Electrochemical Immunosensor Based On Carbon And Gold Nanoparticles For Detection Of Two Lung Cancer Markers

Lung cancer is a malignant tumor with a high incidence and increasing mortality across world.And the lung cancer mortality is closely related to the content of specific biological markers in the body.Therefore,the qualitative and quantitative detection of lung cancer markers is of great significance for the early diagnosis and prognosis of lung cancer.Compared with traditional immune detection methods,electrochemical immunosensor has many advantages,such as fast response,safety,non-invasive,high sensitivity and simple operation.In the past few years,nanocomposites have been widely concerned and applied because of their unique physicochemical and biological properties.In this work,nanomaterial and nanomaterial nanocomposites with a series of excellent properties to were employed to construct the sensitive electrode interface and electroactive nanoprobe with high sensitivity for the detection of two model tumor markers,CYFRA21-1 and CEA.The main contents of this work carried out as follows:（1）An electrochemical immunosensor for detection of CYFRA21-1 based on3D-G@Au modified electrodeThree-dimensiona graphene@gold nanoparticles（3D-G@Au）nanocomposite was modified on the glassy carbon electrode（GCE）surface to enhance the conductivity of immunosensor.The anti-CYFRA21-1 captured and fixed on the modified GCE through the cross-linking of chitosan（CS）,glutaraldehyde（GA）and anti-CYFRA21-1.The differential pulse voltammetry（DPV）peak current change due to the specific interaction between anti-CYFRA21-1 and CYFRA21-1 on the modified electrode surface was utilized to detect CYFRA21-1.Under optimized conditions,the proposed electrochemical immunosensor exhibited a wide linear range of 0.25⁸00 ng/mL with low detection limit of 100 pg/mL（S/N=3）towards CYFRA21-1.The recovery rates of serum samples were tested to be in the range from 95.2%to 108.7%.And the developed immunosensor also shows a good correlation（less than 6.6%）with enzyme-linked immunosorbent assay（ELISA）in the detection of clinical serum samples.（2）An electrochemical immunosensor for detection of CYFRA21-1 based on3D-G,MWCNTs and AuNPsIn order to further enhance sensitivity and selectivity of the sensor system,we manufactured a sandwich-type electrochemical immunosensor based on signal amplification strategy of multiple nanocomposites to test CYFRA21-1.The proposed immunosensor fabricated by 3D-G,CS and GA composite on the GCE with a large surface area is prepared to immobilize primary antibodies（Ab₁）.To further amplify the electrochemical signal,the trace tag on the foundation of gold nanoparticles（AuNPs）is coated with amino-functionalized carbon nanotube（MWCNT-NH₂）nanocomposite through thionine linking,which enables more amino groups to capture more horseradish peroxidase-labeled antibodies（HPR-Ab₂）and subsequently enhancing the electrode conductivity.Under optimal conditions,the developed immunosensor exhibits excellent analytical performance for the determination of CYFRA21-1 with a wide linear range from 0.1 to 150 ng/mL and a low detection limit（LOD）of 43 pg/mL.Moreover,the recovery rates of serum samples were in the range fro m 91.0%to 108.9%and the developed immunosensor also shows a good correlation（less than 6.4%）with ELISA in the detection of clinical serum samples.（3）An electrochemical immunosensor for simultaneous detection of CYFRA21-1and CEA based on 3D-G/AuNPsThe simultaneous detection of two tumor markers has better clinical guiding for the analysis of lung cancer.So we manufactured an electrochemical immunosensor based on signal amplification strategy of multiple nanocomposites to simultaneously test CYFRA21-1 and CEA selectively and sensitively.3D-G was modified on the GCE,followed by deposited a layer of AuNPs.The antibody protein can be captured on the electrode to form the sensitive interface of the sensor because of a strong coordination forming between the AuNPs and-NH₂ functional group.The modification of anti-CYFRA21-1 and anti-CEA with Au-pThi and Au-pMCP can greatly enhance the electrochemical signals of Thi and MCP.Therefore,the sensitivity of detection of antigen or antibody can be improved.Under optimal conditions,the developed immunosensor exhibits excellent analytical performance for the determination of CYFRA21-1 and CEA.A linear range from 0.5 to 200 ng/mL was obtained,with low detection limits（LOD）of 0.18 ng/mL and 0.31 ng/mL for CYFRA21-1 and for CEA,respectively.Moreover,the recovery rates of serum samples in the range from 92.1%to108.4%and from 94.3%to 107.0%were acquired for CYFRA21-1 and CEA,respectively.These results indicated that the prepared electrochemical immunosensor has potential applications in clinical detection analysis.