Sonochemical fabrication of Fe3O4 nanoparticles on reduced graphene oxide for biosensors

This study synthesized Fe3O4 nanoparticles of 30–40 nm by a sonochemical method, and these particles were uniformly dispersed on the reduced graphene oxide sheets (Fe3O4/RGO). The superparamagnetic property of Fe3O4/RGO was evidenced from a saturated magnetization of 30 emu/g tested by a sample-vibrating magnetometer. Based on the testing results, we proposed a mechanism of ultrasonic waves to explain the formation and dispersion of Fe3O4 nanoparticles on RGO. A biosensor was fabricated by modifying a glassy carbon electrode with the combination of Fe3O4/RGO and hemoglobin. The biosensor showed an excellent electrocatalytic reduction toward H2O2 at a wide, linear range from 4 × 10−6 to 1 × 10−3 M (R2 = 0.994) as examined by amperometry, and with a detection limit of 2 × 10−6 M. The high performance of H2O2 detection is attributed to the synergistic effect of the combination of Fe3O4 nanoparticles and RGO, promoting the electron transfer between the peroxide and electrode surface.

► Fe3O4 nanoparticles are fabricated uniformly on the surface of reduced graphene oxide by a sonochemical method. ► The particle size of Fe3O4 are controlled at around 30–40 nm. ► The resultant Fe3O4/RGO composite shows a high biosensor performance. ► RGO promotes the electron transfer between the peroxide and electrode surface.