Playing with Emissions for Naked Eye Detection: Nanoparticl-Based Ratiometric Sensing

There is a crucial demand to develop a sensitive, fast, low-cost and portable strategy for the on-site detection in environments, medicines and foods, which has always been attracting considerable efforts in the construction of new chemical sensors1. With high sensitivity and simplification, fluorescence-based sensors are most widely studied due to a wide range of available fluorescent dyes and luminescent nanostructures including quantum dots (QDs), graphene oxide, and carbon dots (CDs)2-4. Instead, fluorescent sensors possess another unparalleled advantage, that is, their visualization capability for the determination of analytes with the naked eye by the aid of a simple ultraviolet (UV) lamp1.In general, a single-colorful fluorescent probe only can display the change of fluorescence brightness by either “turn on” or “turn off” with analytes, greatly limiting their quantitative capability1. An accurate/visual quantification mainly depends on the color variations (by the use of two or three fluorescent probes) rather than only brightness, because our eye is more sensitive to colors. However, the use of multicolorful fluorescent probes toward the wide color variations with target dosages remains a fascinating challenge for analytical chemists and still under investigation. In this presentation, the recent advances in design of color-multiplexing based fluorescent probes for detection and discrimination between different analytes are addressed, with focus on our own work2-5.