Research On TiO₂ Nanowire Modification And Immunoassay Technology

With the rapid development of modern agricultural and industrial,the problem of environmental pollution is growing serious.Because Persistent Organic Pollutants?POPs?possess the properties of chronicity,cumulative,semi-volatile and highly toxic,so there are serious harm on human health and environment.And POPs are small toxic molecules,it is not easy to preparate their antibodies.Nanomaterials have unique properties associated with its surface effects,volume effects and quantum size effects,making it a center of research interests both in fundamental science and applied research.We select Octachlorostyrene?OCS?as the target molecule by preparing the corresponding antibody for immuneanalysis.In the past many decades,TiO₂ has been widely applied in many fields such as solar cell,sensor,photocatalysis,electronic due to its excellent chemical stability,non-toxicity,good optical/electric properties,but TiO₂ is limited by its relatively large band gap of 3.0 eV for rutile and 3.2 eV for anatase phases,which absorb only UV light region.Many modifications have been made on the TiO₂nanowire arrays by a lot of researchers to improve its optical and electrical properties including modify of phase composition,pore size,thick and length tube and surface modification by doping,filling and decorating techniques.These employments have extended the scope of application.Therefore,it has become a focus for wide seriously applications in many fields such as photovoltaic cell/photoelectrochemical cell,photo-catalytic degradation of pollutants,bio-sensing and drug delivery,and so on.In this paper study,A single-dimensional Ti O₂ nanowire array with uniform distribution was prepared by hydrothermal method based on titanium sheet and then the modification of titanium dioxide nanowires using metal nanoparticles and semiconductors as shown in Chapter 3.The characteristics and photoelectric properties of TiO₂ nanowires were studied.The results show that Au nanoparticles and CdS quantum dots have been successfully modified on the surface of Ti O₂nanowire arrays by using immersion deposition technique,continuous ion layer adsorption and reaction?SILAR?and electrodeposition.In this chapter,we discuss the morphological characterization and photoelectric properties of CdS/Au/TiO₂nanowire electrode.First,the loading of Au nanoparticles and CdS quantum dots significantly increases the charge transfer characteristics of titanium dioxide and reduces the photogenerated electrons and hole recombination rates,resulting in high intensity,stable and sensitive photocurrent response.Then,through the cross-linking of anti-OCS antibodies on CdS/Au/TiO₂ nanowires,we achieved the construction of octachlorostyrene-photoelectrode-free immunosensor?Chapter 4?.The photoelectrochemical immunosensor is stable,sensitive and selective,with a detection limit of 2.24 pM and a linear range of 0.1 pM to 50?M.At the same time,we also experimented with the determination of the content of octachlorostyrene in the actual water sample by immunoassay.