The Application Of An Electrochemical Platform Based On Zeolitic Imidazolate Frameworks In The Efficient Detection Of Uric Acid

Background: Uric acid(UA),the end product of purine metabolism,is a heterocyclic compound containing nitrogen.In human body,disorder of purine metabolism can cause the increasing of UA level,leading to some serious symptoms such as hyperuricemia,gout,and arthritis.In recent years,there has been an explosive growth in the number of the hyperuricemia patients.Hospital statistics showed that,in 2020,the number of hyperuricemia patients worldwide was 0.93 billion,and would be expected to reach 1.03 billion in 2022.In our country,the number of patients was 0.17 billion in 2020 and was going to reach 180 million in 2022,i.e.,two people in ten would be the hyperuricemia patients.Hyperuricemia is now so-called ‘the fourth high symptom’ after hypertension,hyperlipidemia,and hyperglycemia.Continuous high level of UA in the blood can greatly increase the burden of organs,which can induce more symptoms and diseases.Therefore,high-performance UA detection and monitoring in blood is significant to the good health care,early disease prevention and effective clinical diagnosis.Rapid,accurate,and reliable UA measurement is of great importance for healthcare and diagnosis,even in the research of physiological and pathological process.Objective: Facile and efficient electrochemical assembling strategy was employed to grow zeolitic imidazolate frameworks(ZIFs)at carbon cloth for the building of novel electrochemical platform.The proposed ZIFs-based electrochemical platform was applied to the electrocatalytic reaction of uric acid,and a new procedure of UA detection was obtained accordingly.Finally,the newly constructed procedure was used to accomplish the rapid,accurate,and reliable UA determination in normal or hyperuricemia patient serum samples.Methods: The electrochemical assembling of sword-like nano-ZIFs modified carbon fiber at carbon cloth substrate was achieved by using the electrochemical potentiostatic method.The ZIFs modified carbon cloth electrochemical platform was characterized by field-emission scanning electron microscopy(FESEM),high-resolution transmission electron microscopy(HRTEM),elemental mapping,X-ray photoelectron spectroscopy(XPS),and X-ray diffraction(XRD)analysis.The electrochemical behavior,dynamics process,and catalytic reaction mechanism of UA reaction at the electrochemical platform were investigated by classic cyclic voltammetry(CV).Differential pulse voltammetry(DPV)was used to obtain the electrocatalytic oxidation current signal of UA,and build the efficient UA detection procedure with the using of ZIFs modified carbon cloth electrochemical platform.Results : By preparing sword-like nano-ZIFs modified carbon fiber,a novel electrochemical platform with sword-like shape and a nano-scaled size about 200 nm was synthesized.The porous structure of sword-like nano-ZIFs modified carbon fiber was revealed by HRTEM analysis results.Elemental mapping images displayed that the novel electrochemical platform of sword-like nano-ZIFs modified carbon fiber contains C,N,and Zn elements.XPS analysis further confirmed the chemical composition of the novel electrochemical platform.XRD test showed that the diffraction fingerprint peak of sword-like nano-ZIFs modified carbon fiber was consistent with that of leaf-like ZIFs reported in previous literature,which proved the successful preparation of sword-like nano-ZIFs modified carbon fiber electrochemical platform.Secondly,electrochemical method of CV was used to investigate the electrochemical behavior,electrode dynamics process,and electro-catalytic reaction mechanism of UA at sword-like nano-ZIFs modified carbon fiber electrochemical platform.Accordingly,based on the efficient electrocatalytic oxidation of UA at the newly proposed electrochemical platform,а novel UA sensor of sword-like nano-ZIFs modified carbon fiber was obtained by using DPV procedure.The CV test showed that sword-like nano-ZIFs modified carbon fiber cloth platform displayed excellent electrocatalytic effect on the oxidation of UA.The UA electrooxidation process at the new electrochemical platform was revealed as a typical adsorption-controlled dynamics process.Besides,the mechanism of UA electrooxidation at the platform electrode was concluded as a two-electron and two-proton engaged oxidation reaction.The current signal of UA oxidation was proportional to the UA concentration.DPV tests showed that high-performance UA detection could fulfilled at the proposed new electrochemical platform with the low detection limit of 5.6 nmol/L(based on the signal-to-noise ratio of 3)and the wide detection range from 0.01 to 2800 μmol/L.Besides,the proposed sensing platform also displayed a notable selectivity,repeatability,reproducibility,stability and renewability.Conclusion: By designing and constructing a novel potentiostatic electrochemical assembly strategy,the work of growing sword-like nano-ZIFs at carbon fiber was completed.The test results show that sword-like nano-ZIFs can be grown on carbon fiber,and a new electrochemical platform for uric acid detection based on sword-like nano-ZIFs modified carbon fiber is successfuly constructed.The efficient determination of UA was achieved by using the new electrochemical platform.In the UA detection of normal or hyperuricemia serum,the results of UA determination with new electrochemical platform are close to the hospital reports,indicating a rapid,accurate and reliable UA determination in human serum samples.The successful UA measurement of serum in this work could provide substantial,accurate and reliable data support for the healthcare,prevention,and diagnosis,even for the study of physiological and pathological processes.