Self-assembly, Cytocompatibility, and Interactions of Desmopressin with Sodium Polystyrene Sulfonate

Peptide-polymer systems hold strong potential for applications in nanotherapeutics. Desmopressin, a synthetic analogue of the antidiuretic hormone arginine vasopressin, may serve as a valuable case of study in this context since it is a first-line treatment for disorders affecting water homeostasis, including diabetes insipidus. It also has an established use as a hemostatic agent in von Willebrand disease, and recently, its repurposing has been suggested as a neoadjuvant in the treatment of certain types of cancer. Despite its well-documented clinical uses, studies on the supramolecular organization of desmopressin and its association with polymers remain scarce, limiting the therapeutic benefits of these nanostructured arrays. Here, we investigate the self-assembly of desmopressin and its association with sodium polystyrene sulphonate (NaPSS), a potassium-binding polymer used to treat hyperkalemia. Using structural techniques such as small-angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM), and atomic force microscopy combined with infrared nanospectroscopy (AFM-IR), we identified that desmopressin associates with NaPSS to form hybrid fibrillar nanoassemblies characterized by β-turn enriched domains and the appearance of β-sheet content.