Recent progress of organic fluorescent molecules for bioimaging applications: cancer-relevant biomarkers

Currently, cancer threatens the quality of human life. There have been 44 drugs for various cancer diseases among 200 drugs which were top pharmaceuticals by retail sales around the world, suggesting their huge demand for human health. An effective and novel diagnosis method for cancerous diseases is urgently needed for planning and evaluating treatment procedures. Since the micro-environments of normal and cancer cells show different behaviors, they provide us with new possibilities for designing and developing suitable fluorescent probes relating to the behavior of cancer generation. The visualization of these cancer-relevant biomarkers is significantly meaningful to show the overall distribution of biomarkers at different distributions and depths in biological tissue, benefiting the quantitative estimation of biomarkers and accurate diagnosis of the related cancers at an early stage. Over the past six years, large amounts of fluorescent probes including organic compounds and nanomaterials for various cancer biomarkers have been extensively explored and designed for application to living systems. This review is devoted to fluorescence probes applied in the sensing and fluorescent imaging of four types of cancer-relevant biomarkers H+, NO, H2S and reactive oxygen species (H2O2, HClO, O2-, 1O2 and OH) over the past six years including recognition mechanism, reaction modes and corresponding applications. The work reports the progress of small-fluorescent molecules for bioimaging applications to cancer-relevant biomarkers H+, NO, H2S and reactive oxygen species (H2O2, HClO, O2-, 1O2 and OH) over the past six years.