Preparation Of Ternary Metal Oxide Nanomaterials And Its Application In The Detection And Treatment Of Diabetes

Diabetes has become one of the most important health problems in the world in the 21st century.The daily management of diabetes is related to the normal life of hundreds of millions of patients.Continuous blood glucose monitor is becoming an important means of diabetes mellitus management,it can real-time,accurate detection of blood glucose levels,and control of insulin injection dose.In order to achieve these goals better,it is necessary to study the preparation of glucose biosensors with higher sensitivity,faster response speed,greater linear range and higher stability,and to study the preparation of carriers for diabetes-related drug loading and controlled release.To this end,we have done the following three aspects of research work:(1)Preparation of new materials.Starting from the selection and preparation of new materials,we prepared ternary metal oxide nanomaterials,including KNbO3,LiNbO3,NiCo2O4 and CoFe2O4 nanomaterials,and improved the properties of ternary metal oxide based biosensors using gold nanoparticle modification.First,we prepared the KNbO3 nanoneedle by hydrothermal method and applied it to the detection of enzyme hydrogen peroxide.Perovskite non-central symmetrical structure of the KNbO3 nanoneedles can effectively promote the separation of carriers.The co-catalysis of KNbO3 and horseradish peroxidase on hydrogen peroxide can be achieved by the formation of σ-bonding between the eg orbital of surface niobium ions and the surface adsorbed oxygen intermediates.The detection sensitivity of enzyme-based hydrogen peroxide biosensor based on KNbO3 nanoneedles was 750 μA·mM-1 ·cm-2,the linear range was 0.04～6 mM,and the rapid response to hydrogen peroxide was achieved in 1～2 s.The gold nanoparticles can effectively promote charge separation and electron transport after the gold nanoparticles are modified on the KNb03 nanoneedles.The detection sensitivity of the enzyme-free hydrogen peroxide biosensor was 318.2 μA·mM-1·cm-2,which was 64%higher than that of KNbO3 nanoneedles.Secondly,LiNbO3 nanoparticles and nanotubes were prepared by melt salt method and bio-template method respectively,and they were applied to enzyme-derived glucose biosensor.LiNbO3 has the greatest self-polarization strength,which can better promote the separation of carriers.LiNbO3 nanotubes prepared by bio-template method have more specific surface area,mesopores and folds than LiNbO3 nanoparticles,which is favorable for the immobilization of enzyme molecules.It provides a suitable microenvironment for maintaining enzyme activity,while its one-dimensional tubular structure is also beneficial to the sufficient contact between the reactants and the enzyme molecules.Therefore,the enzyme biosensor based on LiNbO3 nanotubes has better performance,and its detection sensitivity reaches 52.4 μA·mM-1·cm-2,which was 86.5%higher than that of LiNbO3 nanoparticles.Ranging from 0.3 to 3.3 mM,enabling rapid response to glucose within 2 s.Thirdly,NiCo2O4 nanomaterials were synthesized by hydrothermal method on titanium substrate and applied to enzyme-free glucose biosensor.With the increase of the hydrothermal temperature,the morphology of NiCo2O4 nanomaterials changed from nanosheets to nanowires,and their biosensor properties were measured respectively.It was found that NiCo2O4 with nanosheet/nanowire composite structure had the greatest detection sensitivity to glucose,up to 1530 μA·mM-1·cm-2.On the basis of this,the concentration of F-ions in the preparation process was increased,and the detection sensitivity of the glucose biosensor was 2387 μA·mM-1·cm-2,which was 1.23 times higher than that before.After the gold nanoparticles were modified on the NiCo2O4 nanosheet,the detection sensitivity of the enzyme-free glucose biosensor was 2979μA·mM-1·cm-2,which was 24.8%higher than that of the NiCo2O4 nanosheet biosensor.Finally,hollow CoFe2O4 porous microspheres were synthesized by hydrothermal method and applied to the colorimetric glucose biosensor.The growth process of hollow CoFe2O4 porous microspheres can be explained by in situ dissolution and recrystallization by reaction time series experiments.According to the change of the visible light absorption peak at 652 nm using TMB reagent,we achieved the colorimetric detection of glucose with CoFe2O4,and the linear range was 0.67～6.67 mM.(2)Sensor integrated research.We combined with light conversion,energy storage and biosensing,and prepared the NiCo2O4/SnO2 all-solid self-driven glucose biosensor.Under light conditions,the photocurrent decreases linearly with the increasing of glucose concentration,and the linear range is 2 to 40 mM.In the absence of light conditions,the chemical energy stored in the storage electrode can oxidize glucose,the open circuit voltage and glucose concentration showed a good linear relationship,the linear range was 2～12 mM.(3)Drug loading and release studies.We prepared the hollow CoFe2O4 porous microspheres with a high specific surface area,with a drug loading efficiency of 88.6%and 118.1 mg of DOX drug per gram of CoFe2O4 microspheres.At acidic pH,DOX-loaded CoFe2O4 microspheres have faster drug release rates and greater drug release.CoFe2O4 has strong magnetic properties,and the release of drugs can be controlled under the alternating magnetic field.With the increasing of alternating magnetic field frequency and intensity,the cumulative drug release of CoFe2O4 drug carrier increased at the same time.The study of CoFe2O4 based drug carriers has laid the foundation for future studies on insulin loading and release.