Early-Stage Development of Novel Cyclodextrin-siRNA Nanocomplexes Allows for Successful Postnebulization Transfection of Bronchial Epithelial Cells

Abstract Background: Successful delivery of small interfering RNA (siRNA) to the lungs remains hampered by poor intracellular delivery, vector-mediated cytotoxicity, and an inability to withstand nebulization. Recently, a novel cyclodextrin (CD), SC12CDClickpropylamine, consisting of distinct lipophilic and cationic subunits, has been shown to transfect a number of cell types. However, the suitability of this vector for pulmonary siRNA delivery has not been assessed to date. To address this, a series of high-content analysis (HCA) and postnebulization assays were devised to determine the potential for CD-siRNA delivery to the lungs. Methods: SC12CDClickpropylamine-siRNA mass ratios (MRs) were examined for size and zeta potential. In-depth analysis of nanocomplex uptake and toxicity in Calu-3 bronchial epithelial cells was examined using IN Cell® HCA assays. Nebulized SC12CDClickpropylamine nanocomplexes were assessed for volumetric median diameter (VMD) and fine particle fraction (FPF) and compared with s...