Needle-type Glucose Biosensor Based On Conducting Polymer

Diabetes is a serious chronic disease and one of the largest global health emergencies,appropriate blood glucose(BG)management is of vital importance for diabetes patients and is also a necessary basis for insulin therapy.However,traditional finger-prick BG tests associate with pain,which lower the patient's compliance and lead to inappropriate BG management and finally result in incorrect treatment.The development of continuous blood glucose monitoring devices can not only reduce the suffering of patients in finger-prick testing,but also provide more comprehensive data of BG levels,therefore,patients can have better knowledge and understanding on their conditions,which can further provide correct treatment regimens and lower the risk of complications.In this study,glucose oxidase was used as a bioactive molecule that specifically recognized glucose to construct a novel glucose sensor based on conducting polymer.Firstly,a three-electrode system was printed on a polyethylene terephthalate(PET)substrate by using the screen printing technique,in which both the working electrode and the counter electrode were graphene conductive carbon paste,and the reference electrode was Ag/AgCl,and the three electrodes were arranged layer by layer.Then the working electrode was modified by electrochemical method.The results showed that the glucose sensor with glucose oxidase immobilized polypyrrole film on the surface of the working electrode could linearly respond to glucose PBS solution in a concentration range of 1-10 mM.It could still work effectively after a 30-day storage at both dry and wet conditions,however,of which the stability and sensitivity were relatively low.By pretreating the working electrode with a layer of gold nanoparticles,the performance of the sensor could be effectively improved,and the sensitivity increased from 8.274 nA/mM to 14.453 nA/mM and response time decreased from 30 s to 25 s compared with the group without pretreatment.In addition,the influence of monomer/dopant ratio,polymerization charge,and polymerization potential on the performance of the sensor had also been studied.The results indicated that there was an optimal value for these three factors,namely,higher or lower than this optimal value would lead to a decline in the performance of the sensors.