This work focused on the synthesis, physicochemical characterization and biotechnological applications of new nanomaterials composed of sepiolite for gene transfer. Biohybrids were obtained of sepiolite nanofibers covered by nucleic acids (DNA and RNA molecules). They were characterized by novel techniques and procedures, identifying that the DNA gets adsorbed onto the surface of sepiolite nanofibers that were previously subjected to disaggregation procedures for a maximum fractionation. Such interaction is mediated by silanol groups evenly spaced on the outer surface of silicate particles, through electrostatic interactions, hydrogen bonds, cation bridges and Van der Waals forces. It was shown that sepiolite can be spontaneously internalized by eukaryotic cells in culture, and the mechanisms mediating such internalization were characterized, both endocytic and non-endocytic. Similarly, it was found that sepiolite nanofibers can be transferred between neighboring cells spontaneously, these particles displaying intrinsic fluorescence that facilitates its detection within the cell as gene transfer vector. The biohybrids were assayed with satisfactory results for the transfer of a plasmid DNA vector into cancer cell lines, and strategies were also established to significantly increase their transfection efficiency. These studies demonstrated for the first time the use of sepiolite nanofibers as a platform for transferring nucleic acids and potentially other types of molecules into mammalian cells, those molecules administered for functional or therapeutic purposes, among other applications. This work granted the Annual Award of the National Academy of Sciences of Cuba for the year 2016.

This work was supported by La Ligue Nationale Contre le Cancer, ANR (Agence Nationale de la recherche, ANR-14-CE10-0010-02), AFM-Téléthon and INCa (Institut National du Cancer, 2011-1-RT-01, 2011-1-PLBIO-09, 2013-1-PLBIO-14), the MINECO in Spain (projects MAT2012-31759 and MAT2015-71117-R), and the EU COST Action MP1202. Thanks are due to the French Embassy in Cuba and the Campus France for their contribution in partial financial support.