Fabrication And Study Of Performance Of Nonenzymatic Glucose Sensor Based On Pt-based Micro-nano Structure

The poor sensitivity, repeatability and stability of the enzymatic sensors remainas problems for real sensor applications. Direct electrocatalytic oxidation of glucose atan enzyme-free electrode would exhibit conveniences and advantages to avoid thedrawbacks of the enzymatic electrode. Therefore, the development of needle-typenonenzymatic glucose biosensor provides a promising method for glucose detection.Pt nanofowers were fabricated by using template-free ultrasonicelectrodeposition method. The Pt nanofowers electrode exhibited excellent catalyticactivity towards glucose oxidation in the present and in the absence of chloride ions.The results showed that the sensitivity of the electrode to glucose oxidation was1.87μAcm^-2mM^-1with a linear range from1mM to16mM and detection limit of48μM.In addition, the nonenzymatic glucose sensors exhibited excellent selectivity, stabilityand repeatability. This indicated that nanoflower structure exhibit advantages to avoidthe drawbacks of bare Pt electrode, and thus selectivilty, sensitivity, stability andrepeatability of the sensors can be improved.Pinecone–shaped Pt–Pb nanocone electrode was prepared on the bare Auelectrodes by electrochemical deposition. The synthesized pinecone–shaped Pt–Pbnanocone electrode exhibited strong and sensitive current responses to glucose at anegative potential in the present and in the absence of chloride ions. In the Pt–Pbbinary system, Pb can considerably accelerate glucose electrooxidation at Ptelectrodes but it exhibited no direct catalytic effect towards glucose. Therefore,glucose oxidation at the Pt–Pb mainly followed the reaction pathway of glucoseoxidation at Pt electrode. The sensitivity of the sensor was10.71μAmM1cm2withlinearity up to12mM and a detection limit of8.4μM. In addition, the as–preparednonenzyme glucose sensor exhibited acceptable repeatability, stability andreproducibility for determination of glucose. The response current increased with thetemperature in the range from20oC to70oC, and became stable when thetemperature was above70oC. Therefore, the sensor exhibited a wide range ofapplications compared with enzymatic biosensor.Pt–Ag and Pt–Cu hollow nanoparticles were fabricated by galvanic replacement.Electrochemical results showed that Cu and Ag can considerably accelerate glucoseelectrooxidation at Pt electrodes, but the electrooxidation potential increased. Thesensitivity of the sensor based on Pt–Ag hollow nanoparticles was7.64μAmM1cm2 with linear range from0.5mM to16mM and a detection limit of11.78μM. Thesensitivity of the sensor based on Pt–Cu hollow nanoparticles was8.04μAmM1cm2with linear range from0.5mM to14mM and a detection limit of11.19μM. Thenonenzymatic sensors based on Pt–Ag and Pt–Cu hollow nanoparticles showedacceptable stability and repeatability.An enzymatic glucose biosensor was fabricated by electrodepositing chitosan–glucose oxidase biocomposite onto the stainless steel needle electrode modifed byPt–Pb nanoparticles. The linear range of the proposed biosensor was from0.03to9mM with a current sensitivity of0.4485μAmM1and a detection limit of200μM.This work confirmed that the fabrication method of the needle-type glucose biosensorwas feasible.A nonenzymatic glucose biosensor was fabricated by electrodepositing Pt–Pbnanoparticles onto the stainless steel needle electrode. The results showed that thesensitivity of the electrodes to glucose was3.33μAcm^-2mM^-1with liner range from1.5mM–24mM and detection limit of27μM. In addition, the nonenzymatic glucosesensors exhibited excellent selectivity, stability and repeatability. Compared with theenzymatic glucose biosensors, the nonenzyme sensors exhibited high stability,sensitility and repeatability.