Nano Archive

Development of electrochemical calcium sensors by using silicon nanowires modified with phosphotyrosine

Bi, Xinyan and Wong, Wan Ling and Ji, Wenjun and Agarwal, Ajay and Balasubramanian, N and Yang, Kun-Lin (2008) Development of electrochemical calcium sensors by using silicon nanowires modified with phosphotyrosine. BIOSENSORS & BIOELECTRONICS, 23 (10). pp. 1442-1448.

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This paper reports the electrical detection of calcium ions by using silicon nanowires (SiNWs) as channels in a chemically gated field-effect-transistor (FET) configuration. To obtain a selective and sensitive layer for calcium sensing, the SiNWs are modified with a biologically relevant amino acid phosphotyrosine (p-Tyr), which is able to complex calcium ions with high affinity. It is found that when the p-Tyr modified SiNWs are exposed to aqueous solutions containing calcium ions, their conductances increase with the increasing of calcium concentration up to 10 mu M. In contrast, when the SiNWs are exposed to sodium or potassium, or when they are modified with tyrosine (Tyr), no significant increase in the conductance is observed. This finding suggests that the calcium ions complexed with the phosphate group of p-Tyr can act as a positive gate voltage on the FET device comprising of n-type SiNWs, and leads to an increase in their conductances. The FET device is also sensitive to magnesium ions. However, the response is 10 times lower than that of calcium at the same concentration. The study reported here may pave the way for designing an intracellular calcium sensor which permits the monitoring of calcium concentration in real time. (C) 2007 Elsevier B.V. All rights reserved.

Item Type:Article
Uncontrolled Keywords:electrochemical; silicon nanowire; phosphotyrosine; calcium sensors; field-effect-transistor
Subjects:Material Science > Functional and hybrid materials
Analytical Science > Nanotechnology for sensing and actuating
Material Science > Nanochemistry
Material Science > Nanostructured materials
ID Code:1235
Deposited By:Anuj Seth
Deposited On:16 Dec 2008 10:05
Last Modified:12 Feb 2009 14:08

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