Insights on the DNA Stability in Aqueous Solutions of Ionic Liquids

Abstract

Deoxyribonucleic acid (DNA) carries the genetic information essential for the growth and functioning of living organisms, playing a significant role in life sciences research. However, the long-term storage and preservation of DNA, while ensuring its bioactivity, are still current challenges to overcome. In this work, aqueous solutions of ionic liquids (ILs) were investigated as potential preservation media for double stranded (dsDNA). A screening of several ILs, by combining the cholinium, tetrabutylammonium, tetrabutylphosphonium, and 1-ethyl-3-methylimidazolium, cations with the anions bromide, chloride, dihydrogen phosphate, acetate, and glycolate, was carried out in order to gather fundamental knowledge on the molecular features of ILs that improve the dsDNA stability. Different IL concentrations and the pH effect were also addressed. Circular dichroism (CD) spectroscopy was used to evaluate the conformational structure and stability of dsDNA. IL-DNA interactions were appraised by UV-Vis absorption spectrophotometry and 31 P nuclear magnetic resonance (NMR) spectroscopy. The results obtained demonstrate that pH has a significant effect towards the dsDNA stability. Amongst the ILs investigated, cholinium-based ILs are the most promising class of ILs to preserve the dsDNA structure, in which electrostatic interactions between the cholinium cation and the DNA phosphate groups play a significant role as demonstrated by the 31 P NMR data, being more relevant at higher IL concentrations. On the other hand, the denaturation of dsDNA mainly occurs with ILs composed of more hydrophobic cations and able to establish dispersive interactions with the nucleobases environment. Furthermore, the IL anion has a weaker impact when compared to the IL cation effect to interact with DNA molecules. The experimental data of this work provide relevant fundamental knowledge for the application of ILs in the preservation of nucleic acids, being of high relevance in the biotechnology field.

Nucleic Acids Based Polyelectrolyte Complexes: Their Complexation Mechanism, Morphology, and Stability

“…In addition to the choline-based ILs, other cation–anion combinations were also explored as potential stabilizing media for DNA. ,,− In a recent publication, Dinis et al examined DNA stability in a series of hydrated IL solutions . Different ILs were prepared by combination of cholinium, tetrabutyl­ammonium, tetrabutyl­phosphonium, and 1-ethyl-3-methyl­imidazolium cations with bromide, chloride, dihydrogen phosphate, acetate, and glycolate anions.…”

“…While DNA or RNA in an aqueous buffer solution can be handled with reasonable stability at room temperature, its storage requires refrigeration at −20 °C (short-term storage) or −80 °C (long-term storage). , The low temperature is necessary to prevent nucleic acids from chemical and enzymatic degradation, but at the same time it also limits the application range of nucleic acids as polymeric materials. It has been shown that ionic liquids (ILs) interact with DNA to form complexed structures, leading to the stabilization of DNA for extended periods of time at room temperature. − The stabilization mechanism is mainly attributed to electrostatic and hydrophobic interactions, and studies exploring the stability of DNA in various ILs have been reported. ,,− Moreover, the utilization of DNA–IL complex has also led to new material development including ion conductive films and templates for nanoparticle synthesis. − …”

Harnessing DNA for Immunotherapy: Cancer, Infectious Diseases, and Beyond

“…First, despite the generally stable nature of DNA, it may also lose bioactivity in the presence of DNase and some chemicals. [ 107 ] Second, the difficulty in the delivery of DNA into nuclear also dampens the effectiveness of vaccination. Moreover, the proteins produced under the guidance of the DNA in the body may be taken for endogenous substances, which have the possibility to induce immune tolerance rather than immune activation.…”

“…DNA is reported to be stable in most cases, but it can also interact with other chemicals as well as be degraded by DNases. [ 107 ] DNA vaccines may be exposed to a complex environment in vivo for a certain period of time before transfection taking place. [ 106b ] Besides, as DNA naturally exists in the human body, pharmacokinetics study of exogenous DNA is important that may affect both the effectiveness and the systemic toxicity.…”

Nanotechnology-Based Strategies to Overcome Current Barriers in Gene Delivery

“…Gene therapeutics are internalized to intracellular vesicles called endosomes, which contain many digestive enzymes that can degrade nucleic acids. Moreover, endosomal pH acidifies progressively as they transition from early to late endosomes and finally to lysosomes, nucleic acids, especially DNA, are not stable at such a low pH [28]. Therefore, gene therapeutics must escape the endosomal pathway in its early stage to avoid being exposed to low pH and catalytic enzymes.…”