This review discusses the application of graphene-based sensors for biological and chemical detection. Graphene, a single-layer carbon material with exceptional electrical, chemical, optical, mechanical, and structural properties, has shown great potential in sensor development. The review critically examines various types of graphene-based sensors, including electrochemical, electronic, optical, and nanopore sensors, and highlights their underlying detection mechanisms and unique advantages. It also discusses the properties and preparation methods of different graphene materials, their functionalization, and the challenges and perspectives of graphene sensors. Graphene can be synthesized through various methods, including mechanical exfoliation, chemical vapor deposition (CVD), and chemical reduction of graphene oxide (GO). Different graphene materials, such as single-layer graphene (SLG), reduced graphene oxide (RGO), and GO, have distinct properties and applications. For instance, RGO is more electrochemically active than pristine graphene due to its abundant reactive sites, making it suitable for electrochemical sensors. GO, on the other hand, is a non-conductive, atomically thin sheet with nano-sized sp² carbon clusters, and it can serve as a sensing element itself due to its optical properties. Graphene functionalization is crucial for enhancing its sensing capabilities. Covalent and noncovalent methods are used to modify graphene, enabling it to interact with detection targets and facilitate signal transduction. Covalent functionalization introduces chemical groups that can be used for surface modifications, while noncovalent methods rely on physical adsorption and interactions such as π-π stacking. The review highlights various applications of graphene-based sensors, including the detection of hydrogen peroxide, glucose, nucleic acids, proteins, and other biomolecules. For example, RGO-based sensors have been used to detect hydrogen peroxide with high sensitivity and a wide linear range. Electrochemical sensors based on RGO have also been developed for the detection of glucose, with low detection limits and high sensitivity. Additionally, graphene-based sensors have been used for the detection of nucleic acids, with high sensitivity and selectivity. The review also discusses the detection of other chemicals, such as environmental contaminants, pharmaceutical compounds, industrial compounds, and explosives. Graphene-based sensors have shown promising results in detecting these substances due to their high sensitivity and selectivity. In conclusion, graphene-based sensors offer a wide range of applications in biological and chemical detection, with their unique properties and tunable characteristics making them highly suitable for various sensing purposes. The review provides a comprehensive overview of the current state of graphene-based sensors and highlights their potential for future developments in this field.This review discusses the application of graphene-based sensors for biological and chemical detection. Graphene, a single-layer carbon material with exceptional electrical, chemical, optical, mechanical, and structural properties, has shown great potential in sensor development. The review critically examines various types of graphene-based sensors, including electrochemical, electronic, optical, and nanopore sensors, and highlights their underlying detection mechanisms and unique advantages. It also discusses the properties and preparation methods of different graphene materials, their functionalization, and the challenges and perspectives of graphene sensors. Graphene can be synthesized through various methods, including mechanical exfoliation, chemical vapor deposition (CVD), and chemical reduction of graphene oxide (GO). Different graphene materials, such as single-layer graphene (SLG), reduced graphene oxide (RGO), and GO, have distinct properties and applications. For instance, RGO is more electrochemically active than pristine graphene due to its abundant reactive sites, making it suitable for electrochemical sensors. GO, on the other hand, is a non-conductive, atomically thin sheet with nano-sized sp² carbon clusters, and it can serve as a sensing element itself due to its optical properties. Graphene functionalization is crucial for enhancing its sensing capabilities. Covalent and noncovalent methods are used to modify graphene, enabling it to interact with detection targets and facilitate signal transduction. Covalent functionalization introduces chemical groups that can be used for surface modifications, while noncovalent methods rely on physical adsorption and interactions such as π-π stacking. The review highlights various applications of graphene-based sensors, including the detection of hydrogen peroxide, glucose, nucleic acids, proteins, and other biomolecules. For example, RGO-based sensors have been used to detect hydrogen peroxide with high sensitivity and a wide linear range. Electrochemical sensors based on RGO have also been developed for the detection of glucose, with low detection limits and high sensitivity. Additionally, graphene-based sensors have been used for the detection of nucleic acids, with high sensitivity and selectivity. The review also discusses the detection of other chemicals, such as environmental contaminants, pharmaceutical compounds, industrial compounds, and explosives. Graphene-based sensors have shown promising results in detecting these substances due to their high sensitivity and selectivity. In conclusion, graphene-based sensors offer a wide range of applications in biological and chemical detection, with their unique properties and tunable characteristics making them highly suitable for various sensing purposes. The review provides a comprehensive overview of the current state of graphene-based sensors and highlights their potential for future developments in this field.