A simple fluorescent probe based on an ortho-hydroxy aldehyde-functionalized coumarin showed selective responses to homocysteine and cysteine by fluorescence turn-on.

The need to decipher various biological events has led to the elucidation of the molecular mechanisms underlying a number of disease processes. Consequently, the detection and simultaneous monitoring of chemical interactions between biological targets has become indispensable in medical diagnosis, targeted therapeutics, and molecular biology. Multiplexed applications employing nanomaterials, which represent the integration of nanotechnology and biology, have changed the bioanalytical outlook and provided various promising tools. Among these nanomaterials, fluorescent dye-doped silica nanoparticles have demonstrated excellent potential for use in advanced bioanalysis to facilitate deeper understanding of biology and medicine at the molecular level. In particular, silica nanoparticles have been applied to diagnostics and therapeutic applications in cancer and gene/drug delivery. This feature article summarizes recent developments in the synthesis, biocompatibility, and bioapplications of fluorescent dye-doped silica nanoparticles.

We have successfully developed a fluoride ion probe for fluorescence cell bioimaging—desirable properties include retention of the fluorophore inside cells, non-cytotoxicity to mammalian cells, appreciable solubility in water, and stoichiometric reaction with analytes.