Spermine-induced hybridization and charge inversion at the diffuse layer of a DNA-FET.
Detection of DNA hybridization events by using field-effect transducers is limited by the electrolyte content of the medium. So far, DNA was thought to hybridize only in solutions with concentrated electrolytes. In these media, the interface between the transducer gate and the solution is reduced to a thin layer in close contact with the surface, and DNA is poorly detected. In the present work, this limitation is overcome by using spermine as screening polycation. Hybridization assays with polycation concentrations as low as 10 microM are reported. This ensures that hybridization takes place at the diffuse layer of the interface. The reported results suggest a charge-inversion mechanism induced by spermine. A target sequence is real-time label-free detected in the range from 10 to 500 nM.
Departamento de Micro- y Nanosistemas, Centro Nacional de Microelectrónica (CNM-IMB, CSIC), Campus UAB 08193 Bellaterra, Barcelona, Spain. roberto.delarica@gmail.com
Roberto
R
de la Rica
César
C
Fernández-Sánchez
Cecilia
C
Jiménez-Jorquera
Antonio
A
Baldi
D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004058:Diffusion; D009693:Nucleic Acid Hybridization; D013096:Spermine / Q000737:chemistry*
D013096:Spermine; D004247:DNA