Nanocomposite Electrochemical Sensor Used For Point Of Care Testing Of Biomolecules

With the development of economy,social progress and the improvement of the overall quality of the population,the number of people who value individual health information continues to rise.Therefore,the early warning and diagnosis of the disease is particularly important.Electrochemical biosensors play an important role in clinical immediate detection.Because electrochemical biosensors combine electrochemical analysis methods and biosensors,they have the advantages of high sensitivity,high specificity,simple operation and low cost.Nanocomposites have a large specific surface area.The introduction of higher active sites,biocompatibility and conductivity,etc.into electrochemical biosensing can catalyze the substrate to amplify the signal and further improve the sensitivity of the sensor.Based on this,electrochemical biosensors have broad application prospects in various fields.During the master's degree,the work mainly used the excellent performance of nanocomposite materials in biosensors,combined with effective target recognition strategies and signal amplification strategies,to construct electrochemical biosensors and photoelectrochemical biosensors,which realized the effect of the neurotransmitter dopamine and cancer marker(mi RNA)detection.The main research work is as follows:(1)For the sensitive detection of dopamine for the sandwich-like electrochemical biosensor based on Pt@CeO₂ nanocomposite materials.Electrochemical modification was carried out on the electrode substrate to fix DSP and MBA.The diol and amine groups of dopamine react with the boric acid of MBA and the succinimide residues of DSP,respectively,and the target can be recognized by two molecules.The functionalized Pt@CeO₂nanocomposite material is synthesized by hydrothermal method and connected with DSP and MBA to form a signal probe and signal amplifier with excellent catalytic and redox performance.Choosing dopamine as the target,electrochemical characterization methods prove that the constructed sensor has a good linear range and low detection limit,and can achieve high-specific and sensitive detection of dopamine.(2)The laser ablation method is used to corrode titanium dioxide with a specific shape and area on the titanium sheet.Cu In S₂ nanomaterials are loaded on the surface of titanium dioxide to form a sensitized structure through layer-by-layer assembly to enhance the photoelectric conversion efficiency of the electrode.Subsequently,a specific nucleic acid sequence is fixed on the surface of the electrode.The two ends of the nucleic acid can specifically recognize let-7a and fuel DNA,respectively,and the single-stranded DNA is further loaded with DA to amplify the signal.Using the non-enzyme-assisted recycling strategy allows let-7a to be recycled,and at the same time,according to different chain displacements,the photocurrent changes are generated.Based on this,a photoelectrochemical biosensor with a sensitive response to micro RNA is constructed.