Au@MoS₂ Bifunctional Composite Properties And Applications In Enzyme-free Glucose Sensors

Glucose,as the main source of human energy,is an essential and important substance for human life activities.Diabetes occurs when blood sugar levels are above or below the normal range.At present,my country is the country with the largest number of people suffering from diabetes.In addition to middle-aged and elderly people who are prone to this disease,the number of young people with diabetes is also increasing.Diabetes is becoming“younger”,which is very detrimental to the health of our people.Therefore,the detection of glucose content plays a crucial role in the clinical diagnosis and treatment of diabetes.The glucose colorimetric sensor has the advantages of intuition and good selectivity,and the glucose electrochemical sensor has the advantages of fast response and no enzyme detection.Combining the two can better detect glucose.MoS₂and Au NPs have attracted much attention due to their peroxidase activity and glucose electrocatalytic activity.Meanwhile,MoS₂is an ideal material to stably support noble metals,and it is easily modified by Au NPs due to the Au-S bond.Therefore,in this paper,Au@MoS₂bifunctional composites were used to build colorimetric and electrochemical sensors to detect glucose.The details are as follows:（1）Au@MoS₂nanocomposites were successfully prepared by a combination of hydrothermal method and thermal reduction method,and their morphology,structure and Raman properties were characterized.The results show that the size of MoS₂nanoflowers is about 2μm,and the particle size of Au NPs is about 5 nm.The Raman signal intensity of Au@MoS₂nanocomposites is enhanced due to the plasmon resonance induced by Au NPs under the excitation of laser.The optimum molar ratio of the precursor HAu Cl₄·3H₂O to MoS₂is 1:8.（2）The peroxidase activity of MoS₂and Au@MoS₂was explored,and the detection performance of their glucose colorimetric sensor was discussed.The results showed that the Au@MoS₂nanocomposite had stronger peroxidase activity and better glucose detection performance.The optimal conditions were:p H 3,reaction temperature 35℃,TMB concentration 24 m M,Au@MoS₂dose 1 mg and reaction time 45 min.Meanwhile,the Au@MoS₂nanocomposite colorimetric sensor has a detection range of 0.001～1 m M,a detection limit of 0.01 m M,and good reusability and stability.（3）The AC impedance and cyclic voltammetry of MoS₂and Au@MoS₂electrodes were tested,and the detection performance of their enzyme-free glucose electrochemical sensors was discussed.Finally,the electrochemical sensor of Au@MoS₂nanocomposite material was compared with the colorimetric sensor,and the results showed that,Au@MoS₂electrode has better conductivity and glucose sensing performance,detection range of 0～25 m M,linear correlation coefficient of 0.99579,sensitivity of 417.556μA m M^-1,detection limit of 1 m M,and good reusability and stability.At the same time,Au@MoS₂nanocomposite glucose electrochemical sensor can achieve enzyme-free detection and has a wider detection range,but its detection limit is higher than that of colorimetric sensor.