Study Of Glucose Sensing Performance Based On Sputteringconstructed Micro-Nano Electrodes

Non-invasive electrochemical analysis of the concentration of glucose molecules in human biospecimen such as sweat and saliva can not only greatly reduce the risk of infection caused by conventional blood sampling from veins or fingertips,but also realize real-time monitoring of human physical health.However,since the glucose concentration in biospecimen such as sweat and saliva is much lower than that in blood,the sensitivity of existing glucose sensors cannot meet the demand for non-invasive blood glucose monitoring.Construction of micro-nano electrodes is an important means to improve the electrocatalytic reaction activity and surface area of electrode materials,and thus enhance the glucose sensing performance.In view of this,this work presents a method to construct micro-nano electrodes by ion beam sputtering and magnetron sputtering,and then clarify the influence of the micro-nano electrode structure on the performance of glucose sensing.The specific research work is as follows:（1）A method of preparing small-sized Au nanoparticles（～3.4 nm）by ion beam sputtering is proposed.During the ion beam sputtering process,Au nanoparticles were self-assembled on the surface of the sensor electrode to construct a microstructure with higher catalytic activity.The nanoelectrode structure was found to improve the charge transfer rate between the electrode and the glucose.The influence of the ion beam sputtering time of Au nanoparticles on the sensitivity of the glucose sensor was revealed further.As the sputtering time was 60 s,the sensitivity of the sensor increased from the initial state of 85.7μA/m M to 216.9μA/m M,and the detection limit was 1μM.This result means that the sensitivity is high enough to detect a small concentration of glucose in saliva,and the device has a good selectivity for glucose molecules.In addition,the glucose sensing performance was also improved by sputtering Au nanoparticles on the conductive carbon film,indicating that this method has good versatility.（2）In order to reduce the cost of Au nanoparticles modified electrodes,Cu nanoparticles were sputtered on a metal electrode by the magnetron sputtering method.By changing the sputtering processing parameters,Cu nanoparticle sizes and its stacking structure on the metal electrode were tuned.As the sputtering time was 40 s,the sensor sensitivity based on the Cu-nanoparticle-modified electrode increased from 85.7μA/m M to 219.4μA/m M,and the detection limit was 1μM,which is close to the concentration of glucose in saliva.（3）The glucose oxidase enzymes in the above sensors degrade fast to lose their activity in the environment.In view of this,an enzyme-free glucose sensors based on the Cu Al₂ electrodes was constructed by magnetron sputtering.By co-sputtering Cu and Al,the Cu Al₂ alloy films with（112）highly preferred crystal plane orientation were prepared.And then,the Cu Al₂ alloy film was corroded by an electrochemical method.When the corrosion time was 350 s,the sensitivity of the Cu Al₂ micro-nano electrode sensor increased from 146.6μA/m M to 2319.6μA/m M,and the detection limit was 0.3μM along with an improved response speed.