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

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.