Dual-signal Portable Electrochemical Sensor For Detection Of Hepatocellular Carcinoma Marker GPC3

Glypican-3（GPC3）is an important serological marker for hepatocellular carcinoma（HCC）in recent years.Dual-signal electrochemical aptasensors have been widely used in the analysis of tumor markers due to their advantages of high sensitivity,strong specificity,fast response speed,low cost,higher stability and accuracy.In this paper,two dual-signal electrochemical sensors with different strategies were constructed to detect the content of GPC3 in human serum by combining the characteristics of GPC3 aptamer and nanomaterial.Based on this,a portable GPC3 electrochemical biosensor based on field programmable gate array（FPGA）was designed to achieve low-cost,convenient and high accuracy detection of GPC3.The main contents are as follows:（1）Two electrochemically active nanoprobes,Reduction of graphene oxide-Cuprous oxide nanomaterials（RGO-Cu₂O NPs）and Molybdenum disulfide@ferrocene nanomaterials（Mo S₂@Fc）,were designed and synthesized.Transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,UV-vis absorption spectroscopy（UV-VIS）,X-ray diffrotometry（XRD）and X-ray photoelectron spectroscopy（XPS）were used to characterize the two nanoprobes.At the same time,the color system of TMB and H₂O₂ was used to verify that RGO-Cu₂O NPs has good peroxidase like properties.（2）A dual-signal mode electrochemical adapter sensor based on RGO-Cu₂O NPs was constructed.The signal peak changes of Cu₂O and H₂O₂ were detected by differential pulse voltammetry（DPV）and Ampere law（i-t）respectively,and the highly sensitive detection of GPC3 was achieved.In the range of 0.1-500.0 ng/m L,DPV signal variation has a good linear relationship with the logarithm of GPC3 concentration,and its equation isΔI（μA）=4.959+1.541 lg C（R²=0.9963）,The LOD was 0.064 ng/m L（S/N=3）.In the range of 0.1-50.0 ng/m L,the linear equation of i-t signal change and logarithm of GPC3 concentration isΔI（μA）=11.3185+9.8777 lg C（R²=0.9964）,and LOD is 0.0177 ng/m L（S/N=3）.The dual-signal sensor has good stability,repeatability and specificity.In the analysis of actual human serum samples,the recoveries were 98.74%-115.51%,and the relative standard deviations（RSD）were 1.49%-5.83%.Therefore,the dual-signal sensor has potential clinical application value.（3）A dual-signal ratio electrochemical adapter sensor was designed.The reference signal Cu₂O(I_Cu)and detection signal Mo S₂@Fc(I_Fc)were recorded by DPV method,and the ratio of reference signal to detection signal(I_Fc/I_Cu)was analyzed to achieve a highly accurate and sensitive detection of GPC3.When the concentration of GPC3 was between0.01 ng/m L and 1.00 ng/m L,the linear regression equation was I_Fc/I_Cu=1.7832-0.0155*C_GPC3（R²=0.9922）.Between 1.00 ng/m L and 100.00 ng/m L,the linear regression equation was I_Fc/I_Cu=2.9926-1.1832*C_GPC3（R²=0.9955）,and the LOD value was as low as0.0012 ng/m L（S/N=3）.The specificity,stability and reproducibility of the dual signal ratio electrochemical adapter sensor for GPC3 detection were verified.The serum samples of six groups of patients were analyzed and compared with clinical ELISA.The relative error rate was 0.3%-5.29%,and the RSD was 1.34%-4.18%,indicating that the developed dual signal electrochemical adapter sensor has good reliability and accuracy.（4）A portable GPC3 electrochemical sensor was initially constructed.The sensor uses DPV in electrochemical analysis as the detection principle,RGO-Cu₂O nanomaterials modified screen printed carbon electrode（SPE）as the working electrode of the three electrodes,and field programmable gate array（FPGA）as the main control.Voltage waveform satisfying the detection of DPV is applied on the reference electrode and the working electrode by potentiostatic circuit.Through current/voltage conversion,amplification,AD acquisition and LCD display,the low cost and portable detection of GPC3 is realized.