Interdisciplinary alliances are extremely important for developing a safe and green environment as well as overcoming health and environmental challenges in the contemporary world. Recently nanotechnological principles are used in the rational design of nanoscale devices called nano sensors that measure physical quantities and convert these signals that can be detected and evaluated. Nano sensors thus enable the rapid detection of pathogens and pollutants and thus have application in health care sectors as well. Nano sensors can be prepared through various approaches like top-down lithography and bottom-up self-assembly supramolecular synthesis. Due to their sensitivity to pollutants nano sensors have found applications in food and environment sectors in analyzing pollutants and harmful metal ions. Nano sensors have also found crucial applications in medical fields and they include early detection of important diseases like cancer, infectious diseases caused by microorganisms and monitoring organ health post implementation. Other applications of nano sensors are molecular imprinting, selective detection of immune proteins, advances in diagnosis of pathogen like viruses etc. However, there are challenges like cytotoxic effects of nano sensors; technical challenges like precision in manufacturing, high cost of raw materials such as silicon, nanowires and nanotubes etc. With its application in many of the challenges associated with the environmental and health care sectors, nano sensors are an attractive area to both scientific and commercial world.