Plasma-activated multi-walled carbon nanotube–polystyrene composite substrates for biosensing

7 páginas, 6 figuras, 2 tablas.-- PACS 87.80.-y Biophysical techniques (research methods) 52.77.Bn Etching and cleaning 85.35.Kt Nanotube devices 07.07.Mp Transducers 79.60.-i Photoemission and photoelectron spectra.Carbon nanotube–polymer composites have shown to be suitable materials for the fabrication of electrochemical transducers. The exposed surface of these materials is commonly passivated by a very thin layer of the polymer component that buries the conductive carbon particles. Working with multi-walled carbon nanotube–polystyrene (MWCNT–PS) composite structures, it was previously described how a simple low power oxygen plasma process produced an effective etching of the composite surface, thereby exposing the conductive surface of CNTs. This work shows how this plasma process not only gave rise to a suitable composite conductive surface for electrochemical sensing but simultaneously exposed and created a high density of oxygen-containing functional groups at both the CNT and the PS components, without affecting the material’s mechanical stability. These chemical groups could be effectively modified for the stable immobilization of biological receptors. A detailed chemical characterization of the plasma-activated composite surface was possible using x-ray photoelectron spectroscopy. The material reactivity towards the tethering of a protein was studied and protein–protein interactions were then evaluated on the modified composite transducers by scanning electron microscopy. Finally, an amperometric immunosensor approach for the detection of rabbit Immunoglobulin G target analyte was described and a minimum concentration of 3 ng ml−1 was easily measured.This work was supported by Consolider-Ingenio 2010 (project no. CSD2006-00012) and MICINN (project no. TEC2007- 68012-C03-01). CF-S and EM acknowledge the Ministerio de Educación y Ciencia for the financial support through the Programa Ramon y Cajal.Peer reviewe

Plasma-activated multi-walled carbon nanotube–polystyrene composite substrates for biosensing

7 páginas, 6 figuras, 2 tablas.-- PACS 87.80.-y Biophysical techniques (research methods) 52.77.Bn Etching and cleaning 85.35.Kt Nanotube devices 07.07.Mp Transducers 79.60.-i Photoemission and photoelectron spectra.Carbon nanotube–polymer composites have shown to be suitable materials for the fabrication of electrochemical transducers. The exposed surface of these materials is commonly passivated by a very thin layer of the polymer component that buries the conductive carbon particles. Working with multi-walled carbon nanotube–polystyrene (MWCNT–PS) composite structures, it was previously described how a simple low power oxygen plasma process produced an effective etching of the composite surface, thereby exposing the conductive surface of CNTs. This work shows how this plasma process not only gave rise to a suitable composite conductive surface for electrochemical sensing but simultaneously exposed and created a high density of oxygen-containing functional groups at both the CNT and the PS components, without affecting the material’s mechanical stability. These chemical groups could be effectively modified for the stable immobilization of biological receptors. A detailed chemical characterization of the plasma-activated composite surface was possible using x-ray photoelectron spectroscopy. The material reactivity towards the tethering of a protein was studied and protein–protein interactions were then evaluated on the modified composite transducers by scanning electron microscopy. Finally, an amperometric immunosensor approach for the detection of rabbit Immunoglobulin G target analyte was described and a minimum concentration of 3 ng ml−1 was easily measured.This work was supported by Consolider-Ingenio 2010 (project no. CSD2006-00012) and MICINN (project no. TEC2007- 68012-C03-01). CF-S and EM acknowledge the Ministerio de Educación y Ciencia for the financial support through the Programa Ramon y Cajal.Peer reviewe