Recent progress in fluorescent and colorimetric sensors for the detection of ions and biomolecules

Optical sensors are widely used in the field of analytical sensing and optical imaging because of their high sensitivity, fast response time, and technical simplicity. The advantages of sensors lay in their non-invasive approach within biological tissues and inherent reliability in fluorescence imaging tests. In recent years the development of optical sensors for the sensing of ions, neutral molecules and especially tumor micro-environment-related parameters has been an active research area. This review focuses on recent contributions concerning fluorescent or colorimetric sensors and is organized according to their target classifications.