Efficient One-Pot Synthesis of Mussel-Inspired Molecularly Imprinted Polymer Coated Graphene for Protein-Specific Recognition and Fast Separation

Molecular imprinting at nanomaterial surfaces has shown good prospects to extract templates easily and to achieve excellent performances such as large binding capacity and fast adsorption. In this work, we describe a one-step approach to synthesize a novel surface protein-imprinted nanomaterial employing graphene as the supporting substrate and dopamine as the polymerizing monomer. By simply immersing graphene oxide (GO) in a weak alkaline solution of dopamine (DA) containing bovine hemoglobin (BHb), GO nanosheet was readily converted to reduced GO (RGO) by dopamine with simultaneous capping by a thin polydopamine film imprinted with BHb leading to the BHb imprinted PDA@RGO nanomaterials. Fourier transform infrared (FT-IR), ultraviolet-visible (UV-vis), Raman spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption experiments have been. used to characterize the resulting imprinted PDA@RGO. The whole reaction process was conducted in aqueous solution at ambient temperature, which is easy to scale up at a low cost without pollution. In addition, because of the unique properties of graphene (large surface area, high surface-to-volume ratio) and polydopamine (high biocompatibility and controllable thickness), the prepared imprinted PDA@RGO not only possessed high binding capacity (198 mg/g) but also exhibited a fast adsorption kinetics (adsorb 89% of the maximum amount within 5 min) and good selectivity toward template protein (the imprinting factor alpha is 4.95). The outstanding recognizing behavior coupled to the low production cost and facile, quick, green preparation procedure makes the imprinted PDA@RGO attractive in specific protein recognition and separation, biosensors, and biochips.