Interaction And Detection Application Of Praseodymium Oxide Nanorod-Single-Stranded Nucleic Acid

As one of rare earth materials,praseodymium oxide nanorod(Pr₆O₁₁ NR)have excellent optical,electrical,magnetic and catalytic properties.It are widely used in industrial exhaust gas catalytic purification,photocatalytic degradation of dyes,methane catalytic combustion reactions,solid electrolytes.fuel cells and hydrogen storage materials.But so far,its biological application has not been discovered.Therefore,in order to make up for the research vacancies in this field,we will focus on the development and expansion of praseodymium oxide nanomaterials in biological detection.The nucleic acid molecule realizes the recognition of the target by base complementary pairing and other non-covalent interactions,and qualitatively detects the target through signals such as light and electricity.Based on the interaction of Pr₆O₁₁NR with single-stranded nucleic acid molecules(carboxyfluorescein-labeled adenosine pentamer FAM-A₅ and carboxyfluorescein-labeled nucleic acid aptamer FAM-Aptamer),a method for the determination of cholesterol in serum and ochratoxin A(OTA)in wine was successfully constructed.The specific research contents are as follows:(1)By exploring the effect of Pr₆O₁₁ NR on FAM-A₅,it was found that Pr₆O₁₁ NR has excellent fluorescence quenching performance and can rapidly quench the fluorescence signal of FAM-A₅.Moreover,this fluorescence quenching effect can be suppressed in the presence of hydrogen peroxide,and the degree of fluorescence signal recovery is linearly related to the concentration of hydrogen peroxide(1-10?M)(correlation coefficient R²=0.9931).Cholesterol oxidase oxidizes cholesterol to form cholestenone and hydrogen peroxide.The concentration of hydrogen peroxide is directly related to cholesterol content.Therefore,in this study,the recovery effect of hydrogen peroxide on the FAM-A₅/Pr₆O₁₁ NR complex system was combined with the cholesterol oxidase-cholesterol system,and a cholesterol detection method with simple operation,high sensitivity and good selectivity was established.The method has a linear range of 1-12?M and a detection limit of 0.1?M.Good results were obtained in the actual detection of human blood cholesterol,and the recovery rate reached 97.6-101.3%.(2)On the basis of the first part of the study,the A₅ nucleic acid was replaced with the functional nucleic acid molecule nucleic acid aptamer.The fluorescence quenching performance of Pr₆O₁₁ NR on FAM-Aptamer was systematically investigated.It was found that Pr₆O₁₁ NR also had similar fluorescence quenching effect to FAM-Aptamer..When the target molecule OTA of the aptamer is present in the environment,the aptamer preferentially binds to the OTA,leaving the surface of the Pr₆O₁₁ NR,causing recovery of the fluorescent signal.Moreover,the recovery of the fluorescence signal has a good linear correlation with the concentration of OTA in the range of 10-50 n M(R²=0.9997),and the detection limit is as low as 2 n M.The method also obtained good results in the OTA test of wine,and the recovery rate reached 92.5-103.3%.In addition,Pr₆O₁₁ NR also has the function of oxidase,which can directly oxidize colorless 2,2'-diazide-bis-3-ethylbenzothiazoline-6-sulfonic acid(ABTS).It can produces a green oxidized ABTS product.Moreover,the addition of an aptamer can significantly increase the mimetic enzyme activity.When OTA is present,the preferential binding of the aptamer to the OTA significantly reduces the activity of the Pr₆O₁₁ NR mimetic enzyme.Therefore,by using the absorbance A₄₀₅ of oxidized ABTs at 405 nm as a signal,it can be found that A₄₀₅ and OTA exhibit a linear correlation(R²=0.9865)in the concentration range of 0.05-5?M,and the detection limit is 0.03?M.