Sepiolite is a natural clay silicate that is widely used,
including
biomedical applications; notably sepiolite shows promising features
for the transfer of biological macromolecules into mammalian cells.
However, before its use, such an approach should address the efficiency
of binding to biological macromolecules and cell toxicity. Because
sepiolite spontaneously forms aggregates, its disaggregation can represent
an important challenge for improving the suspension performance and
the assembly with biological species. However, this can also influence
the toxicity of sepiolite in mammalian cells. Here, a very pure commercial
sepiolite (Pangel S9), which is present as a partially defibrillated
clay mineral, is used to study the consequences of additional deagglomeration/dispersion
through sonication. We analyzed the impact of extra sonication on
the dispersion of sepiolite aggregates. Factors such as sonication
time, sonicator power, and temperature are taken into account. With
increasing sonication time, a decrease in aggregation is observed,
as well as a decrease in the length of the nanofibers monitored by
atomic force microscopy. Changes in the temperature and pH of the
solution are also observed during the sonication process. Moreover,
although the adsorption capacity of bovine serum albumin (BSA) protein
on sepiolite is increased with sonication time, the DNA adsorption
efficiency remains unaffected. Finally, sonication of sepiolite decreases
the hemolytic activity in blood cells and the toxicity in two different
human cell lines. These data show that extra sonication of deagglomerated
sepiolite can further favor its interaction with some biomacromolecules
(e.g., BSA), and, in parallel, decrease sepiolite toxicity in mammalian
cells. Therefore, sonication represents an alluring procedure for
future biomedical applications of sepiolite, even when using commercial
defibrillated particles.