ABSTRACT:Recent advances in interdisciplinary research in molecular diagnostics have a quickly development of different classes of biosensors with increasingly better sensor characteristics. In addition, the development in engineering and nanotechnology areas has been of fundamental importance for miniaturization and technological multifunctionality of biosensors. Molecular diagnosis facilitates the primary detection of diseases with greater specificity and sensitivity, but they require time and are costly. Biosensors have emerged as a cheap, easy-to-handle, portable alternative with high sensitivity and specificity. Graphene is a two-dimensional nanomaterial with a thick carbon atom, the carbon atoms has sp2 hybridized and packaged in a crystalline lattice. Recently graphene has received special attention as an emerging material because of the potential applications due to their electrical, mechanical, optical and biological properties. Cancer is a public health problem, especially among developing countries, where it is expected that in the coming decades, the impact of cancer on the population will account for 80% of the estimated 20 million new cases by 2025. The estimate for Brazil, biennium 2016-2017, indicates the occurrence of about 600 thousand new cases of cancer. The graphene decorated with Au and Ag nanoparticles has been explored because of the Raman enhanced signal of the adsorbates exploiting a Surface Enhanced Raman Scattering (SERS) regime. To obtain the hybrid nanostructured substrates, the following techniques will be applied: 1) deposition of single graphene monolayer by chemical vapor deposition (CVD) and then coupling it to a metallic nanoparticle-based substrate and 2) by synthesizing 3D structures by hydrothermal synthesis composed by graphene and metallic nanoparticles. The higher quality SERS substrates will be used, after the characterization of composing materials, to detect small amounts (closed to single molecule regime) of cancer biomarkers. Compared with SERS substrates, which only contain metal NPs, the additional graphene layer provides structural, chemical, and optical advantages.
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