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  • Physicochemical and antibacterial properties of surfactant mixtures with quaternized chitosan microgels.

Physicochemical and antibacterial properties of surfactant mixtures with quaternized chitosan microgels.

Carbohydrate polymers (2013-03-19)
Kristopher E Richardson, Zheng Xue, Yan Huang, Youngwoo Seo, Yakov Lapitsky
ABSTRACT

Antibacterial surfactant mixtures attract widespread interest in the design of consumer product formulations, but often use toxic biocidal agents such as cationic surfactants, triclosan or bleach. To address this, we explored replacing these toxic ingredients with quaternized chitosan microgels, which combine high antibacterial activity with cytocompatibility with mammalian cells. Specifically, three essential properties of microgel mixtures with model anionic (sodium dodecyl sulfate, SDS) and nonionic (Triton X-100, TX-100) surfactants (and with SDS/TX-100 mixtures) were investigated: (1) colloidal stability, (2) antibacterial activity, and (3) hydrophobe solubilization. Additionally, the effect of surfactant on dispersion turbidity, which can be important in the formulation of aesthetically-appealing products, was explored. The microgels formed more-stable dispersions when mixed with nonionic TX-100, but quickly precipitated when mixed with the electrostatically-binding SDS and SDS/TX-100 surfactant systems at fairly-low (millimolar) surfactant concentrations. At higher SDS concentrations the microgels were redispersed and ultimately dissolved when mixed with only SDS, but remained precipitated in SDS/TX-100 mixtures. Furthermore, the electrostatic binding of SDS to quaternized chitosan diminished its antibacterial activity and (because the SDS-bearing mixtures with strong biocidal activity were limited to low surfactant concentrations) also resulted in limited hydrophobe solubilization. Conversely, microgels mixed with TX-100 maintained their biocidal activity even when the surfactant was in excess, and exhibited good solubilization properties. This suggests that surfactant-based products that use quaternized chitosan microgels as antibacterial agents should optimally be formulated using nonionic surfactants.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Triton X-100 solution, BioUltra, for molecular biology, ~10% in H2O
Sigma-Aldrich
Triton X-305 solution, 70% in H2O
Sigma-Aldrich
Triton X-102
Octoxinol 10, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, for molecular biology, ≥98.5% (GC), free-flowing, Redi-Dri
Sigma-Aldrich
Triton X-100, laboratory grade
Sigma-Aldrich
Triton X-100, BioXtra
Sigma-Aldrich
Triton X-100, for molecular biology
Sigma-Aldrich
Sodium dodecyl sulfate, BioXtra, ≥99.0% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, ReagentPlus®, ≥98.5% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, 92.5-100.5% based on total alkyl sulfate content basis
Sigma-Aldrich
Triton X-100, peroxide- and carbonyl-free
Sigma-Aldrich
Sodium dodecyl sulfate, ≥90% ((Assay))
Sigma-Aldrich
Triton X-45
Sigma-Aldrich
Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, for molecular biology, ≥98.5% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate solution, BioUltra, for molecular biology, 20% in H2O
Sigma-Aldrich
Sodium dodecyl sulfate, ≥98.0% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate solution, BioUltra, for molecular biology, 10% in H2O
Supelco
Sodium dodecyl sulfate, suitable for ion pair chromatography, LiChropur, ≥99.0%
Sigma-Aldrich
Sodium dodecyl sulfate, ACS reagent, ≥99.0%
Sigma-Aldrich
Sodium dodecyl sulfate, BioUltra, for molecular biology, ≥99.0% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, tested according to NF, mixture of sodium alkyl sulfates consisting mainly of sodium dodecyl sulfate
Sigma-Aldrich
Sodium dodecyl sulfate, ≥99.0% (GC), dust-free pellets