Carbon nanotubes (CNTs) -tubes made of carbon with nanosized diameters -have attracted increasing attention in biomedicine because of their unique structures and properties, being the strongest and stiffest materials yet found in terms of tensile strength and elastic modulus. With functionalization, CNTs have been used as nanocarriers for nucleic acids including siRNA, oligonucleotides, and RNA/DNA aptamers. 380 Amino-functionalized multiwalled CNTs deliver proprietary toxic siRNA to human lung carcinoma cells. Appropriately designed amino-functional segments on the CNTs promote internalization in the cell and gene silencing. 382 Cationic single-walled CNTs deliver siRNA to Lewis lung carcinoma cells. Despite the widespread use of carriers for RNA delivery, naked RNA has also been delivered in vivo , including delivery of mRNA by intramuscular, subcutaneous, or intradermal injections; the latter can promote wound healing by in situ expression of specific proteins in the skin. Local injections circumvent complications associated with systemic administration such as clearance from the bloodstream. Naked mRNA administered subcutaneously produces a more efficient translation of the protein than mRNA-loaded nanoparticles. PEGylation allows protein drugs to avoid the immune response 392 , but it also improves the surface properties of biomolecules and drug delivery systems. It blocks surface access by steric hindrance increasing the circulation time in blood. Thus, it may improve pharmacokinetic properties and enhance the efficacy of drugs, including RNA therapeutics. PEGylation of the RNA nanocarriers reduces nonspecific interactions with serum proteins and prevents recognition by the immune system, increasing the blood circulation time. PEGylation stabilizes RNAs with longer PEGs stabilizing oligonucleotide better than shorter ones. The aptamer drug Macugen comprises an oligonucleotide modified with branched 40 kDa PEG at the 5' terminus, thus enhancing the nuclease resistance of the PEG-aptamer conjugate. PEGylation markedly improves the pharmacokinetics and boosts the neutralizing activity anti-IL-17A aptamers, an important advance in the development of therapeutic aptamers.