Protein Sensor Using Carbon Nanotube Field Effect Transistor

Abstract

The effect of the selective adsorption of pig serum albumin as an antigen on the electrical properties of a carbon nanotube channel field effect transistor on which anti-pig serum albumin was immobilized as an antibody by physisorption in phosphate buffer solution has been investigated. We have succeeded in real-time detection of the adsorption of pig serum albumin on anti-pig serum albumin as a decrease in the conductance of the carbon nanotube channel field effect transistor, by a label-free process.

Carbon nanotube biosensors: The critical role of the reference electrode

“…in V interface ͑Pt, solution͒ varies from about −20 to − 40 mV. Our measurements imply that the results from earlier CNT biomolecule-binding sensors which used bare wire to control the solution potential [3][4][5][6][7][8][9][10] are ambiguous. The interaction of protein with a Pt wire surface changes the electrostatic potential of the solution and can therefore cause changes in CNT conductivity.…”

“…1 The adsorption of biomolecules on the sidewall of a semiconducting carbon nanotube ͑CNT͒ or nanowire causes changes in local electrostatic environment, thereby changing the conductance of the nanomaterial. Pioneering work has indicated that this modulation of conductivity can be utilized to build CNT-based [2][3][4][5][6][7][8][9][10][11] and nanowire-based 1,12 sensors for real-time electrical detection of proteins or DNA. These sensors must be carefully designed to give reliable measurements of biomolecule binding.…”

“…The solution potential was not well controlled in many CNT biomolecule-binding experiments. [3][4][5][6][7][8][9][10] Reported conductance changes can have little or no relationship to interactions between biomolecules and the CNT transistor, leading to unreliable sensors and hindering efforts to determine sensing mechanisms. We show that a major biosensing artifact can be removed by using a well-defined reference electrode to accurately control the solution potential.…”

“…1͑a͒. [3][4][5][6][7][8][9][10] The device is exposed to solution, allowing protein adsorption on the semiconducting CNT. A metal wire is used to control the electrostatic potential of the solution.…”

Amperometric Enzyme-based Biosensors for Lowering the Interferences

“…Nevertheless, they miniature the size and have the properties of fast response, less sample and low cost (Auroux et al, 2002) and this kind of sensing chip is also called Lab-on-a-chip. For example, the biosensors based on the field effect transistor (FET) made by MEMS immobilize anti-PSA on the carbon nanotubes (CNTs) (Kojima et al, 2005), liquid-chromatography-based biochip detects peptide mixture (Xie et al, 2005), and the biochip combines PCR-based DNA amplification and electrochemical detection (Lee et al, 2003) have been reported. Other few examples include antibody-based chips for determining protein isoform (Loonberg & Carlsson, 2006), liquid-chromatography-based chips for detecting peptide mixture (Xie et al, 2005), and electrophoresis-based chips for sensing catechol and dopamine (Schoning et al, 2005).…”