Selective nuclear localization of siRNA by metallic versus semiconducting single wall carbon nanotubes in keratinocytes

Abstract

Background: The potential use of carbon nanotubes (CNTs) in gene therapy as delivery systems for nucleic acids has been recently recognized. Here, we describe that metallic versus semiconducting single-wall CNTs can produce significant differences in transfection rate and cellular distribution of siRNA in murine PAM212 keratinocytes. Results/Methodology: The results of cell interaction studies, coupled with supportive computational simulations and ultrastructural studies revealed that the use of metallic single wall CNTs resulted in siRNA delivery into both the cytoplasm and nucleus of keratinocytes, whereas semiconducting CNTs resulted in delivery only to the cytoplasm. Conclusion: Using enriched fractions of metallic or semiconducting CNTs for siRNA complex preparation may provide specific subcellular targeting advantages.

Carbon nanotubes are a novel class of nanobuilding blocks extensively investigated as delivery systems for therapeutic RNAi to silence gene expression in the cell cytoplasm and nucleus. It was previously shown that the delivery properties of single wall carbon nanotubes (SWNTs) are influenced by their varied physicochemical characteristics, however, the effect of chirality and electronic properties of SWNTs have not been studied with respect to their role in cellular transfection. To the best of our knowledge, this is the first study that shows using metallic or semiconducting SWNTs for siRNA complex preparation may provide specific subcellular targeting advantages.

Keywords::

• chirality
• drug delivery
• keratinocytes
• metallic nanotubes
• semiconducting nanotubes
• single wall carbon nanotubes
• siRNA transfection

Acknowledgements

The authors thank M Collins at the Department of Mechanical and Mechatronics Engineering, University of Waterloo for his assistance with UV-Vis-NIR Spectrophotometer measurements. They also thank and acknowledge the assistance of M Parsons at the Flow Cytometry Core Facilities, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, for processing the imaging flow cytometry samples.

Financial & competing interests disclosure

This manuscript was supported by grants from the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council of Canada (NSERC). The generous support of the Canada Research Chairs Program, the Canada Foundation for Innovation and the Ontario Research Fund is also gratefully acknowledged. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This manuscript was supported by grants from the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council of Canada (NSERC). The generous support of the Canada Research Chairs Program, the Canada Foundation for Innovation and the Ontario Research Fund is also gratefully acknowledged. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.