A Hirarchial Cobalt/Carbon Nanotube Hybrid Nanocomplex-based Ratiometric Fluorescent Nanosensor For Ultrasensitive Detection Of Hydrogen Peroxide And Glucose

Hydrogen peroxide is one of the food additives which used for food bleaching,disinfection,and sterilization.It is widely used in food production and processing.Traces of hydrogen peroxide can be slowly decomposed by itself and have little effect on human health.However,excessive use of hydrogen peroxide even with industrial-grade hydrogen peroxide can cause excessive levels of hydrogen peroxide in foods,which greatly threatens the health and security of consumers.Glucose is the most important dietary saccharide source of energy from natural carbohydrate.Disorders of glucose metabolism can lead to a series of health problems,such as hyperglycemia and hypoglycemia.In clinical or healthcare perspective,the measurement and control of glucose level in blood is of particular importance for diabetic patients to regularly monitor the concentrations and make fast and accurate determination of glucose levels.So,the development of a rapid and sensitive method for detection of H2O2 and glucose are important and highly desirable.A ratiometric sensor can simultaneously afford two readout signals with reverse change tendency endowing it capability to reduce false results and thus improve detection accuracy.Herein,a novel ratiometric fluorescent nanosensor for ultrasensitive detection of hydrogen peroxide and glucose has been constructed based on peroxidase-like property of hirarchial cobalt/carbon nanotube hybrid nanocomplex(Co-CNT)synthesized with MOF-67 as precursor.The as-prepared Co-CNT can catalyze non-fluorescent substrate of amplex red(AR)into fluorescent substrate while the fluorescent substrate of scopoletin(SC)into non-fluorescent substrate in the presence of H2O2.The sensing system is converted from yellow to blue,which can be clearly seen with naked eyes.With the fluorescence ratio of AR to SC as readout,detection limit of H2O2 reaches as low as 100 nM.The developed assay is further utilized for determining H2O2-related oxidase reactions with glucose and glucose oxidase system as model.Glucose can be selectively and sensitively detected as low as 150 nM.Satisfactory recoveries(93%-105%)are obtained for glucose detection in serum samples.The developed assay is simple in preparation and operation and provides a straightforward way for cost-effective and reliable detection of H2O2 and H2O2-related reactions in clinical diagnosis and biomedical applications.