A nanochannel array-based electrochemical device for quantitative label-free DNA analysis.
A strategy for label-free oligonucleotide (DNA) analysis has been proposed by measuring the DNA-morpholino hybridization hindered diffusion flux of probe ions Fe(CN)(6)(3-) through nanochannels of a porous anodic alumina (PAA) membrane. The flux of Fe(CN)(6)(3-) passing through the PAA nanochannels is recorded using an Au film electrochemical detector sputtered at the end of the nanochannels. Hybridization of the end-tethered morpholino in the nanochannel with DNA forms a negatively charged DNA-morpholino complex, which hinders the diffusion of Fe(CN)(6)(3-) through the nanochannels and results in a decreased flux. This flux is strongly dependent on ionic strength, nanochannel aperture, and target DNA concentration, which indicates a synergetic effect of steric and electrostatic repulsion effects in the confined nanochannels. Further comparison of the probe flux with different charge passing through the nanochannels confirms that the electrostatic effect between the probe ions and DNA dominates the hindered diffusion process. Under optimal conditions, the present nanochannel array-based DNA biosensor gives a detection limit of 0.1 nM.
Li
Su-Juan
SJ
Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Li
Jing
J
Wang
Kang
K
Wang
Chen
C
Xu
Jing-Juan
JJ
Chen
Hong-Yuan
HY
Xia
Xing-Hua
XH
Huo
Qun
Q
D000537:Aluminum Oxide / Q000737:chemistry; D001483:Base Sequence; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation*; D008567:Membranes, Artificial; D009025:Morpholines / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation*; D009994:Osmolar Concentration; D016062:Porosity; D055672:Static Electricity
D008567:Membranes, Artificial; D009025:Morpholines; C037574:morpholine; D004247:DNA; D000537:Aluminum Oxide