Cytocompatibility and cellular uptake of alkylsilane-modified hydrophobic halloysite nanotubes

The extensive increase of application of surface-modified halloysite nanotubes in industry and biomedicine suggests that their biocompatibility and cellular uptake should be thoroughly investigated. Here we report the fabrication and cytocompatibility study of hydrophobic halloysite nanotubes coated with octadecyltrimethoxysilane (ODTMS). The interaction of ODTMS-modified halloysite nanotubes with human lung carcinoma alveolar epithelial cell A549 was investigated using dark field and atomic force microscopies, colorimetric viability tests and flow cytometry. Halloysite with different degrees of hydrophobicity penetrates into the human lung cells without membrane damage promising for efficient drug delivery. This formulation did not have an apoptosis-inducing effect on the cells, did not increase the activity of NO-synthase and can be employed for intracellular delivery of drugs, proteins and DNA without any toxic side effects.