Design And Development Of Conducting Polymer Microneedle Sensor

Diabetes seriously affects normal daily life.The monitoring of glucose in human is a necessary part of the therapy of diabetes.The chief task in this work is to fabricate a microneedle electrode that can be used for continuous blood glucose monitoring.By taking advantage of the non-invasive characteristics of microneedle and fixing the microneedle electrode on the skin with the help of related technologies,the goal is to achieve continuous detection of blood glucose in patients.The research outline in this work are as follows:1.Fabricate a polymer poly lactic acid microneedle electrode.First,a poly lactic acid microneedle substrate is made by a template hot pressing method.And chromium and gold are sputtered on the microneedle substrate to make the substrate have conductivity.Subsequently,pyrrole was polymerized on the electrode by electrochemical method.The peroxidation process was achieved by potentiostatic method.Subsequently,gold nanoparticles were deposited on the MN electrode by electrochemical method similarly.Glucose oxidase was coated on microneedle surface,and then Nafion was applied on the electrode.The microneedle electrode surface part was studied with optical microscope and SEM.Dynamometer was used to study microneedles penetrate the skin.The results of electrochemical polymerization time of pyrrole monomer,electrochemical deposition time of gold nanoparticles,experimental temperature,and the amount of GOx on the detection performance of microneedle electrodes were also studied.2.The actual detection performance of the microneedle sensor.The electrochemical workstation is mainly used for microneedle sensor glucose testing in different samples.The experimental results show that the microneedle sensor can linearly detect 0-2.6 mM glucose in PBS solution,the sensitivity is 8.09 μA/mM,the detection limit is 40 μM,response time～28 s,and there is still more than 90%response stored in the PBS solution for 14 days.And it has good anti-interference to common interfering substances.In the skin model gel test,the microneedle sensor can detect different glucose concentrations(0-2 mM).In artificial interstitial fluid,the microneedle sensor has a linear range of 0-2 mM for glucose.In actual samples,using mouse plasma as the test substrate,the microneedle sensor can detect glucose with a range from 0 to 2 mM.Protein adsorption affects microneedle sensor performance.Electrochemical impedance spectroscopy method was applied to determine the impact of protein.Experiments show that the microneedle electrode adsorbs protein,the surface impedance of the electrode rises,and the response to glucose declines.The microneedle can detect a high content of glucose.