Diaphorase immobilized image

FIG. 21 SECM image of a diaphorase-immobilized substrate with a deactivated line formed by scanning an UME while generating bromine across the surface. (From Ref. 41.)... 

Figure 1. An SECM image of the substrate with diaphorase immobilized (upper) and its cross-section (lower).

FIGURE 15.26 SECM image of a diaphorase-immobilized substrate with a deactivated line formed by scanning an UME while generating bromine across tbe surface. (Reprinted with permission from Shiku, H., Takeda, T., Yamada, H., Matsue, T., and Uchida, I., Anal. Chem., 67, 312, 1995. Copyright 1995 American Chemical Society.)... 

SECM was used for the fabrication of diaphorase-pattemed surfaces (134). Diaphorase, a flavin enzyme, was immobilized on glass surfaces. The oxidation of Br or Cl at the tip generated a reactive species, which deactivated the enzyme molecules on glass forming unreactive patterns. The circular and Unear patterns were then imaged by SECM based on the detection of catalytic current of feirocenylmethanol coupled with oxidation of DADH. 

Diaphorase enzyme and diaphorase/albumine mixtures immobilized on the surface of a glass plate were imaged by Yamada [123] and coworkers using platinum disc tips. FcMeOH redox mediator and NADH reagent were used in these studies. The FcMeOH was oxidized at the platinum tip. The immobilized diaphorase catalyzed the oxidation of NADH by FcMeOH" the oxidized form of FcMeOH. So, if the tip was near to the catalytic surface, then the enzyme catalyzed reaction increased the local concentration of FcMeOH. That positive feedback generated increase of the current showed the active enzyme spots on the sample surface. 

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