Fluorescent Sensors

Researchers are in enthusiastic pursuit of fluorescent sensors due to their widespread applications in clinical diagnostics, environmental monitoring, etc. Driven by the increasing demand for simple fluorescent sensors with fast response, and high sensitivity and selectivity, over the past decade, there has been significant interest in developing polymeric materials that allow not only the detection of different targets but also their imaging within living cells. Advances in synthetic chemistry have enabled the preparation of polymeric materials with tunable optical properties, well-controlled architecture, and various functionalities. This, in combination with various emerging sensing mechanisms, has revolutionized the design and operation of fluorescent sensors. Conjugated polymers are one of the most widely used macromolecules for fluorescent sensors. The unique combination of their light harvesting and electron delocalizing properties is favorable for optical sensing with amplified signal output via electron and energy transfer mechanisms. Further conjugation of ionic functional groups to conjugated polymer backbones or side chains yields conjugated polyelectrolytes that combine the properties of organic semiconductors with the unique physicochemical behaviors of polyelectrolytes, which are ideal materials for sensing, imaging, and device applications. Conjugated polyelectrolytes can also be incorporated into higher architecture macromolecules, such as block copolymers, which provide the opportunity to study interesting fundamental questions. In addition, novel, nonconjugated fluorescent polymers with and without conventional chromophores have been developed, significantly enriching the family of fluorescent macromolecules available. The recent discovery of the photophysical phenomenon of aggregation-induced emission has provided a new strategy to design macromolecules with weak emission in solution but significantly enhanced fluorescence in the aggregated or solid state, thereby offering new opportunities for sensor design. This Special Issue of Macromolecular Rapid Communications highlights recent advances related to the synthesis, characterization, and applications of polymeric materials, especially conjugated polymers, for fluorescent sensor applications. This issue covers a wide range of topics spanning from fluorescent sensor development and sensing mechanisms to macromolecular probe design. The topics include polymeric nanoparticles for magnetic/fluorescence imaging, cell tracing, cell migration inhibition, and protein detection; conjugated polyelectrolytes for ion detection, in vitro and in vivo biomarker sensing and imaging; conjugated polymer- and oligomer-based monitoring of protein aggregation; and detection of metal ions, explosives, volatile organic compounds, and enzymes. It is our hope that these contributions will further stimulate those who are already active in the field while also providing an easy entry point for interested researchers not currently involved with the topic. We would like to express our sincere thanks to all the contributors and reviewers for their dedicated work and the editorial team at Wiley-VCH for their strong support. We hope you enjoy reading this Special Issue!