Highly Emissive Pyrene-based Fluorophores and Highly Sensitive Fluorescent Sensors Using Pyrene Emission Switching

In this review, I report highly emissive pyrene-based fluorophores and highly sensitive fluorescent sensors using pyrene emission switching. Alkynylpyrene derivatives show fruitful photophysical properties, as compared with pyrene itself: longer absorption and emission wavelengths and high fluorescence quantum yields in the presence of O-2. Alkynylpyrene-based fluorescent probes allow the highly sensitive detection of biomolecules such as proteins. Additionally, a rotaxane-based fluorophore, consisting of an alkynylpyrene derivative and two cyclodextrins, is highly stable upon irradiation with a UV/vis illuminator. On the other hand, I and my colleagues have developed a variety of fluorescent sensors using pyrene emission switching. One of them is DNA probes in which two pyrenes are connected both at 3' and 5' ends of a single-stranded oligonucleotide. Emission switching occurs from excimer to monomer when the probes hybridized with target DNAs. The DNA probes met antibody structures to produce the following fluorescent sensors. The sensors consist of three functional regions, crown ether (or cyclodextrin), DNA, and pyrene as guest-binding, dimerizing, and sensing sites, respectively. These sensors can detect potassium cation, porphyrin, unsaturated fatty acid by pyrene monomer-excimer switching.