Protein expression requires the availability of the promoter sequence for RNA polymerase binding and the open reading frame (ORF) sequence for RNA transcript synthesis and termination signal sequence followed by translation and polypeptide formation. Thus, considering the limited size of the uncondensed parts of partially condensed DNA and the irreversible binding of DNA to PEI-SWCNTs (see above), we hypothesized that a gene with a short sequence would be more likely to be fully accessible in the uncondensed parts of the DNA and thus more likely to be available to the cellular transcription machinery. By contrast, a gene with a long sequence is more likely to be present in both the condensed and uncondensed conformations and hence would not be fully available to the transcription machinery. These differences in the condensed conformations of the plasmid and thus the probability of accessibility of the genes could lead to facilitated transcription of small genes and hindered transcription of long genes (ORFs).