Date on Master's Thesis/Doctoral Dissertation

8-2010

Document Type

Master's Thesis

Degree Name

M.S.

Department

Mechanical Engineering

Committee Chair

Panchapakesan, Balaji

Author's Keywords

Bionanotechnology; Circulating tumor cells; CNT transistors; Biosensors; Electronic detection of biomolecules

Subject

Nanotubes; Carbon; Biosensors; Biomolecules--Electric properties

Abstract

The application of carbon nanotubes (CNTs) has captivated the curiosity of today's experts due to the escalating potential in the field of electronic detection of biomolecules. Their extreme environmental sensitivity and small size make them ideal candidates for future biosensing technologies. Recent studies have shown that the binding of receptor proteins (biomolecules located at the membrane of cells) with their corresponding antibodies immobilized on a carbon nanotube surface causes changes in the electrical properties of carbon nanotubes and have been measured with a carbon nanotube field effect transistor (CNTFET). This specific molecular interaction and sensitivity is promising for the direct detection of live cells in blood. In this study, a biosensor was developed based on carbon nanotube thin film transistors for the purpose of electrically detecting breast cancer cells (MCF-7) in blood. The electrical response of specific and non-specific interactions between anchored antibodies onto the carbon nanotube film surface and breast cancer cells mixed with blood were monitored and recorded. The electrical measurements indicate that devices functionalized with specific antibodies (anti-IGF1R) experience large conductivity drops (~60 %). However for those device printed with non-specific antibodies (anti-IgG), small changes (~10 %) in conductivity are measured. It is postulated that the addition of increasing number of MCF-7cells mixed with blood on a CNT surface functionalized with specific antibodies (anti-IGF1R) acts as a chemical gate modulating the current flow. Biosensing mechanistic studies using a liquid gated CNTFET, confirmed that the specific antibody-receptor binding can be attributed to electrostatic gating effect by which cancer cells can be screened in blood.

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