therefore,it is crucial to develop a highly sensitive method for the detection of prion protein.On the other hand,there are three dihydroxy benzene isomers:hydroquinone(HQ),catechol(CC),and resorcinol(RC).They are widely used as fundamental chemical compounds and synthetic intermediates in many fields.Dihydroxybenzene isomers are known as environmental pollutants according to low degradability and high toxicity.It is necessary to develop a strategy for sensitive,rapid and convenient analysis of dihydroxybenzene isomers.In order to detect PrP and dihydroxybenzene isomers,we have developed two kinds of electrochemical sensors.The main works are summarized as follows:(1)Using ferrocene-derivative as the mediator,an electrochemical immunosenor has been developed for the detection of PrP.Firstly,the primary andtibody(Ab1)was immobilized on the gold(Au)electrode by the mercaptoacetic acid(TGA)self-assembled monolayer.Then,the Au electrode was incubated with bull serum albumin(BSA)to inhibit non-specific adsorption.Thus,PrP can be successfully captured by Abl.In order to introduce the mediator into the sensor,we synthesisedβ-cyclodextrin(CD)modified antibodies(CD-Ab2).CD-Abs2 are used for PrP binding and subsequent noncovalent coupling with ferrocenecarboxylic acid(Fc).In this case,amounts of Fc was labeld in the system to improve the electrochemical response.This developed electrochemical immunosenor can be used for determination of PrP with a linear range of 2.5 pM to 25pM,detection limit 1.1 pM.(2)The hollow carbon nanotubes(HCNTs)synthesized by our group was used to modify the glassy carbon(GC)electrode for the simultaneous electrochemical determination of dihydroxybenzene isomers.HCNTs can provide the sensor with high electroconductibility,excellent electron transport rate and large surface area which leads to lower detection limit of dihydroxybenzene isomers.The nafion/HCNTs/GC electrode was fabricated and used to simultaneously determine three dihydroxybenzene isomers successfully.The final detection limits of HQ,CC and RC are 0.3 μM,0.6 μM and 0.9 μM,respectively.