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Phenylboronic acid monolayer-modified electrodes sensitive to sugars
Shigehiro Takahashi1, Jun-ichi Anzai
1Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Langmuir : the ACS Journal of Surfaces and Colloids
|May 18, 2005
Summary
New gold electrodes modified with MPBA and DTBA-PBA are sensitive to sugars. These electrodes detect sugars by monitoring changes in electrochemical signals, enabling quantitative analysis of common sugars like glucose and fructose.
Area of Science:
- Electrochemistry
- Materials Science
- Biosensors
Background:
- Gold electrodes are modified with 4-mercaptophenylboronic acid (MPBA) and dithiobis(4-butyrylamino-m-phenylboronic acid) (DTBA-PBA) to create sugar-sensitive surfaces.
- These modified surfaces form stable, well-packed monomolecular layers via sulfur-gold bonds.
Purpose of the Study:
- To develop novel sugar-sensitive electrodes using MPBA and DTBA-PBA modified gold surfaces.
- To investigate the electrochemical behavior of these modified electrodes in response to pH and sugar presence.
- To establish a method for quantitative sugar determination based on electrochemical signal changes.
Main Methods:
- Electrode modification with MPBA and DTBA-PBA.
- Cyclic voltammetry (CV) using Fe(CN)(6)(3-)(/4-) as a redox probe.
- pH-dependent electrochemical measurements to determine pK(a) values.
- Sugar-induced changes in electrochemical signals (peak current, i(p)) were analyzed.
Main Results:
- MPBA and DTBA-PBA modified electrodes showed pH-dependent blocking of Fe(CN)(6)(3-)(/4-) access, with estimated pK(a) values of 9.2 and 8.0, respectively.
- In the presence of sugars, the pK(a) values decreased to 8.3 and 7.2 (for MPBA and DTBA-PBA, respectively) due to phenylboronate ester formation.
- Calibration curves for determining 1-100 mM D-glucose, D-mannose, and D-fructose were successfully obtained.
Conclusions:
- MPBA and DTBA-PBA modified gold electrodes exhibit sugar sensitivity.
- The electrochemical response of these electrodes can be utilized for the quantitative determination of various sugars.
- This approach offers a promising method for sugar sensing applications.