Imaging of enzyme activity by scanning electrochemical microscope equipped with a feedback control for substrate–probe distance

Oyamatsu, Daisuke; Hirano, Yu; Kanaya, Norihiro; Mase, Yoshiaki; Nishizawa, Masatoyo; Matsue, Tomokazu

doi:10.1016/s1567-5394(03)00055-0

Cited by 56 publications

(39 citation statements)

References 13 publications

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“…where the redox couple represents Ru(CN) 6 Although the solvent used for the Fe(CN) 6 4− study was different from that of the other three reactants, the overall trend is consistent with the prediction of Marcus theory. Moreover, the effect of aqueous ionic strength was studied by the addition of salt to the aqueous by using approach curves of SECM .…”

Section: Etsupporting

confidence: 78%

“…The reorganization energy (  = 47.2 kJ mol− 1) was obtained from th best-fitting of the experimental curve. The ET reaction between TCNQ in 1, 2-dichloroethane (DCE) and Fe(CN) 6 3− in the aqueous phase was also studied (Fig. 6b).…”

Section: Etmentioning

confidence: 99%

“…The reorganization energy is 28.9 kJ mol −1 . Compared with the studies of the forward reaction between TCNQ in DCE and Fe(CN) 6 4− in the aqueous phase, the dependence of the back ET rate constants on…”

Section: Etmentioning

confidence: 99%

See 2 more Smart Citations

Electron Transfer Kinetics at Interfaces Using SECM (Scanning Electrochemical Microscopy

Lu¹,

Hu²,

He³

2012

Recent Trend in Electrochemical Science and Technology

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Section: Etsupporting

confidence: 78%

Section: Etmentioning

confidence: 99%

See 1 more Smart Citation

Electron Transfer Kinetics at Interfaces Using SECM (Scanning Electrochemical Microscopy

Lu¹,

Hu²,

He³

2012

Recent Trend in Electrochemical Science and Technology

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“…35,[41][42][43][44][45][46] Since the shear forces have to be measured in a viscous liquid, the signal change upon approach is rather small. Because long integration times have to be used, lateral translation rates are restricted.…”

Section: -25mentioning

confidence: 99%

Soft Stylus Probes for Scanning Electrochemical Microscopy

Cortés‐Salazar

Träuble

et al. 2009

Anal. Chem.

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A soft stylus microelectrode probe has been developed to carry out scanning electrochemical microscopy (SECM) of rough, tilted, and large substrates in contact mode. It is fabricated by first ablating a microchannel in a polyethylene terephthalate thin film and filling it with a conductive carbon ink. After curing the carbon track and lamination with a polymer film, the V-shaped stylus was cut thereby forming a probe, with the cross section of the carbon track at the tip being exposed either by UVphotoablation machining or by blade cutting followed by polishing to produce a crescent moon-shaped carbon microelectrode. The probe properties have been assessed by cyclic voltammetry, approach curves, and line scans over electrochemically active and inactive substrates of different roughness. The influence of probe bending on contact mode imaging was then characterized using simple patterns. Boundary element method simulations were employed to rationalize the distance-dependent electrochemical response of the soft stylus probes.Scanning electrochemical microscopy (SECM) is a scanning probe technique that provides spatially resolved detection of electrochemical and chemical surface reactivity.1,2 Typically, the probe is an amperometric disk-shaped ultramicroelectrode (UME) enclosed in an insulating sheath, e.g. glass. Due to the hemispherical diffusion occurring at the microdisc electrode, a steadystate current can be monitored as a function of the horizontal (x, y) and vertical (z) probe positions. SECM has found many applications ranging from surface reactivity imaging 3-13 to the study of the kinetics of homogeneous and heterogeneous reactions at solid/liquid, gas/liquid, and liquid/liquid interfaces. 14-20 Because the response of a SECM probe can be described by continuum models of mass transport coupled to electrochemical kinetics, quantitative kinetic information can be extracted by comparing experimental and simulated curves in many practically relevant situations. 21-25The response of a SECM probe depends on the surface reactivity of the sample and the distance d between the surface and the active area of the probe electrode. In order to obtain a reactivity image that is not influenced by topography, d must be kept constant. In conventional SECM operations, this is achieved by working on samples with a roughness that is considerably smaller than the radius r T of the UME and by leveling the plane of the sample surface with respect to the x,y-scanning plane of the positioning system. However, this approach becomes inappropriate on rough surfaces of large aspect ratios or when large scan areas (in the mm 2 range) have to be investigated so that leveling becomes a major obstacle. Similar limitations apply when imaging curved samples. This drawback has been recognized for a long time. In the case of a small r T , a constant d can be maintained by combining

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“…15 A carbon microdisk electrode (diameter, 7 µm), which was used as a probe, was prepared as described in previous papers. 11,17 Briefly, the carbon fiber inserted into a glass capillary was sealed by an epoxy resin (Oken Co., Tokyo). The top of the probe was carefully polished to obtain a sharper tip (angle, approximately 45°).…”

Section: Methodsmentioning

confidence: 99%

Improvement of Detectable Sensitivity for Enzyme Reaction by Scanning Electrochemical Microscopy with Distance Control System for Immunosensing

et al. 2012

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Detectable sensitivity for immobilized enzymes was improved using a constant-distance mode of scanning electrochemical microscopy (SECM). Redox species generated by an enzyme reaction captured via immunorecognition were detected with a microelectrode used as a probe. The probe maintained considerably close to the target surface (50 nm) allowed the enhancement of the current response because of cycling of redox species between the probe and the captured enzymes. The sensitivity of di(n-butyl)phthalate detection with a competitive assay by using constant-distance mode SECM was at least one order of magnitude higher than that of the probe scanned in a constant z-position.

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Imaging of enzyme activity by scanning electrochemical microscope equipped with a feedback control for substrate–probe distance

Cited by 56 publications

References 13 publications

Electron Transfer Kinetics at Interfaces Using SECM (Scanning Electrochemical Microscopy

Electron Transfer Kinetics at Interfaces Using SECM (Scanning Electrochemical Microscopy

Soft Stylus Probes for Scanning Electrochemical Microscopy

Improvement of Detectable Sensitivity for Enzyme Reaction by Scanning Electrochemical Microscopy with Distance Control System for Immunosensing

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