| Fluorescent labeling techniques have been widely used in cell imaging, protein detectionand DNA probing because it offers a highly sensitive visualization tool for detectingbiological macromolecules and monitoring biological events under real, living conditions.However, fluorescence quenching effect will occur when conventional luminescent materialsare used in high concentrations.;In contrast, we discovered the novel phenomenon of aggregation-induced emission (AIE):nonemissive dyes with propeller-shaped molecular structures such as silole, tetraarylethene,fulvene, pyran and polyaryl are induced to emit efficiently by aggregate formation. These intriguing properties of the AIE fluorogens prompted us to explore the possibility of utilizingthem as fluorescence biosensors.;Synthetized lipophilic silole derivatives can readily pass through cell membranes, stainonly the cell cytoplasm, and form highly emissive nanoaggregates in aqueous media withoutany obvious cytotoxicity against living cells. The compound molecules were found to beretained inside of the cells without noticeable leakage to the outside. Thus, these newAIE-based compounds can be used as selective and cell-compatible fluorescent dyes forlong-time living cell imaging.;Tetraphenylethane (TPE) fluorogens with amine-reactive functional group andthiol-reactive fuctional group were also synthesized and used to specifically label lysine (Lys)residues and cysteine (Cys) residues of proteins, respectively. Because of the AIEcharacteristics, the fluorescent detection of proteins through functionalized TPE fluorogensdoes not exhibit the fluorescence quenching effect which traditional fluorescent detectionmethods usually suffer from.;Fluorescent DNA segments are prepared by using silole labeled aminoallyl-dUTP throughenzymatic incorporation methods. Fluorescent products with extremely high degree oflabeling (DOL) can be obtained with no fluorescence quenching effect. The products can befurther used as fluorescent DNA probes in many bioapplications. |
