Study On Preparation And Properties Of A Novel AuAg@BSA Non-enzymatic Glucose Electrochemical Sensor

Rapid and accurate measurement of blood glucose concentration is a key step in the prevention and treatment of diabetes.At present,the household glucose detectors with enzyme glucose sensors are susceptible to environmental influence and are poor stability.The non-enzyme glucose electrochemical sensors can show good stability and sensitivity.However,the preparation methods of most non-enzymatic glucose sensors with excellent comprehensive performances are relatively complex and costly.It is one of the important research directions to develop a non-enzymatic glucose electrochemical sensor with high sensitivity,wide linear detection range,low detection limit,and low cost.Au is an important catalyst for electrocatalysis of glucose,but the catalytic performance of Au-based glucose sensor needs to be further improved.Therefore,the Au-based non-enzymatic glucose sensors with high sensitivity and wide detection linear range are prepared by a simple method.The catalytic performances of the AuAg-based non-enzyme glucose sensors are further improved by Ag doping,and the comprehensive performance and stability of the sensor are excellent.Furthermore,the adsorption properties of Au and AuAg substrates for glucose molecules under alkaline environment were studied by density functional theory.The main research contents are as follows:(1)The electrochemical performances of the Au cluster film non-enzymatic glucose sensors prepared under six alkaline conditions were studied.The sensitivity and linear detection range of the Au cluster film sensors were significantly increased compared with the traditional acidic conditions.The Au cluster film prepared at pH 12 presents a multi-layer 3D structure composed of a large number of Au nanoparticles,which exhibits a large specific surface area and brings many electrocatalytic active sites.The ultra-high sensitivity of this sensor is 330.002μA/m M/cm~2.When the preparation condition is pH 8,the linear detection range of the sensor is the widest(0.1～128 m M),and the sensitivity is second only to that of pH 12.The adsorption properties of two kinds of Au substrate on glucose molecules under alkaline conditions were studied by density functional theory.The adsorption of OH~-is stronger in icosahedral Au substrates,while the adsorption of glucose is stronger in cubic octahedral Au substrates under alkaline conditions.(2)The electrochemical performances of three kinds of AuAg non-enzymatic glucose sensors prepared at pH 12 were studied.The sensitivity and stability of the Au cluster film sensors are improved by doping Ag,and the cost reduction.The sensitivity of Au1Ag1 and Au3Ag1 cluster film sensors prepared in this paper reached 172.025μA/m M/cm~2and220.841μA/m M/cm~2under human normal blood glucose concentration,which were 65.7%and 112.8%higher than that of pure Au cluster film sensors,respectively.The Au1Ag1cluster film sensor has strong stability,maintaining a sensitivity close to 90%after storage for 30 days in the air at room temperature.The adsorption properties of four different proportions of AuAg substrates on glucose molecules under alkaline conditions were studied by density functional theory.Compared with pure Au substrate,the adsorption of AuAg substrate for OH~-is relatively weak.The glucose adsorption of the Ag site in the same AuAg substrate is stronger than that of the Au site under alkaline conditions.The adsorption of glucose on Ag sites of all AuAg substrates is stronger than that on pure Au substrates,which means that the doping of Ag improves the adsorption of glucose on pure Au substrates.With the increase of the proportion of Ag,the adsorption capacity of AuAg substrate to glucose fluctuated.