| Biosensor technology is a kind of biological analysis technology with strong specificity and high sensitivity.The development of Biosensor has experienced three generations: enzyme electrode,intermediate enzyme electrode and electrochemical biosensor.It shows unique advantages in food safety,environmental monitoring and health diagnosis.However,the traditional biosensors are based on plastic,glass and so on,which are non-renewable,difficult to degrade,and inconvenient to carry.Although paper-based biosensor is green and environmentally friendly,it is easy to permeate liquid due to the large porosity of paper,which affects the efficiency of detection.Therefore,it is necessary and meaningful to develop a new type of substrate material for green and environmental protection.Nanocellulose is a kind of natural biomass nanomaterials with nanometer diameter,high mechanical strength,high aspect ratio,biodegradable,renewable and abundant raw materials.Nanocellulose paper based on it has the advantages of flat substrate,small porosity,transparency and large specific surface area.It is a potential substitute for traditional biosensor substrate.In this study,the abundant but underutilized shrub resources were used as the raw materials,the Amorpha fruticosa was selected as the research object,the nanocellulose was extracted by chemical and enzymatic pretreatment,and the optimization method was screened out.Then,based on the selected nanocellulose as the construction unit,a transparent nano-paper/membrane with basement formation and low permeability is formed,and a colorimetric biosensor and an electrochemical biosensor are designed to verify the concept of rapid detection of glucose.The results show that:(1)In order to find out the optimum time of cellulose by enzymatic pretreatment,the nanocellulose with a diameter of about 3 nm was obtained by neutral TEMPO oxidation,and the nanocellulose with a diameter of about 6 nm was got by alkaline TEMPO oxidation method.Two kinds of TEMPO oxidation methods(alkaline system and neutral system)were optimized by comparing the structure of nanocellulose in three ways.(2)Using alkaline TEMPO oxidation to extract nanocellulose from synthetic cellulose,transparent nanopaper was made,and a colorimetric biosensor was constructed on the surfaceto detect the content of glucose in sprite and sea-speaking beverages.By comparing the standard DNS method and Colorimetric method,the content of glucose in the 138 of Sprite and Sea is 146.6 mg/ml and 89.9 mg/ml,respectively,and the difference is within the effective error range,The results show that the colorimetric biosensor constructed in this study can accurately,sensitively and rapidly determine the glucose content.(3)The nanocellulose was extracted from purified cellulose by neutral TEMPO oxidation,and the nanocellulose membrane was directly constructed on daily printing paper,which was used as the base of sensor,and then the electrochemical biosensor was designed by 3D printing sensor electrode,and was applied to the determination of glucose content.The content of glucose in grapefruit and pear fruits was determined by using ph=7.4 salicylic acid and electrochemical biosensor,respectively,for the acid-alkali environment,potassium iron as an electron probe,and glucose oxidase as catalyst.The glucose content in Pomelo was51.6mg/mL and 46mg/mL,and the glucose content in pear was 72 mg/mL and 67 mg/mL,respectively,which showed that the electrochemical biosensor designed by this study has the advantage of sensitive detection and fast and reliable.The results show that the design concept of nano cellulose paper based biosensor is feasible and can be used as a reference for future design and construction of new biosensor. |
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