Label-free detection of protein-protein interactions using a calmodulin-modified nanowire transistor
Date Issued
2010
Date
2010
Author(s)
Hsieh, Po-Jen
Abstract
We demonstrate a highly sensitive, label-free, and reusable silicon nanowire field-effect transistor to detect protein-protein interactions. This reusable sensorial device was made possible by the reversible association-dissociation of glutathione S-transferase-tagged calmodulin with a glutathione modified nanowire transistor. The calmodulin-modified nanowire transistor showed an electrical response selectively to Ca2+ (1 uM) and a purified cardiac troponin I (~7 nM) with its conductance change having a linear dependence on the concentration of troponin I in the range between 10 nM and 1 uM, consistent with the previously reported concentration range where the dissociation constant for the troponin I-calmodulin complex was determined. The minimum concentration of Ca2+ required to activate the interaction between troponin I and calmodulin was determined around 1 uM. We have also successfully demonstrated that the N-type Ca2+ channels expressed in cultured 293T cells could be recognized specifically by the calmodulin-modified nanowire transistor. This highly sensitive and selective nanowire transistor can serve as a high-throughput biosensor to fast screen interacting proteins under physiological conditions.
Subjects
silicon nanowire field-effect transistor
protein-protein interaction
calcium ion
calmodulin
cardiac troponin I
N-type calcium channel.
Type
thesis
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