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