Synthesis, Characterization And Application Of Rare Earth Nanomaterials In Biosensors

Electrochemical biosensor is a novel derivative technique containing multidiscipline.In recent years,relying on the characteristics of its high sensitivity,quick test and good selectivity,it has been developed rapidly and used widely in the fields of clinical medicine,food testing and environmential monitoring and so on.Rare earth owns varieties of unique physical and chemical properties due to 4f electronic shell,and it can effectively improve the performance for biosensor;Nanomaterials own good biocompatibility and can enhance the stability and electrotransfer rate while being applied onto the biosensor.In this paper,hydrothermal synthesis method was used to synthesize series of nano-rare earth compound,meanwhile,the structure and size were characterized,according to unique physical and chemical properties both of rare earth and nanomaterial,and it was introduced to biological sensing as sensing medium to prepare a novel nano-rare earth biosensor in order to improve the performance of biosensor.The main research results are described as follows:?1?Glucose biosensor based on rare earth molybdate Dy2?Mo O₄?3-Au NPs composite nanomaterial Nanometer material of dysprosium molybdate?Dy2?Mo O₄?3?was employed for the fabrication of glucose biosensor by immobilizing glucose oxidase?GOD?on the Au NPs-Dy2?Mo O₄?3 composite nanomaterial.Dy2?Mo O₄?3 and Au NPs-Dy2?Mo O₄?3 were first synthesized and characterized by transmission electron microscope?TEM?,energy-dispersive spectrometry?EDS?and UV-vis absorption.The electrochemical behavior of the biosensor was full studied.The experimental results indicated that Au NPs-Dy2?Mo O₄?3 nanocomposite material presented good biocompatibility for GOD and could accelerate direct transfer rate between the immobilized GOD and the electrode.The biosensor showed a good linear relationship in the concentration range of glucose from 0.01 to 1.0 mmol×L-1 and the lowest detection limit?S/N=3?was 3.33 ?mol×L-1.Additionally,the biosensor owned satisfied stability and reproducibility.?2?Rare earth oxide Dy₂O₃-Au NPs composite nanomaterials-based electrochemical sensor for sensitive determination of nitrite Dy₂O₃-Au NPs based composite nanomaterials were synthesized and employed for electrochemical non-enzyme determination of Na NO2.The obtained products were characterized by TEM,UV-vis absorption and XRD.The electrochemicalproperty of the Dy₂O₃-Au NPs was full investigated.By utilization between the electrocatalytic property of Dy₂O₃ and the good conductivity of Au NPs,the fabricated electrochemical sensor exhibited excellent electrochemical catalytically oxidation of Na NO2.Under the optimal conditions,the oxidation peak current increased linearly with the Na NO2 concentration in the range of 0.01¹.0 mmol×L-1 with the detection limit of 3.3 ?mol×L-1.The linear regression equation is Ipa??A?= 6.70 + 51.1 C?mmol×L-1?,R2=0.965.Furthermore,the sensor showed the excellent selectivity towards the detection of Na NO2 and good reproducibility.When employed for the real sample analytical application,it owned appropriate recovery of Na NO2 in water samples,indicating the potential application of the fabricated sensor for the detection of nitrite in real samples.?3?Synthesis,characterization of n-Nd F₃ and its electrochemical detection for uric acid Globular n-Nd F₃ was synthesized via hydrothermal method,which was modified onto glassy carbon electrode in order to fabricate a novel biosensor for detection of UA.Meanwhile test measures of energy spectrum?EDS?,scanning electron microscope?SEM?and XRD were applied to analysis the structure and size of n-Nd F₃.CV was employed to research biological nature of the biosensor.The results reveal that n-Nd F₃ has good biocompatibility,which can realize direct electron transfer between uric acid molecule and the surface of electrode.Detection range of was 0.05¹.0 mmol×L-1,the lowest detection limit?S/N=3?was 16.67 ?mol×L-1.?4?Simultaneous determination of dopamine,ascorbic acid and uric acid based on the composite materials of GO and n-Tm PO₄ Depending on the characteristics that grapheme oxide?GO?with nanomaterial can accelerate electron transfer both enzyme and electrode,GO and n-Tm PO₄ were synthesized via improved Hummers and hydrothermal method respectively.Characterization and analysis were for GO and n-Tm PO₄,GO/n-Tm PO₄ modified electrode was fabricated.Then differential pulse voltammetry?DPV?was employed for studying the electrochemical behaviors of ascorbic acid?AA?,dopamine?DA?and uric acid?UA?on the modified electrode.The experimential results indicated that GO and n-Tm PO₄ had synergistic effect.The biosensor successfully achieved potential separation between AA,DA and UA.