Using a minimalist approach, an 11‐residue peptide (Peptide 1 ) tagged with rhodamine fluorophore was designed and synthesized for selective detection of cancer cells. Peptide 1 contains RGD and NGR motifs to bind, respectively, integrins and aminopeptidase CD13, which are over expressed in cancer cells. Surface tension measurements revealed that peptide 1 possess surface‐active property owing to the overall hydrophobicity and cationic nature of the peptide. Peptide 1 displays cancer cell‐selective binding at ≤5.0 µM concentrations, while peptide 2 (randomized sequence of 1 ) shows non‐selective binding to normal and cancer cells. Fluorescence microscopy and FACS analysis demonstrated the intracellular localization of peptide 1 in three different cancer cell lines, confirming the role of RGD and NGR motifs. Cytotoxicity assay exhibited the viability of normal and cancer cells up to 100 µM concentrations of peptide 1 . Steady‐state fluorescence measurements disclosed the preferential interactions of the peptide 1 with anionic POPC/POPG bilayers rather than with zwitterionic POPC lipid bilayers. Circular dichroism studies showed minimal changes in the secondary structure of peptide 1 upon binding with the anionic lipid bilayers. Peptide 1 is largely unordered, non‐toxic, and useful for identification of cancer cells. Peptide 1 provides a template for designing drug‐loaded peptides for targeted delivery into cancer cells.

中文翻译：

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设计和合成用于选择性检测癌细胞的新型肽。

使用极简方法，设计并合成了用罗丹明荧光团标记的11个残基的肽（肽1），用于选择性检测癌细胞。肽1含有RGD和NGR基序，分别结合在癌细胞中过度表达的整联蛋白和氨基肽酶CD13。表面张力测量结果表明，肽1具有由于总体疏水性和肽的阳离子性质的表面活性特性。肽1在≤5.0µM浓度下显示癌细胞选择性结合，而肽2（1的随机序列）显示与正常细胞和癌细胞的非选择性结合。荧光显微镜和FACS分析证明了肽1在三种不同癌细胞系中的细胞内定位，证实了RGD和NGR基序的作用。细胞毒性试验显示正常和癌细胞的活力高达100 µM肽1。稳态荧光测量揭示了肽1与阴离子POPC / POPG双层而不是两性离子POPC脂质双层的优先相互作用。圆二色性研究表明，与阴离子脂质双层结合后，肽1二级结构的变化很小。肽1基本上无序，无毒，可用于识别癌细胞。肽1提供了一个模板，用于设计可靶向递送至癌细胞的载药肽。