title: Choline alkylsulfates--new promising green surfactants.
abstract: In this work we show how a new promising green and highly water-soluble surfactant can be designed based on recent progress in the knowledge of counterion-headgroup binding and crystallization behavior. The result is the combination of a most classical surfactant anion, dodecylsulfate (DS), with choline (Ch), a natural green cation. The advantage of the physiological metabolite choline is its bulky structure that prevents ChDS from easy crystallization and thus leads to a considerable lowering of the Krafft point down to 0°C. The counterion-headgroup binding is reflected by the aqueous phase behavior of ChDS. Conductivity, surface tension, and cryo-TEM measurements allow the characterization of the dilute micellar region, while the penetration scan technique enables the establishment of a preliminary aqueous phase diagram. In addition, the influence of different mono- and divalent salts on the solubility of ChDS is investigated. The results are compared to the alkali sulfate and alkylcarboxylate homologs, and reveal that ChDS is less sensitive towards addition of salts than, for instance, choline carboxylates due to an increased counterion-headgroup association. Further, cytotoxicity tests on HeLa and SK-Mel 28 cells are presented and compared to other surfactants, showing that ChDS is no more harmful than its sodium counterpart SDS. Taken together, our findings highlight that the harmless green cation choline is of great potential for the design of new surfactants.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Klein
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kellermeier
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Didier
authors.initials: D
authors.lastname: Touraud
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Müller
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany. Electronic address: werner.kunz@chemie.uni-regensburg.de.
authors.forename: Werner
authors.initials: W
authors.lastname: Kunz
mesh_terms: D017738:Alkanesulfonic Acids / Q000737:chemistry / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002794:Choline / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006367:HeLa Cells; D006801:Humans; D013329:Structure-Activity Relationship; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D017738:Alkanesulfonic Acids; D000970:Antineoplastic Agents; D013501:Surface-Active Agents; C017273:dodecylsulfonic acid; D002794:Choline