Study On The Detection Of Glucose And 1,5-anhydroglucitol Based On Light-addressable Potentiometric Sensor

Diabetes mellitus is a major public health problem and one of the top four non-communicable diseases that countries around the world are prioritizing to tackle.At present,China has become the fastest growing region of diabetes in the world,and is also the largest country of diabetes in the world.Therefore,more and more attention has been paid to the diagnosis and monitoring technology of human blood glucose.In this paper,the biomarkers that can reflect human blood glucose level（glucose,1,5-anhydroglueitol（1,5-AG））were used as research subjects to explore cheap,convenient and highly sensitive detection methods.The main research contents are as follows:（1）Design of light addressable potential sensor（LAPS）signal detection system:A signal detection system for LAPS chip photocurrent detection is designed with power supply circuit,signal conversion circuit,bias voltage circuit,AC constant current source driving circuit,signal acquisition circuit,Ag/Ag Cl reference electrode,650 nm laser diode and LAPS platform.（2）Preparation of LAPS biosensitive membrane based on Reduction of graphene oxide-Chitosan-Ferrocene/Gold nanoparticles（RGO-CS-Fc/Au NPs）nanocomposites:Firstly,RGO-CS-Fc and Au NPs were synthesized.Then,the sensitive films with unique PROD/RGO-CS-Fc/Au NPs/LAPS and GOx/RGO-CS-Fc/Au NPs/LAPS composite structures were constructed,by using glucose oxidase（GOx）and pyranose oxidase（PROD）as the specific recognition molecule and combined with LAPS chip.（3）Study on the detection of glucose using LAPS biosensor based on RGO-CS-Fc/Au NPs nanocomposite:The detection of glucose was achieved by combining the glucose biosensitive membrane with the LAPS signal detection system.Under the optimal conditions,the glucose biosensor based on LAPS can detect glucose in the range of 0.01 mg/m L to 4 mg/m L.The linear equation isΔV₁=18.81345C₁+80.08747（whereΔV₁represents the potential shift of normalized I-V curve at normalized photocurrent 0.5of different glucose concentrations,and C₁represents glucose concentration）.The linear correlation coefficient was R²=0.98956,the sensitivity was 18.81345 m V/mg/m L,and the lowest detection limit was 0.01 mg/m L.In addition,the biosensor also showed good specificity,stability and reproducibility.The relative error of direct detection of serum samples ranged from 1.97%to 11.48%,which shows that the sensor has good practical detection performance.（4）Study on the detection of 1,5-AG using LAPS biosensor based on RGO-CS-Fc/Au NPs nanocomposite:The detection of 1,5-AG was achieved by combining the 1,5-AG biosensitive membrane with the LAPS signal detection system.Under the optimal conditions,the voltage shift of I-V curve of the LAPS is linearly related to the concentration of 1,5-AG at 10μg/m L-350μg/m L.ΔV₂=0.44273C₂+50.68317（whereΔV₂is the potential shift of the I-V curve at 0.5 of normalized photocurrent with different1,5-AG concentrations and blank control group and C₂is the concentration of 1,5-AG）.The linear correlation coefficient was R²=0.97414;The sensitivity was 0.44273 m V/μg/m L;The lowest detection limit is 10μg/m L.In addition,the sensor showed satisfactory recovery（91.28%to 107.66%）,long stability,good specificity and good reproducibility.