Imaging of electrochemical enzyme sensor on gold electrode using surface plasmon resonance.
Three types of imaging, namely layer structure, electrochemical reaction, and enzyme sensor response, were achieved by applying surface plasmon resonance (SPR) measurement to an electrochemical biosensor. We constructed glucose oxidase based mediator type sensors on a gold electrode by spotting the mediator that contained horseradish peroxidase and spin coating the glucose oxidase film. The layer structure of the sensor was imaged by means of angle scanning SPR measurement. The single sensor spot (about 1 mm in diameter) consisted of about 100 x 100 pixels and its spatial structure was imaged. The multilayer structure of the enzyme sensor had a complex reflectance-incident angle curve and this required us to choose a suitable incident angle for mapping the redox state. We chose an incident angle that provided the most significant reflection intensity difference by using data obtained from two angle scanning SPR measurements at different electrode potentials. At this incident angle, we controlled the electrochemical states of the spotted mediator in cyclic voltammetry and imaged the degree to which the charged site density changed. Finally, we mapped the enzymatic activity around the mediator spot by the enzymatic reoxidation of pre-reduced mediator in the presence of glucose.
NTT Lifestyle and Environmental Technology Laboratories, NTT Corporation, 3-1, Morinosato Wakamiya, Kanagawa 243-0198, Atsugi, Japan. iwasaki@with.brl.ntt.co.jp
Yuzuru
Y
Iwasaki
Tatsuya
T
Tobita
Kazuyoshi
K
Kurihara
Tsutomu
T
Horiuchi
Koji
K
Suzuki
Osamu
O
Niwa
D015374:Biosensing Techniques / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004789:Enzyme Activation; D004798:Enzymes / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase / Q000737:chemistry* / Q000648:ultrastructure; D006046:Gold; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties
D020099:Coated Materials, Biocompatible; D004798:Enzymes; D004800:Enzymes, Immobilized; D006046:Gold; D005949:Glucose Oxidase; D005947:Glucose