Controllable n-Fe2O3@graphene nanomaterials by ALD applied in an aptasensor with enhanced electrochemical performance for thrombin detection

Abstract

An elegant atomic layer deposition (ALD) method has been employed for the controllable preparation of a uniform Fe₂O₃-coated graphene nanostructure (Fe₂O₃@graphene). The Fe₂O₃ coating thickness of the Fe₂O₃@graphene nanostructure can be tuned by varying the cycle number of Fe₂O₃ ALD. The produced Fe₂O₃@graphene composites are characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and cyclic voltammetry (CV). It is revealed that Fe₂O₃ is effectively deposited on the surface of graphene. Combined with the high affinity and specificity of an aptamer, a simple, rapid and sensitive electrochemical aptasensor was successfully fabricated for thrombin detection. The resulting electrochemical aptasensor displays a linear response to thrombin in the 1.0 × 10⁻¹¹ to 4.0 × 10⁻⁹ M concentration range with the detection limit of 1.0 × 10⁻¹² M (at an S/N of 3). The described controllable multifunctional graphene nanomaterials from ALD are expected to be applied in a biosensing platform which will exhibit wide applications in biological, medical, and environmental fields.