Transfecting nucleic acids into various cells is a key procedure in biological research also envisioned for therapeutic applications. In our effort to obtain simple reagents that would be readily accessible from commercial building blocks, we recently reported peptide dendrimers as single component siRNA transfection reagents accessible in pure form by solid-phase peptide synthesis. Here, we extend our studies of these dendrimers by identifying analogs bearing a coumarin or BODIPY fluorescent label in their core and displaying comparable siRNA transfection efficiencies, pH dependent aggregation, siRNA binding, and secondary structures. Fluorescence resonance energy transfer (FRET) studies show that the dendrimers are tightly associated with siRNA within the formed nanoparticles at pH 7.4 but are released into solution at pH 5.0 and can participate in endosome escape by destabilizing the membrane at this pH value. Colocalization studies furthermore suggest that peptide dendrimers and siRNA remain tightly associated throughout the transfection process.

中文翻译：

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用于siRNA转染的荧光肽树状聚合物：跟踪pH响应聚集，siRNA结合和细胞渗透。

将核酸转染到各种细胞中是生物学研究中的一个关键步骤，该过程也被设想用于治疗应用。为了努力获得可从商业构件轻松获得的简单试剂，我们最近报道了肽树状聚合物作为单组分siRNA转染试剂，可通过固相肽合成以纯净形式获得。在这里，我们通过鉴定在其核心中带有香豆素或BODIPY荧光标记的类似物并显示出可比的siRNA转染效率，pH依赖性聚集，siRNA结合和二级结构来扩展对这些树状聚合物的研究。荧光共振能量转移（FRET）研究表明，树状大分子在pH 7.4时与形成的纳米颗粒中的siRNA紧密相关，但在pH 5时释放到溶液中。0，并且可以通过在此pH值下使膜不稳定来参与内体逃逸。共定位研究进一步表明，肽树状大分子和siRNA在整个转染过程中仍然紧密相关。