Hierarchical 0D-2D bio-composite film based on enzyme-loaded polymeric nanoparticles decorating graphene nanosheets as a high-performance bio-sensing platform

Herein, we developed a hierarchical bio-composite sensing film by facile one-step electm-deposition of OD enzyme-polymer nanoparticles (NPs) with 2D graphene oxide nanosheets as conductive supports and nanofillers, based on which an effective and robust enzymatic biosensor platform was constructed. Horseradish peroxidase (HRP) as a model enzyme was co-assembled with a photo-cross-linkable polypeptide of 2-hydroxyethyl methacrylate modified poly(gamma-glutamic acid) (gamma-PGA-HEMA), generating hybrid HRP@gamma-PGA-HEMA nanoparticles (HRP@PGH NPs). Then HRP@PGH NPs and graphene oxide nanosheets (GO NSs) were simultaneously electrodeposited onto the electrode surface, obtaining a hierarchical OD-2D bio-composite film. After subsequent electrochemical reduction of GO NSs into graphene nanosheets (GNSs) and following photo-cross-linking, the resultant nanostructured HRP@PGH/GNSs sensing film was successfully applied to construct an enzymatic biosensor for hydrogen peroxide (H2O2). The biosensor exerted high sensitivity, fast response, and good stability for H2O2 sensing. Satisfactory results were also demonstrated for its practical application in human serum samples, suggesting a promising application potential in biomedical diagnostics. The one-step generated OD-2D bio-composite sensing film demonstrates synergetic effects from both the soft nanoparticles and hard conductive nanosheets, which would enlighten the innovative construction of composite nanomaterials and nano-architectonics for bio-sensing systems.