Highly sensitive and renewable amperometric urea sensor based on self-assembled monolayer using porous silicon substrate

作者：Yun DH^*; Song MJ; Hong SI; Kang MS; Min NK

来源：Journal of the Korean Physical Society, 2005, 47: S445-S449.

• amperometric urea sensor
• self-assembled monolayer
• porous silicon

An amperometric urea sensor is more suitable than an optical and potentiometric urea sensor to diagnose hyperammonemia. However, because sensitivity at low concentration decreases remarkably, although the amperometric urea sensor has been studied for a long time, it has not been applied for clinical diagnosis. In this paper, a new structure for an amperometric urea sensor is fabricatcd by electrochemical etching techniques. As sensor, three thin-film electrodes are patterned on porous silicon (PS) substrate by using platinum RF sputtering, gold and silver evaporation. The attachment of urease (Urs) to a carboxylic-terminated self-assembled monolayer (SAM) chemisorbed onto gold electrode was achieved by using carbodiimide coupling. The formation of a self-assembled chemisorbed layer of urease on gold has been studied by X-ray photoelectron spectroscopy (XPS). Their electrochemical properties are characterized by the amperometry method. Measured sensitivity of the Urs/SAM/Au/PS electrode is ca.. 11.21 mu A/mMcm(2) and that of the Urs/SAM/Au/Planar Si electrode is ca. 4.39 mu A/mMcm(2). An about three-fold sensitivity increase is observed with the porous-silicon-based electrode.

• 出版日期2005-11