Construction And Performance Of Nano/Micro-sensors For The Detection Of Biomarkers For Diabetes

Diabetes mellitus is a global public health problem.Due to the elevation of glucose concentration in blood,it often increases the risk of renal failure,blindness,heart disease,limb amputation and other complications.Therefore,the daily monitoring of diabetes is very important for the management and control of the disease.In recent years,electrochemical glucose biosensors and exhaled acetone gas sensors for diabetes biomarkers have been widely studied.Compared with the traditional complex inspection process in hospitals,the portable and accurate point-of-care（POC）sensing devices will make the daily monitoring of diabetes more convenient.As the core component of a sensor,the sensitive material plays an important role in sensor performance.So far,a large number of nano/micro-structured materials have been proved to have catalytic properties similar to enzymes.Compared with conventional enzymatic biosensors,the preparation method of non-enzymatic biosensors is simpler.Besides,the non-enzymatic biosensors are cheaper,more stable and have better catalytic activity.Among them,bimetallic oxide nano/micro-materials with spinel structure have excellent conductivity and electrocatalytic activity due to the synergistic effect of metal ions with various valence states which is conducive to the transmission of electrons.Therefore,they have much potential to apply in the sensitive elements of diabetes sensors.In this paper,two electrochemical glucose sensors and an acetone gas sensor were constructed based on bimetallic oxide materials.The catalytic performance of the sensing materials for glucose or acetone was studied.The optimal test conditions,sensitivity,detection limit,anti-interference and stability of the sensors were investigated.The main content is divided into three parts:（1）To construct a 3D electrochemical glucose sensor without adhesive,Zn Co₂O₄nanosheet arrays（Zn Co₂O₄NSAs）directly grew on the biocompatible flexible carbon cloth via hydrothermal and annealing methods.The results of electrochemical performance test showed that Zn Co₂O₄NSAs/CC had a good response towards glucose in alkaline conditions,with a sensitivity of 2004μA m M^-1cm^-2,a detection limit of 1.14μM,good selectivity and stability.This preparation method is simple and easy to operate,which lays a foundation for the design of other bimetallic oxide electrodes with high performance.（2）Layered NiCo₂O₄ nanowires@NiMoO₄nanosheets core-shell hybrid arrays were synthesized in situ on carbon cloth by a two-step hydrothermal and annealing method to be used for enzyme-free glucose sensing.Compared with pure NiCo₂O₄nanowire arrays electrode,the hybrid arrays showed better catalytic activity for glucose.The optimal working potential was 0.50 V.And when the glucose concentration was 0-0.8 m M,it had a good sensitivity of 9557μA m M^-1cm^-2.Furthermore,the detection limit was as low as 0.24μM.（3）Zn₂SnO₄/SnO₂ microboxs were synthesized by coprecipitation and annealing process,and the gas sensor was prepared for acetone measurement.The results showed that the sensor had a good selectivity towards acetone.It had a sensitivity of 20.4 at the best working temperature of 250°C.In addition,the detection limit was much lower than the exhaled volume of diabetic patients（1.8ppm）.Therefore,It has a broad application prospect in the painless diagnosis of respiration in diabetes mellitus.