Electrochemical DNA biosensor based on IL-modified MWNTs electrode prepared by radiation-induced graft polymerization

作者：Chung D J; Whittaker A K; Choi S H^*

来源：Journal of Applied Polymer Science, 2012, 126(SUPPL. 2).

DOI：10.1002/app.36665

• E-DNA biosensor
• hybridization
• radiation-induced graft polymerization
• Salmonella typhi

Electrochemical DNA (E-DNA) biosensors were fabricated by the physical immobilization of probe DNA, 5';-GGA GCT GCT GGC ATT ATT GAA-3';, on ionic-liquid-multiwalled carbon nanotubes (IL-MWNTs) modified with indium tin oxide (ITO) electrodes to detect Salmonella typhi (S. typhi). IL-MWNTs were prepared by the introduction of 1-butylimidazole bromide onto an epoxy group on poly(GMA)-grafted MWNTs, which were synthesized by radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto MWNTs in aqueous solution. Subsequently, IL-MWNTs were coated onto the ITO electrode surface, and then the physical immobilization of the probe DNA performed in probe DNA solution at room temperature for 1 h. The IL-MWNTs were characterized by elemental analysis, XPS, and TGA. The electron transfer resistance (R et) of the E-DNA biosensor was evaluated after hybridization of the probe DNA and target DNA using electrochemical impedance spectroscopy. The R et increased after the hybridization of probe DNA and target DNA. The DNA used was complementary DNA: 5';-TTC AAT AAT GCC AGC AGC TCC-3';, single-base mismatch DNA: 5';-TTC AAT AAT GGC AGC AGC TCC-3'; and three-base mismatch DNA: 5';-TTC ATT AAT GGC AGC ACG TCC-3';. The dynamic detection range for the sequence-specific DNA of target DNA was from 1.0 × 10 -13 to 1.0 × 10 -10 mol L -1 with a regression equation R et (ω) = 18.6 C + 128 and regression coefficient (γ) of 0.996. The detection limit was determined to be 3.1 × 10 -14 mol L -1. The results demonstrated that the sensitivity of this impedance-based DNA sensor was sufficient for the target DNA sequence detection.

• 单位
  The university of Queensland