Preparation Of Metal Nanomaterials And Construction Of Uric Acid Sensor

In this paper,biosensors were constructed based on metal nanomaterials,and applied to analyze uric acid by colorimetry.The methods described in the paper have high sensitivity and selectivity for detecting uric acid,and have fast analysis speed,simple operation and can be effectively applied to the detection of real samples.The main contents of this paper are as follows:Chapter one:The various diseases caused by abnormal uric acid content in human body,the difference in the number of gout in different countries,the properties and classification of optical sensors,the selection of colorimetric sensor materials,and the introduction of natural enzymes and peroxidase mimetic enzymes are described.The research contents of this paper are described briefly,and the development prospect of colorimetric method in the field of analysis and detection is prospected.Chapter two:A uric acid biosensor based on triangular Au nanoplates-uricase was presented.In the presence of uricase and oxygen,uric acid was oxidized to produce H₂O₂.H₂O₂ etched the active“tips”area of the triangular Au nanoplates,eventually,it results in great increase in ultraviolet absorbance strength of triangular Au nanoplates.Under the optimized conditions,a linear relationship between the absorbance of triangular Au nanoplates and uric acid concentration ranged from 0.0027 to 0.5333?M with the detection limit of uric acid for 0.0013?M?S/N=3?.Some of the interfering substances?e.g.,histidine,glycine,valine and tryptophan?in human serum have no effect on the experiment.Serum samples could be detected directly with the sensing system and the obtained results are in agreement with the biochemistry analyzer test results with the average relative error for 3.9%.These results suggest that the proposed uric acid sensor has great potential in applications for clinical diagnosis.Chapter three:A simple,rapid,and effective colorimetric sensor for the detection of uric acid has been built,using the MoS₂ nanoflakes-catalyzed 3,3?,5,5?-tetramethylbenzidine?TMB?-H₂O₂ system.In the presence of oxygen and uricase,uric acid was oxidized specifically to produce H₂O₂.MoS₂ nanoflakes synthesized by hydrothermal reaction could catalyze the oxidation of TMB by H₂O₂,and engendering the colorimetric signal.Under the optimized conditions,a linear relationship between the absorbance and uric acid concentration in the range of 0.5-100?M?R²=0.996?with the limit of detection for 0.3?M?S/N=3?.The proposed sensor was successfully applied to the detection of uric acid in human serum with the recoveries over 94.54%.Thus,these results suggest that the uric acid sensor-based MoS₂-catalyzed TMB-H₂O₂ has great foreground for fast clinical diagnosis of gout.Chapter four:Built the Ag@Cu₂O nanocomposites-catalyzed TMB-H₂O₂ system for sensitive,rapid,and low-cost colorimetric sensing of uric acid.Firstly,Ag nanotriangles were synthesized by dynamic method,and then Cu₂O was encapsulated on the nanoflakes to synthesize Ag@Cu₂O nanocomposites.Ag@Cu₂O nanocomposites could catalyze the oxidation of TMB by H₂O₂?which is produced by enzymatic oxidation of uric acid?,and the color changes from colorless to blue can be observed directly with the naked eyes or can be detected by UV-vis spectrophotometer.The colorimetric sensor provided a linear absorbance response in the 0.5?M to 100?M uric acid concentration range with a 0.4?M detection limit?S/N=3?.The recovery of uric acid in human serum by the proposed sensor is over 95.7%.Thus,these results imply that the uric acid sensor provides an effective tool in fast clinical analysis of gout.Chapter five:A highly sensitive biosensor for the determination of uric acid based on Pt@Ag nanoflowers?Pt@Ag NFs?was constructed.H₂O₂ was formed by the reaction of uricase and uric acid and produced the hydroxyl radical?·OH?.The system was catalyzed by Pt@Ag NFs to change the color of TMB,and the morphology and chemical properties of Pt@Ag NFs were charaterized by transmission electron microscopy.The method can be applied to detection of uric acid in the actual samples with satisfactory results.The innovations in this study are:?1?The heavy metal nanomaterials with simple synthesis process were prepared easily,and the colorimetric sensors to detect uric acid content were high sensitivity and selectivity;?2?The colorimetric method with fast analysis speed and simple operation was applied to the detection of uric acid and several sensors with good performance were obtained.