Hollow BiOBr/reduced graphene oxide hybrids encapsulating hemoglobin for a mediator-free biosensor

For the construction of a mediator-free biosensor, hollow BiOBr microspheres (H-BiOBr MS) were hydrothermally synthesized and combined with reduced graphene oxide (H-BiOBr/rGO hybrids); then, the hybrids were applied to immobilize hemoglobin (Hb) on the surface of a glassy carbon electrode. The structure and morphology of the H-BiOBr MS and H-BiOBr/rGO hybrids were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electronic microscopy (TEM). The experimental results demonstrate that the hollow H-BiOBr/rGO hybrid material has a larger specific surface area and better biocompatibility, which is beneficial for immobilization of hemoglobin (Hb) and furthermore allows proteins to become more stable and bioactive. In addition, the as-prepared modified electrode hybrids can improve effectively the direct electron transfer of Hb. As a result, the hollow BiOBr/rGO microspheres-based H2O2 biosensors exhibit a wide linear range of 0.1 to 420 mu M and extremely low limit of detection 0.02 mu M. The drafted biosensor holds 93.7% of the preliminary feedback to H2O2 after 60-day storage. It is concluded that the mediator-free biosensors containing hollow BiOBr/rGO microspheres have wide applications in biomedicine and environmental analysis.

Automated summary

The research utilized hollow BiOBr microspheres (H-BiOBr MS) and H-BiOBr/rGO hybrids synthesized via hydrothermal method as materials for mediator-free biosensors to immobilize hemoglobin. The hybrids showed larger specific surface area and better biocompatibility, leading to more stable and bioactive proteins. The modified electrode hybrids effectively improved the direct electron transfer of hemoglobin, resulting in wide linear range and low limit of detection for H2O2 biosensors.