Development Of Electrochemical Sensors Based On Ferrocene Derivatives For C-reactive Protein Detection

C-reactive protein?CRP?had been used as an inflammatory factor,which is highly related to infectious diseases,cardiovascular diseases,malignant tumors,autoimmune diseases,depression and other diseases.It is also an effective indicator for the early detection,diagnosis,and condition assessment of these diseases.Therefore,the determination of CRP content in human serum is of great significance.There are already many methods to detect CRP in clinical applications.Electrochemical analysis have the characteristics of real-time,fast,sensitive and easy to miniaturize.It is a very effective method for CRP detection.This thesis was based on electrostatic absorption,combining the signal amplification method of small molecule chitosan?CS?,melamine?MEL?and gold nanomaterials?Au NPs?.Based on Screen Printed Electrode?SPE?,Fc?COOH?and Fc-ECG was used as an electrochemical probe to construct sensors,and CRP was detected by DPV.Its research content was as follows:?1?Development of CS/Fc?COOH?/SPE electrochemical sensor for CRP detection:According to the reversibility of Fc?COOH?electron transfer,good chemical stability and good biological activity and lipophilicity.It was used as an electrochemical probe,then modified on the bare electrode,and then CS was added dropwise to improve the conductivity of the modified electrode,and a CS/Fc?COOH?/SPE electrochemical sensor was constructed.Through the force between the CS and CRP molecules,CRP electrochemical detection was achieved.The experiments were characterized by UV-Vis UV-Vis,FS,CV,DPV and EIS.And the current response value of different concentrations of CRP was measured by DPV method.It was found that within the concentration range of1?550?g?m L^-1,the CRP concentration had a good linear relationship with its peak current value,and its linear equation:I??A?=11.263-0.01368C(?g?m L^-1),the correlation coefficie-nt R² and the minimum detection limit were 0.99471 and 0.3 ng?m L^-1,the sensitivity was0.194?A??g^-1?m L?cm^-2,I was the current value,and C was the concentration of CRP.?2?Development of Fc-ECG/MEL/Au NPs/SPE electrochemical sensors for CRP detection:Au NPs particles were deposited on the surface of SPE by potentiostatic deposition method,MEL was modified on Au NPs/SPE as an intermediate material,MEL and Fc-ECG were combined by hydrogen bonding force to construct a dual-amplified signal sensor Fc-ECG/MEL/Au NPs/SPE for CRP detection.On the one hand,the amplification effect of nanomaterials,on the other hand,MEL was used as a carrier to assist electron transfer.The combination of the two played a synergistic role in amplifying the electrochemical signal.Here,SEM,Raman,UV-Vis,FS,CV,DPV and EIS were used for characterization.And the current response value of different concentrations of CRP was measured by DPV method.In the concentration range of 0.001?1000?g?m L^-1,there was a good linear relationship between the logarithmic value of different CRP concentrations and its peak current response,the linear equation was:I??A?=7.6468-0.784466lg C(?g?m L^-1),R² was 0.99506.The minimum detection limit and sensitivity were 0.3 ng?m L^-1 and 11.104?A??g^-1?m L?cm^-2.?3?The two electrochemical sensors constructed were used for CRP detection in serum samples.The results showed that the recovery rate of the former was between92.13%and 109.18%,RSD was less than 7.26%,while the recovery rate of the latter was98.69%and 102.43%,and the RSD was less than 6.59%.Compared with CS/Fc?COOH?/SPE,Fc-ECG/MEL/Au NPs/SPE had a wide detection range,and the detection limit was reduced by 1000 times,and the sensitivity was increased by 56 times.Therefore,the sensors Fc-ECG/MEL/Au NPs/SPE was superior to the CS/Fc?COOH?/SPE electrochemic-al sensors,but they were basically consistent in both selectivity and repeatability.