A Label-Free Impedimetric DNA Sensor Based on a Nanoporous SnO2 Film: Fabrication and Detection Performance

Sensors

Minh Hai Le²  Carmen Jimenez²  Eric Chainet¹  Valerie Stambouli² 

[1] Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI), 1130 rue de la Piscine BP75, 38402 Saint Martin d’Hères Cedex, France; E-Mail:;Université Grenoble-Alpes, CNRS, Laboratoire des Matériaux et du Génie Physique (LMGP), MINATEC, 3 parvis Louis Néel, 38016 Grenoble Cedex 1, France; E-Mails:

关键词: biosensor;    DNA;    label free detection;    fluorescence;    impedance spectroscopy;    nanoporous SnO₂ films;   

DOI  :  10.3390/s150510686

来源: mdpi

【 摘 要 】

Nanoporous SnO₂ thin films were elaborated to serve as sensing electrodes for label-free DNA detection using electrochemical impedance spectroscopy (EIS). Films were deposited by an electrodeposition process (EDP). Then the non-Faradic EIS behaviour was thoroughly investigated during some different steps of functionalization up to DNA hybridization. The results have shown a systematic decrease of the impedance upon DNA hybridization. The impedance decrease is attributed to an enhanced penetration of ionic species within the film volume. Besides, the comparison of impedance variations upon DNA hybridization between the liquid and vapour phase processes for organosilane (APTES) grafting on the nanoporous SnO₂ films showed that vapour-phase method is more efficient. This is due to the fact that the vapour is more effective than the solution in penetrating the nanopores of the films. As a result, the DNA sensors built from vapour-treated silane layer exhibit a higher sensitivity than those produced from liquid-treated silane, in the range of tested target DNA concentration going to 10 nM. Finally, the impedance and fluorescence response signals strongly depend on the types of target DNA molecules, demonstrating a high selectivity of the process on nanoporous SnO₂ films.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.