High-density attachment of FePt nanoparticles on carbon nanotubes by a facile microwave-assisted polyol method

One-pot synthesis of carbon-decorated FePt nanoparticles and their application for label-free electrochemical impedance sensing of DNA hybridization

“…The FePt-CNT and FePt-GO NPs were synthesized as in our previously reported route with a slight modification. 21 In a typical synthesis, GO or CNTs (20-30 mg) were completely dispersed into ethylenediamine (en) solvent or ethylene glycol (EG) solution with the assistance of sonication. After that, FeCl 2 ?4H 2 O (0.15 g, 0.75 mmol), H 2 PtCl 6 ?6H 2 O dispersed in ethylene glycol (EG) solution (36 mL, 9.65 6 10 -D6 mol mL 21 ) and NaOH (0.15 g, 3.125 mmol) were added into the aforementioned mixed solution under sonication.…”

“…21 In a typical synthesis, GO or CNTs (20-30 mg) were completely dispersed into ethylenediamine (en) solvent or ethylene glycol (EG) solution with the assistance of sonication. After that, FeCl 2 ?4H 2 O (0.15 g, 0.75 mmol), H 2 PtCl 6 ?6H 2 O dispersed in ethylene glycol (EG) solution (36 mL, 9.65 6 10 -D6 mol mL 21 ) and NaOH (0.15 g, 3.125 mmol) were added into the aforementioned mixed solution under sonication. The micro-wave-assisted reactions of the mixture are similar to those in our previous report.…”

“…Prior to modification, the GCE surface was freshly polished prior to each experiment with 0.3 mm and 0.05 mm a-Al 2 O 3 paste, respectively, and was rinsed with doubly distilled water after each polishing step, and finally cleaned ultrasonically in 95% ethanol and water, respectively, for 3 min. 10 mL of 2.0 mg mL 21 FePt-CNTs or FePt-GO suspension was placed on the electrode and allowed to dry at room temperature, and thus uniform membrane-coated electrodes (FePt-CNTs-GCE or FePt-GO-GCE) were obtained. Immobilization of ssDNA probes was performed by immersing the FePt-CNTs-GCE or FePt-GO-GCE in 2.0 mL PBS buffer solution (pH 7.0) containing 1.0 6 10 27 mol L 21 ssDNA probes for 2 h at room temperature, followed by washing the electrode with 0.5% sodium dodecylsulfate (SDS) solution and then rinsing it with doubly distilled water to remove the un-immobilized ssDNA.…”

“…Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements of 1.0 mmol L 21 K 3 Fe(CN) 6 and 1.0 mmol L 21 K 4 Fe(CN) 6 were performed on an EC500 electrochemical analyzer (Wuhan GaossUnion Company, China) with 0.1 mol L 21 KCl as the supporting electrolyte. The CV scan-rate was 100 mV s 21 . The AC voltage frequencies ranged from 10 kHz to 0.1 Hz.…”

“…The ssDNA-FePt-GO-GCE was also used for quantitative analysis of the PML-RARA fusion gene target sequence, as shown in Fig. 3B, and the detection range was from 1.0 6 10 213 to 1.0 6 10 27 mol L 21 with a detection limit of 3.5 6 10 214 mol L 21 . The detection limit for the present work (2.1 6 10 213 mol L 21 for FePt-CNTs-GCE and 3.5 6 10 214 mol L 21 for FePt-GO-GCE) is comparable with some other published works based on CNTs (2.5 6 10 212 mol L 21 ) 22 or GO (1.1 6 10 213 mol L 21 ) 23 modified sensor systems using EIS, indicating that although the preparation process is simple, the FePt-CNTs and FePt-GO membranes still keep relatively high sensitivity for the electrochemical detection of DNA hybridization.…”