6533b7d6fe1ef96bd1267274

RESEARCH PRODUCT

Fluorescent Core/Shell Nanoparticles for Specific Cell‐Nucleus Staining

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description

The highly fluorescent perylene-3,4,9,10-tetracarboxdiimide (PDI) chromophore is a popular dye and pigment because of its excellent chemical, thermal, and photochemical stability. Due to these outstanding properties, there have been several successful applications of PDI chromophores in various fields. Water-soluble and fluorescent PDI dyes have been used in biological applications such as the in vitro staining of cells and proteins. The combination of water solubility and high fluorescence quantum yield still represents a challenging goal since PDI dyes have a strong tendency to form aggregates in aqueous solution even at very low concentrations. Water solubility and high fluorescence quantum yields of ionic PDIs were obtained by introducing positively or negatively charged substituents into the bay region of the chromophore. Although these ionic PDIs penetrate the cytoplasmic membrane of living cells, the synthesis of PDIs with specific binding properties to subcellular compartments has not yet been achieved. Recently, the preparation of core/shell nanoparticles with high structural perfection, water-solubility, and biocompatibility has been reported. However, the synthesis and biological characterization of fluorescent core/shell nanoparticles with specific biological applications have not been demonstrated. Herein we describe a novel water-soluble, negatively charged PDI derivative that specifically labels the cell nucleus by strong binding to positively charged nuclear proteins, thus allowing their application as a fluorescent dye in pathological and histochemical studies. The core/shell nanoparticle (Figure 1, P1) consists of a central PDI chromophore, a rigid first-generation polyphenylene dendrimer scaffold for suppressing aggregation of the central PDI chromophore in aqueous media and a polymer shell with multiple carboxylic acid groups for inducing water solubility and biological specificity. The synthetic strategy towards P1 is shown in Scheme 1, starting from the previously