Electrochemical Biosensors Were Constructed Based On Graphene And Its Complexes For The Detection Of Tumor Markers

The detection of tumor-related markers is of great significance to the effective diagnosis and treatment of diseases.The emergence of biosensors provides a new tool for the rapid,efficient and sensitive detection of these markers.In particular,the synthesis of new materials provides the basis for the development of biosensors.As an important member of the carbon nanomaterials,graphene(GR)has many excellent and unique properties,which has emerged to be an ideal material for the construction of biosensors.In this paper,graphene and its nanocomposites were prepared using graphite as the starting material.The obtained graphene nanomaterials were well characterized,which were further used to modify the electrode and construct electrochemical biosensors.The fabricated electrochemical biosensors achieved sensitive and selective detection of tumor markers.(1)An in situ growth protocol of 4-Aminothiophenol was introduced to fabricate three-dimensional graphene films(3D GFs)on gold substrates.The electrochemical performance of the electrode is improved remarkably in comparison with the conventional graphene modified eletrode.The 3D GF-modified electrode is successfully utilized as working electrode for electrochemical detection of nucleic acid(microRNA-155)and protein(lysozyme)based on a signal-on sensing mechanism with high sensitivity and selectivity.Furthermore,this biosensor is resistant to the interferences and proved successful towards the practical analysis.(2)The photoelectric biosensor was constructed by taking advantages of large area and high electrical conductivity of self-assembled GR and peroxidase-like activity of hemin.The self-assembly of GR was intiated by target DNA.The biosensor has achieved the detection of HBV-DNA with fast speed,high sensitivty,good selectivity and low cost.(3)The magnetic nanocomposites of 3D-GR/PdNPs/Fe3O4 with catalytic activity were synthesized by hydrothermal reduction method.The 3D-GR provides large area for the attachment of PdNPs,which effectively enhanced the catalytic activity of the nanocomposites.Moreover,the as-prepared materials are used to modify electrode through magnetic adsorption directly.Moreover,an electrochemical biosensor was constructed based on this modified electrode,which further applied to highly sensitive detection of Lyz.