Effect of Stress Intensity Factor on Crack Growth Rate应力强度因子的裂纹扩展速率的影响.pptVIP

Carbon Nanotubes as Biosensors ME 695 Yang Yang 11/30/2004 Outlines Introduction Amperometric biosensors Carbon nanotube-modified amperometric biosensors Conclusion References Introduction Materials for Biosensors 1. inert metals( Pt. Gold) 2. carbonaceous materials( graphite, carbon fibers, glassy carbon and carbon nanotubes) Introduction Carbon Nanotubes Fabrication- catalytic chemical vapor deposition (CVD) method Introduction Amperometric biosensors Biosensors: 1. converts a biological response into an electrical signal; 2. for determine the concentration of substances and other biological parameters. Amperometric biosensors Amperometric biosensor Carbon nanotube-modified amperometric biosensors Preparation of carbon-nanotube electrode with Pt nanoparticles Carbon nanotube-modified amperometric biosensors Current response to successive injection of 0.1 mM hydrogen peroxide 1-5: CNT electrodes; 6: Graphite electrodes CNT electrodes more electrocatalytic active than Graphite electrodes Carbon nanotube-modified amperometric biosensors Current response to successive injection of 0.1 mM hydrogen peroxide 2(0.2V)-3(0.6): Pt/CNT electrodes; 1(0.6V): Pt/Graphite electrodes Response behavior of Pt/CNT at 0.6 V Much better than Pt/Graphite Comparing curve 3 in (b) and curve 1 in (a), Pt nanoparticles greatly improves the electrocatalytic activity. Carbon nanotube-modified amperometric biosensors Current response to successive injection of 0.1 mMglucose Curve 1: Nafion/GOD/CNT Curve 2: Nafion/GOD/Pt/CNT Potential 0.6 V Pt/CNT composite better for immobilization of GOD than CNT/Graphite Carbon nanotube-modified amperometric biosensors Another method of preparing CNT-based Glucose electrode 1. Wash MWCNT, polish the surface of basal plane pyrolytic graphite(bppg) electrode; 2. Rubbing electrode with filter paper containing 2 mg MWCNT for 1 min. 3. Mixing 50 miuL sol-gel composite solution with 50 miuL glucose oxidase solu