This review article by Parikha Mehrotra discusses the various types of biosensors and their applications across multiple fields. Biosensors are analytical devices that convert biological responses into electrical signals, and they are characterized by their high specificity, independence from physical parameters, and reusability. The article covers enzyme-based, tissue-based, immunosensors, DNA biosensors, thermal and piezoelectric biosensors, and fluorescent biosensors. Key applications of biosensors include: 1. **Food Industry**: Monitoring food quality and safety, detecting pathogens, and quantifying sweeteners. 2. **Fermentation Processes**: Controlling fermentation processes, monitoring glucose levels, and detecting by-products. 3. **Medical Field**: Diagnosing diseases such as diabetes, early detection of heart diseases, and rapid detection of human papilloma virus. 4. **Fluorescent Biosensors**: Used in drug discovery, cancer research, and early detection of biomarkers. 5. **Biodefense**: Identifying biological warfare agents in real-time. 6. **Metabolic Engineering**: Monitoring cellular metabolism and selecting desired phenotypes. 7. **Plant Biology**: Visualizing metabolic processes and identifying missing components in metabolism. The article also highlights the future scope of biosensors, including the use of nanomaterials to enhance their performance and the potential for single-molecule biosensors. The review emphasizes the importance of biosensors in various sectors and their role in advancing scientific research and technological development.This review article by Parikha Mehrotra discusses the various types of biosensors and their applications across multiple fields. Biosensors are analytical devices that convert biological responses into electrical signals, and they are characterized by their high specificity, independence from physical parameters, and reusability. The article covers enzyme-based, tissue-based, immunosensors, DNA biosensors, thermal and piezoelectric biosensors, and fluorescent biosensors. Key applications of biosensors include: 1. **Food Industry**: Monitoring food quality and safety, detecting pathogens, and quantifying sweeteners. 2. **Fermentation Processes**: Controlling fermentation processes, monitoring glucose levels, and detecting by-products. 3. **Medical Field**: Diagnosing diseases such as diabetes, early detection of heart diseases, and rapid detection of human papilloma virus. 4. **Fluorescent Biosensors**: Used in drug discovery, cancer research, and early detection of biomarkers. 5. **Biodefense**: Identifying biological warfare agents in real-time. 6. **Metabolic Engineering**: Monitoring cellular metabolism and selecting desired phenotypes. 7. **Plant Biology**: Visualizing metabolic processes and identifying missing components in metabolism. The article also highlights the future scope of biosensors, including the use of nanomaterials to enhance their performance and the potential for single-molecule biosensors. The review emphasizes the importance of biosensors in various sectors and their role in advancing scientific research and technological development.