en اپتیک پزشکی، میکروسکوپ نوری و بیوفوتونیک Medical Optics, Optical Microscope, Biophotonics پژوهشي Research <span style="font-size:11pt"><span new="" roman="" style="font-family:" times=""><span style="font-weight:bold"><span style="color:#000000"><span style="font-style:normal"><span style="white-space:normal"><span style="text-decoration:none">Efforts to understand genetic diseases and mutations in biological systems are the most important driver of research development in medical and biomolecular sciences. Rapid, sensitive, accurate, and cost-effective biomolecule analysis is particularly important in diagnosis and treatment. The discovery of graphene as a new nanomaterial with a carbon structure with a single atom thickness due to its unique electronic, mechanical, thermal, and optical properties has opened a new topic in research in various biomedical sciences and the production of biosensors for biomolecule analysis. In this research, a biosensor based on a graphene field-effect transistor (GFET) is used to detect DNA with optimal accuracy and sensitivity, which can be a basis for making DNA detection tools. In the studied structure, using non-equilibrium Green function equations and Poisson equation, we study the electron transfer in graphene field-effect transistors. Then, by examining the interaction between nucleotide bases (C, G, A, T) and O6-carboxymethylguanine related to the colorectal cancer DNA sequence to detection of mutation will be identified by GFET, and their binding energy determined.</span></span></span></span></span></span></span> Nano Biosensor, Graphene Field-Effect Transistors, Gene Mutation 201 210 http://ijop.ir/browse.php?a_code=A-10-71-2&slc_lang=en&sid=1 Nasrin Vahedi. G nasrin_v81@yahoo.com 10031947532846004680 10031947532846004680 No Faculty of Physics, University of Tabriz, Tabriz, Iran Asghar Asgari asgari@tabrizu.ac.ir 10031947532846004681 10031947532846004681 Yes Faculty of Physics, University of Tabriz, Tabriz, Iran & Photonics Devises Research Group, Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz, Iran & School of Electrical, Electronic, and Computer Engineering; The University of Western Australia, Crawley, WA 6009, Australia Gholamreza Dehghan dehghan2001d@yahoo.com 10031947532846004682 10031947532846004682 No Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran