Controlled compaction and decompaction of DNA by zwitterionic surfactants

July 28, 2017


Controlled compaction and decompaction of DNA by zwitterionic surfactants


Lei Feng, Lu Xu, Jingcheng Hao, Shuli Dong




Colloids and Surfaces A: Physicochemical and Engineer Aspects


Controlled compaction and decompaction of DNA by zwitterionic surfactants, alkyldimethylamine oxides (CnDMAO, n = 10, 12, and 14), were investigated by various analytical tools. It was found that DNA could effectively be compacted by cationic micelles of CnDMAOH+ which were produced by the protonation of CnDMAO in acidic media leading to the formation of water-insoluble CnDMAOH+/DNA complexes. The DNA molecules were compacted at pH 4–5 when the concentration of C10DMAOH+, C12DMAOH+, and C14DMAOH+ reached 8.0, 1.6, and 0.9 mmol L−1, respectively. Interestingly, the precipitates of CnDMAOH+/DNA complexes can re-dissolve which indicated that the DNA molecules were released from the complexes by regulating the pH of the solution to ∼4 and increasing the surfactant concentration to 40, 9.0, and 1.8 mmol L−1 for C10DMAOH+, C12DMAOH+, and C14DMAOH+, respectively. This phenomenon was attributed to the hydrogen bonding formed between cationic CnDMAOH+ and zwitterionic CnDMAO species. These hydrogen-bonded species screen the electrostatic forces between the positively charged CnDMAOH+ micelles and the negatively charged backbones of DNA. Our results demonstrated that the release of DNA from the CnDMAOH+/DNA precipitates depended on the concentration of cationic CnDMAOH+ and the pH of the solution. Compared with the conventional release of DNA by the addition of β-cyclodextrin, the present strategy allowed for a specific controlled release, which favored the penetration of DNA into cells and could protect the DNA molecules from nucleases degradation.




Circular dichroism, DNA structure, Vesicle interactions, Biochemistry