To improve the cellular uptake of tricyclo-DNA (tc-DNA), an oligonucleotide analog with promising activity in antisense and siRNA-based therapies, a palmityl ester was appended to the structure of tc-DNA.
It was shown that this lipophilic derivative helped the cellular uptake properties of a fluorescein-labeled oligonucleotide in two human cell lines without the use of a transfection agent, whereas oligonucleotides containing tc-DNA without modification were not internalized.

This work was carried out by Jory Liétard in the group of Prof. Christian Leumann.

References:

• J. Lietard, C. J. Leumann;
  "Synthesis, Pairing, and Cellular Uptake Properties of C(6')-Functionalized Tricyclo-DNA"
  J. Org. Chem., 77, 4566-4577, (2012); doi:10.1021/jo300648u.