A highly thermostable peptoid cyclo-octamer can reversibly accommodate and release water molecules from central channels formed by the macrocycles in a crystalline array. We report the first single-crystal-to-single-crystal transformation for a peptidomimetic oligomer.

No abstract

The fluorophore rhodamine B is often used in biological assays. It is inexpensive, robust under a variety of reaction conditions, can be covalently linked to bioactive molecules, and has suitable spectral properties in terms of absorption and fluorescence wavelength. Nonetheless, there are some drawbacks: it can readily form a spirolactam compound, which is nonfluorescent, and therefore may not be the dye of choice for all fluorescence microscopy applications. Herein this spirolactam formation was observed by purifying such a labeled peptoid with high performance liquid chromatography (HPLC) and monitored in detail by making a series of analytical HPLC runs over time. Additionally, a small library of eight peptoids with rhodamine B as label was synthesized. Analysis of the absorption properties of these molecules demonstrated that the problem of fluorescence loss can be overcome by coupling secondary amines with rhodamine B.

Cell-penetrating peptoids are an important class of peptidomimetics, which can replace highly biodegradable cell penetrating peptides for enhanced drug delivery. Typically, they contain positively charged amino side chains which are synthesized via their protected analogues. To avoid the use of amine protecting groups a Click-chemistry based modular synthesis of novel hydrophilic as well as amphiphilic cell penetrating peptoids was developed to generate novel structures for drug delivery in cells.