title: Investigation of the reversibility of the unimer-to-aggregate transition in block copolymers by surface tension-measurements.
abstract: Two DNA-block copolymers, poly(caprolactone)-DNA and poly(methyl metacrylate)-DNA, were synthesized by conjugation of a short single strand of DNA (12 or 22mer) to a single reactive group at one end of the synthetic polymer. These polymers self-assemble in water, without the need of any cosolvent, forming micelle-like aggregates that were imaged by TEM. The solution behavior of the bioconjugated polymers was investigated by surface tension measurements. In the direction of dilution, the surface tension was measured using a down-scaled Wilhelmy plate method. To proceed in the reverse direction (concentration), we measured the surface tension of a sessile drop during its evaporation. This latter method was firstly validated using ionic and non-ionic surfactants, including polymeric surfactants. It was then applied to investigate the unimer to micelles transition of the DNA-block copolymers. In all cases, a reversible transition was observed demonstrating the existence of a critical micellar concentration, close to 0.01 mmol L(-1) for all the conjugates. The CMC was only slightly influenced by the length of the hydrophilic DNA block.
authors.affiliation: Université de Toulouse, Laboratoire des IMRCP, UMR5623 CNRS, 118 Route de Narbonne, F-31062 Toulouse Cedex 9, France.
authors.forename: Renée
authors.initials: R
authors.lastname: Mayap Talom
authors.forename: Gad
authors.initials: G
authors.lastname: Fuks
authors.forename: Christophe
authors.initials: C
authors.lastname: Mingotaud
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gineste
authors.forename: Fabienne
authors.initials: F
authors.lastname: Gauffre
mesh_terms: D001483:Base Sequence; D004277:DNA, Single-Stranded / Q000138:chemical synthesis / Q000737:chemistry*; D008823:Micelles; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000138:chemical synthesis / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D004277:DNA, Single-Stranded; D008823:Micelles; D011091:Polyesters; D013501:Surface-Active Agents; C016240:polycaprolactone; D019904:Polymethyl Methacrylate