Biofunctionalization of Multi-walled Carbon Nanotubes (MWNTs) for the Fabrication of Protein Nano Biosensors

The novel properties or the unusual combinations of properties possessed by nano-structured materials open several possibilities towards fabricating advanced nano biosensors with superior sensitivity and specificity. Single-walled carbon nantubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) exhibit unique properties such as chemical stability, good mechanical properties, outstanding charge-transport characteristics and high surface area that makes them ideal for the design of nanobio sensors for detecting subfemtogram quantities of target protein, DNA, and RNA. In this work, we demonstrate a route for the fabrication of a novel and sensitive protein biosensor using multi-walled carbon nanotubes (MWNTs). The nanotubes were surface modified with carboxylic group (COOH) by refluxing in concentrated nitric acid, and then non-covalently attached to surface of clean glassy carbon electrode (GCE) surface using N,N, dimethlyformaide (DMF) solvent. The MWNTs were biofunctionalized with anti- S-100 antibodies of Schwann nerve cells, hybridized with S-100 antigen, and detected with FITC labeled IgG, and visualized with confocal microscope. The surface characterization of the functionalized nanotubes was done by FTIR and SEM. The protein molecular hybridization on the electrode will be monitored electrically making it a electrochemical biosensor system. This methodology will be further extended to the fabrication DNA biosensors