Construction Of Carbon-based Nanointerfaces And Biosensing Applications

Electrochemical biosensor is a kind of sensitive element for analysis and detection formed by combining biomolecules with special recognition ability and transducers that can record electrical signals.It has been widely used in medical diagnosis,food safety,environmental protection,process control and life science discovery research.Achieving the effective mutual recognition of target molecules and bio-probe molecules is the key to the successful construction of electrochemical biosensors.Therefore,the construction of biosensing interfaces with high-efficiency recognition capabilities is crucial for the progress of sensing reactions and the acquisition of signals.Many biological nanomaterials and inorganic nanomaterials have become the preferred materials for constructing sensing interfaces due to their special structures and properties.The detection sensitivity,signal-to-noise ratio,and stability of electrochemical biosensors can be improved through effective interface construction to regulate biomolecular recognition.Therefore,in order to improve the sensing performance of electrochemical biosensors and the application research in the field of POC,we will elaborate from the following parts.(1)Carbon-based nanointerfaces constructed with DNA FNA and gene detection of SARS-Co V-2DNA tetrahedral framework nucleic acid,as a biological nanomaterial,has become the preferred material for constructing electrochemical sensing interfaces in recent years due to its unique rigid structure and stability.The surface of the carbonbased sensing interface is rough,and some areas even have defects,which seriously affect the effective recognition of nucleic acid molecules on surface,which in turn affects the detection performance of such nucleic acid biosensors.In order to make up for the above shortcomings,we constructed a DNA tetrahedral framework nucleic acid carbon-based nanointerface and studied its sensing mechanism.The entanglement on the interface improves the recognition ability of biomolecules,and can avoid the adsorption of protein molecules on the carbon-based interface,reduce the background signal,and improve the sensing signal-to-noise ratio.At the same time,combined with the signal amplification strategy of dual-signal probes,high-sensitivity detection of SARS-Co V-2 nucleic acid and effective differentiation of mutant viruses are achieved.(2)Carbon-based nanointerfaces constructed with MWCNTs for SARS-Co V-2 protein detectionCarbon nanotubes as an inorganic nano-materials is molecular-scale nanowires with excellent mechanical,chemical,electrical and biological properties,which are widely used in biosensing research.We constructed a carbon-based nano-sensing interface with MWCNTs and investigated the sensing mechanism.MWCNTs have high specific surface area and can provide more binding sites as molecular scaffolds when assembling protein molecules with recognition function.Meanwhile,MWCNTs can improve the conductivity of carbon-based interface and accelerate the electron transfer rate at the electrode interface during biosensing.High-sensitivity detection of SARSCo V-2 antigens and antibodies was achieved,and the detection sensitivity have reached f M level.After the carbon-based interface of the immunosensor was modified by MWCNTs,the sensing signal-to-noise ratio and stability were significantly improved.(3)Carbon-based nanointerfaces constructed with Au NFs and POC electrochemical immune-sensing detectionElectrochemical biosensors with carbon-based interfaces have been used in the field of POC fast detection because of their low price,easy structural design,and integration.We electrodeposited nano-gold popcorn on the carbon-based interface.This nanostructure has good electrical conductivity,high specific surface area and biocompatibility,which was conducive to the assembly and biological recognition of protein molecules on its surface,and could effectively compensate for carbon-based surface defects at the interface.Based on this,we constructed a carbon-based nanointerface modified by nano-gold flowers,combined with immunochromatography technology,and integrated an electrochemical immunochromatography sensor chip.This sensor chip has the advantages of short reaction time,low cost and strong portability.Taking the detection of prostate-specific antigen PSA as an example,it could not only distinguish healthy people from prostate cancer patients,but also complete the detection within 25 minutes.It has very high potential application value in the field of multi-scenario POCT.