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The physical chemistry of DNA: implications of DNA-cationic cosolute interactions
Speaker(s): Prof. Björn Lindman, Sch. of Materials Science & Engineering, NTU, Singapore. Dept. of Chemistry, Coimbra University, Portugal. Physical Chemistry, University of Lund, Sweden.
When: 30 November 2016 (11:30am - 12:30pm)
Where: SBS CR2 (Level 1)
Type: Seminars

Understanding the physical chemistry of DNA is an integral part of much of SCELSE’s research, from genomic sequencing to biofilm matrix. DNA is a strongly negatively charged polyelectrolyte that associates strongly with cationic co-solutes. This in turn leads to strong associative phase separation. Cationic lipids and surfactants are efficient in compacting DNA and can also be efficient transfection agents. Professor Lindman will present an overview of DNA-surfactant interactions, illustrating the binding of surfactants and other cations to DNA in bulk and their consequences in terms of phase behaviour and compaction. A general understanding of the interactions between DNA and oppositely charged agents, particularly their phase behaviour, informed the development of novel DNA-based materials, including gels and gel particles. Gels prepared by covalent cross-linking of DNA allowed DNA-cosolute interactions to be monitored. Furthermore, the associative phase separation and interfacial diffusion behaviour of DNA complexes led to novel DNA gel particles produced using not covalent cross-linkers or organic solvents, but instead only surfactants, polycations and proteins. Interestingly, stronger interactions of ssDNA compared with dsDNA, suggests that DNA amphiphilicity plays a dominant role in defining its interactions with cationic cosolutes. Such knowledge could lead to optimised methods for extracting and processing DNA for genomic sequencing, but also help us describe the role DNA plays in establishing the emergent properties of biofilm as eDNA.