COLL 530 |
| Xin Yu1, Maire O’Connor2, Sang Nyon Kim3, Fotios Papadimitrakopoulos4, and James F. Rusling1. (1) Department of Chemistry, University of Connecticut, U-60, 55 N. Eagleville Rd., Storrs, CT 06269-3060, (2) Department of Chemistry, Dublin City University, Dublin, Ireland, (3) Institute of Materials Science, Polymer Program, University Of Connecticut, 97 North Eagleville Road, U-136, Storrs, CT 06269, (4) Nanomaterials Optoelectronics Laboratory, Department of Chemistry, Polymer Program, Institute of Materials Science, University of Connecticut, 97 North Eaglville Rd, U-3136, Storrs, CT 06269 |
| Single walled carbon nanotubes (SWNT) with high conductivities per unit cross-section and large surface areas offer the promise of fabricating ultra-sensitive biosensors and immunosensors. Oriented SWNT forests offer potential of being fabricated as ultramicroelectrodes and used for multielement nano-biosensor and nano-sensor arrays. We demonstrated in previous work that biosensors with enzymes covalently attached onto the ends of vertically oriented SWNT forest arrays have good sensitivity and detection limit towards detection of H2O2. In this paper, we report that improved fabrication and design leads to improved sensitivity with detection limits in the low nanomolar range. Also reported is a novel strategy of preparing immunosensors based on SWNT forest, the strategy was based on immobilization of antibody (anti-biotin, anti-mouse IgG, anti-HSA) on the carboxylated ends of the nanotube forests by amide linkages and direct electrochemistry of horseradish peroxidase that was labeled to the antigen or another antibody. Amperometry was employed to detect the amount of antigen by competitive and sandwich assays. This immunosensor had a detection limit for antigen in the picomol/ml range. Effect of different blocking agents (BSA , Casein, Tween-20) on removing non-specific binding was tested, with average non-specific binding below 5%.
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Symposium in Memory of Arthur W. Adamson
2:00 PM-4:40 PM, Thursday, April 1, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |