Two-Dimensional Carbon-Based Nanomaterials-Based Biosensor Technology For The Detection Of Hydrogen Peroxide And Glucose

With the development of science and technology,along with the continuous development of life science,the research of life science is also progressing,simple,real-time,and the accurate detection of important biomolecules,such as protein,enzymes,sugars,and small molecules,has a vital significance to the field of medical diagnosis,food analysis,biotechnology,environmental monitoring and protection etc.Because of their unique optical,electronic,and catalytic response characteristics,nanomaterials have become a new and promising sensing platform for bioanalytical applications.Nanobiosensors,which combined nanomaterials with biosensors,have involved many applications including chemical and biological technology,nanoscience,interface science as well as other interdisciplinary,and embody significant advantages in basic theory of biological sensor.Hydrogen peroxide?H₂O₂?,an important biochemical molecule,plays a critical role in the regulation of various physiological processes.Glucose is the main source of energy in cell metabolism,and plays an important role in cell growth.The intracellular H₂O₂ accumulation or disorder can lead to many serious diseases,such as central nervous system disease or cancer.And monitoring blood glucose level and blood glucose levels in diabetes is closely related to health problems,so the development of a rapid and sensitive nanomaterials-biosensor for detection of H₂O₂ and glucose are important and highly desirable.In this thesis,we uses the two-dimensional nanomaterials of graphene oxide and graphite carbon nitride,starting from the study of its unique properties,and then to the development of simple,fast,efficient and sensitive new sensors to detect H₂O₂ and glucose.The research contents are summarized as following:In the second chapter,we first established a g-C₃N₄ based ratiometric fluorescent probe for highly sensitive detection of hydrogen peroxide and glucose.Under the catalysis of horseradish peroxidase?HRP?,phthalate two amine?OPD?by H₂O₂ oxidation to the corresponding oxidation products?oxOPD?,g-C₃N₄ nanosheets,with high surface area and large ? system,generated oxOPD assembled on the surface of g-C₃N₄ nanosheets by hydrogen bonding and ?-? stacking interactions,througth the light induced electron transfer?PET?,oxOPD not only quenches the fluorescence of g-C₃N₄ nanosheets,but also emits a new fluorescence peak.Measuring the ratio of fluorescence signal can detect H₂O₂ senstively.Because glucose can produce H₂O₂ under the catalysis of glucose oxidase.the method can be further applied to the detection of glucose.The development of the analysis method for H₂O₂ and glucose in this chapter push detection limit to 50 nM and 0.4?M,respectively,and this method also has good selectivity.The sensing strategy provides a high throughput detection platform involving the H₂O₂-generating reactions.In Chapter 3,we assembled DNA on the surface of graphene?GO?and synthesized AgNPs directly under the guidance of DNA on the surface of GO to obtain nanocomposites?AgNPs-DNA@GO?.In the nanocomposites,due to the double quenching effect of AgNPs,DNA fluorescence greatly weakened.When H₂O₂ is added,H₂O₂ interacts with AgNPs to produce hydroxyl radical?.OH?,which can effectively destroy AgNPs and cleave DNA,which leads to the dissociation of nanocomposites and the final fluorescence recovery.