Ehanced Electrochemiluminescence Based On Nanomaterials In Biotech Pharmaceutical Analysis

Electrochemiluminescence（ECL）,which combine controllability of electrochemical with high sensitivity of chemiluminescence analysis method,has many prominent advantages such as simple apparatu,reaction control,simple operation and high sensitivity.Among of numerous luminescent reagents,Ru（bpy）₃²⁺is regarded as one of the most excellent luminescent reagents due to its high chemical and photoelectric chemical stability.As a result of expensive prices of Ru（bpy）₃²⁺,more and more studies focus on the immobilization of Ru（bpy）₃²⁺to build a solid–state ECL sensor.Now,however,many ECL sensors have been reported are not ideal,they have some deficiencies such as poor stability,low sensitivity and selectivity.Therefore,it is necessary to continue working on building a more efficient,stable and sensitive ECL sensor.This paper combines the different excellent nanomaterials with the Ru（bpy）₃²⁺immobilization or high selective aptamers to improve the sensitivity and selectivity of the ECL sensor.On this basis,we designed multiple ECL sensors for medicine and biological analysis.The main contents are listed below:1.A novel electrochemiluminescence caffeine sensor based on a Tris（2,2,-bipyridyl）dichlororuthenium（Ⅱ）doped silica/Nafion film modified electrodeA novel method for determination of caffeine using electrogenerated chemiluminescence based on Ru（bpy）₃²⁺-doped silica(Ru（bpy）₃²⁺@Si O₂)/Nafion film modified electrode is presented in this paper.These Ru（bpy）₃²⁺@Si O₂nanopaticles were prepared by water-in-oil microemulsion method,then characterized by electrochemical and scanning electron microscopy technology.The single factor experiment was combined with response surface methodology to optimize the best experimental condition.Under the optimal experimental condition,it has good linearity in the concentration range from 5.0×10^-3～20μM（r²=0.9996）with the detection limit of 1.3×10^-3μM.The RSD for five times determination of 1.0μM caffeine was 3.8%.This method has been applied simplely and successfully to determine caffeine in cola with the recoveries from 93.7%～103.8%.2.A sensitive electrochemiluminescence folic acid sensor based on a 3D graphene/Cd Se Te/Ru（bpy）₃²⁺-doped silica nanocomposite modified electrodeA rapid,facile,sensitive electrochemiluminescence sensor was fabricated based on a 3D graphene/Cd Se Te/Ru（bpy）₃²⁺-doped silica nanocomposite modified electrode for the detection of folic acid（FA）.3D graphene which has the ability to enhance the intensity of electrochemiluminescence（ECL）was synthesized by a one-pot hydrothermal method.Then Cd Se Te served as amplification elements were successively labeled on the layer of 3D graphene.In addition,per Ru（bpy）₃²⁺-doped silica nanoparticle encapsulated a great deal of Ru（bpy）₃²⁺,the ECL intensity has been further greatly enhanced.Importantly,the ECL signal on the 3D graphene/Cd Se Te/Ru（bpy）₃²⁺-doped silica nanocomposite modified electrode was amplified by FA.The optimum detecting conditions were established by single-factor analysis and response surface multivariate optimization methodologies.Under the optimum conditions,the ECL intensity was well-proportional to logarithmic FA concentration range from 1.0×10^-11M to1.0×10^-6M with the detect limit as low as 3.6×10^-12M.In application to detect FA in drugs,the recoveries range from 95.0%to 97.5%,which indicates this sensor having potential application in folic acid analysis in real samples.3.A cyclic cataslysis enhanced electrochemiluminescence aptasensor based 3D graphene/photocatalysts Cu₂O-MWCNTsThis paper constructs an electrochemiluminescence（ECL）aptasensor for ultrasensitive detecting thrombin（TB）based on a synergistic effect of nanoparticles sensitization and cyclic cataslysis of Cu₂O.In brief,this aptasensor is composed with three parts:firstly,three dimensional（3D）graphene was dropped on the electrode to accelerate electron transfer.Secondly,the Cu₂O/multiwalled carbon nanotubes（MWCNTs）was synthesized and added to the surface of 3D graphene.Thirdly,the TB aptamers which marked with Ru（bpy）₃²⁺-doped silica nanoparticles(Ru（bpy）₃²⁺@Si O₂)was added.In the presence of TB,the aptamers would be fold into a G-quadruplex which cause the Ru（bpy）₃²⁺@Si O₂ get closer to the Cu₂O.As a photocatalysts,Cu₂O can be excited by the light of Ru（bpy）₃²⁺@Si O₂,and then the photogenerated holes（h⁺）can worked as electron acceptors to catalyse the ECL reaction to release more light,and the light could excite Cu₂O again.Hence,a cyclic cataslysis aptasensor can be built.Under the optimal conditions,this aptasensor for TB detection shows good sensitivity of a concentration variation from 5.0×10^-15to 5.0×10^-11M and the detection limit of1.3×10^-15M.4.A sensitive electrochemiluminescence ATP sensor based on a 3D graphenedeposit Au/MWCNTs-Au-Ru modified electrodeIn this study,a rapid,sensitive and slective electrochemiluminescence sensor was fabricated based on a 3D graphene deposit Au/MWCNTs-Au-Ru modified electrode for the detection of ATP.On the one hand,this aptasensor inherits the good conductivity of 3D grapheme and Au;on the other hand,inherits the good selectivity of ATP aptamer.Because of the stronger interaction of MWCNTs with single-stranded DNA than double-stranded DNA,in the presence of ATP,aptamers bind to ATP and leaves the surface of electrode.So,more MWCNTs marked with Ru（bpy）₃²⁺bind to the electrode,generating stronger ECL signal.Under the optimal experimental condition,this aptasensor for ATP detection shows good sensitivity of a concentration variation from 2.0×10^-13～5.0×10^-10M and the detection limit of 6.3×10^-14 M.