Detection Of Human Biomarkers Based On SERS-enzyme Biosensor

Surface-enhancedRamanScattering?SERS?analysisisaRaman spectroscopy-based fingerprint identification method that not only provides molecular level information with strong structural features,but also has little interference from water molecules.It is also high and can be monitored in situ and in real time,making it especially suitable for the detection of biological samples.Literature studies have shown that urease is a biomarker for Helicobacter pylori.Helicobacter pylori is considered as one of the important pathogenic factors causing chronic gastritis?gastric ulcer?gastric cancer and oral disease.The incidence of gastric cancer caused by helicobacter pylori infection is also gradually increasing.Therefore,the study on the role of helicobacter pylori in the pathogenesis of gastric cancer is of great significance in preventing and treating gastric cancer and precancerous lesions.Diabetes is a metabolic disease characterized by high blood glucose,and the main component of blood glucose is glucose.Only maintaining a certain level of blood glucose can maintain the needs of various tissues and organs in the body.Therefore,monitoring the concentration of glucose is of great significance for the prevention and treatment of clinical diabetes.Thrombin is a serine proteolytic enzyme that catalyzes the conversion of fibrinogen to fibrin in vivo,which promotes blood coagulation and regulates blood coagulation.However,the blood coagulation in the body must be kept moderate,excessive blood coagulation can cause diseases such as blood clots,and severe coagulation can cause death.The concentration and activity of thrombin are important indicators for measuring the body's coagulation mechanism.Therefore,it is important to establish a rapid and ultrasensitive method for detecting thrombin.In this paper,three biomarkers?urease,glucose,thrombin?were used as research objects.According to the specific biochemical reaction,the high-sensitivity SERS substrate was designed and synthesized,and the application of SERS sensors in biomedicine was further explored,and their specific quantitative detection was realized respectively,which provided new analytical methods and techniques for clinical disease diagnosis and treatment.From the following three aspects:The characteristic response of urea at 1003 cm^-11 was monitored by portable Raman instrument.The urea content in the reaction solution was certain.When the urease concentration was relatively high and the activity was relatively large,urease could effectively decompose urea,resulting in its position at 1003 cm^-1.The SERS response is reduced;on the contrary,when the urease content is relatively low,the response of urea at 1003 cm^-11 is relatively strong,thereby establishing a correlation between urease and urea SERS characteristic peak intensity,and quantitative determination of urease is achieved.As a result,the linear range of urease was 2.35-37.5?g/mL,and the correlation coefficient R² is 0.998.The recovery of the actual sample saliva ranged from 99.9 to 101%,and the recovery rate was good.In addition,the method has high selectivity,mainly due to the specific enzyme-catalyzed reaction between urea and urease.Combining portable Raman spectroscopy,SERS analysis has excellent results The potential of urease detection in biomedical diagnostics can provide an assessment of improving individual and at-risk populations.Inspired by the versatility of the natural enzyme system,this work designed and synthesized a new type of AuNPs/Cu-TCPP?Fe?hybrid nanosheet,Ultra small gold nanoparticles grown on a two-dimensional metalloporphyrin organic Framework?MOF?nanosheet.Cu-TCPP?Fe?two-dimensional metalloporphyrin?MOF?nanosheets in hybrid nanosheets can be used as peroxygen mimetic enzymes,and AuNPs can be used as artificial glucose oxidase.Therefore,the hybrid nanosheets can be used to simulate the natural enzymes and catalyze the cascade reactions.When glucose is added,the ultra-small gold nanoparticles have the property of glucose oxidase?GOx?to catalyze glucose,generate gluconic acid,H₂O₂,and simultaneously utilize Cu-TCPP?Fe?hydrogen peroxide to mimic the properties of the enzyme.Under the action,the invisible malachite green?LMG?can be catalytically oxidized to form malachite green?MG?,and the change of MG peak intensity can be observed to realize the detection of glucose.In this work,the detection of glucose in saliva was achieved,and the minimum detection concentration was 0.16 mM.The correlation peak of the characteristic peak R² is 0.993.The recovery rate of the saliva of the actual sample is in the range of 96.9-100.8%,and the recovery rate is good.The work open up a new way for the design of nanomaterial-based multifunctional biomimetic catalysts.SERS signal was synthesized by in-situ synthesis of larger-sized gold nanoparticles,and Cu-TCPP?Fe?peroxygen was used to mimic the activity of the enzyme to further explore its practicability.In the presence of H₂O₂,AuNPs/Cu-TCPP?Fe?can catalyze the oxidation of benzoyl LMB with weaker SERS signal to form MB.Thrombin acts as a key terminal enzyme in the coagulation process in order to achieve detection of thrombin.Further modification with solublefibrinogen?Fib?does not attenuate signaling?MB?signals.When a certain amount of thrombin is added,thrombin converts soluble fibrinogen into an insoluble fibrin strand,adsorbs on the surface of the gold nanoparticle,and occupies more active sites,resulting in a weaker SERS response of the substrate Au,thereby making the signal The molecular signal?MB?is weakened.Quantitative detection of thrombin is achieved by monitoring the strength of the?MB?characteristic peak signal.This method reveals great potential for the diagnosis of coagulation-related diseases and the study of anticoagulant drugs.The results of this paper show that the combination of specific surface reactions and surface-enhanced Raman spectroscopy enables the detection of biomarkers?urease,glucose,thrombin?.The reaction sensor prepared by the method is fast,convenient and selective,and the SERS sensor based on surface reaction has great development prospect in the field of biomedicine.