A novel method for DNA delivery into bacteria using cationic copolymers

Amphiphilic copolymers have a wide variety of medical and biotechnological applications, including DNA transfection in eukaryotic cells. Still, no polymer-primed transfection of prokaryotic cells has been described. The reversible addition-fragmentation chain transfer (RAFT) polymer synthesis technique and the reversible deactivation radical polymerization variants allow the design of polymers with well-controlled molar mass, morphology, and hydrophilicity/hydrophobicity ratios. RAFT was used to synthesize two amphiphilic copolymers containing different ratios of the amphiphilic poly[2-(dimethyl-amino) ethyl methacrylate] and the hydrophobic poly [methyl methacrylate]. These copolymers bound to pUC-19 DNA and successfully transfected non-competent Escherichia coli DH5α, with transformation efficiency in the range of 103 colony-forming units per µg of plasmid DNA. These results demonstrate prokaryote transformation using polymers with controlled amphiphilic/hydrophobic ratios.

Effect of urea on biomimetic aggregates

The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities.