Antibacterial Pickering emulsions stabilized by bifunctional hairy nanocellulose

Mandana Tavakolian; Roya Koshani; Nathalie Tufenkji; Theo G M van de Ven

doi:10.1016/j.jcis.2023.04.033

Antibacterial Pickering emulsions stabilized by bifunctional hairy nanocellulose

J Colloid Interface Sci. 2023 Aug:643:328-339. doi: 10.1016/j.jcis.2023.04.033. Epub 2023 Apr 13.

Authors

Mandana Tavakolian¹, Roya Koshani², Nathalie Tufenkji³, Theo G M van de Ven⁴

Affiliations

¹ Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada; Pulp and Paper Research Centre, McGill University, 3420 University Street, Montreal, QC H3A 2A7, Canada; Quebec Centre for Advanced Materials (QCAM), 3420 University Street, Montreal, QC H3A 2A7, Canada. Electronic address: mandana.tavakolian@mail.mcgill.ca.
² Pulp and Paper Research Centre, McGill University, 3420 University Street, Montreal, QC H3A 2A7, Canada; Quebec Centre for Advanced Materials (QCAM), 3420 University Street, Montreal, QC H3A 2A7, Canada; Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada. Electronic address: roya.koshani@mcgill.ca.
³ Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada; Quebec Centre for Advanced Materials (QCAM), 3420 University Street, Montreal, QC H3A 2A7, Canada. Electronic address: nathalie.tufenkji@mcgill.ca.
⁴ Pulp and Paper Research Centre, McGill University, 3420 University Street, Montreal, QC H3A 2A7, Canada; Quebec Centre for Advanced Materials (QCAM), 3420 University Street, Montreal, QC H3A 2A7, Canada; Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada. Electronic address: theo.vandeven@mcgill.ca.

PMID: 37080040
DOI: 10.1016/j.jcis.2023.04.033

Abstract

Hypothesis: Pickering emulsions, defined as emulsions that are stabilized by colloidal particles, provide dispersion stability by preventing coalescence of the dispersed phase. In this study, we used a bifunctional hairy nanocellulose (BHNC) bearing both aldehyde and carboxylic acid groups as an stabilizer. We hypothesize that these particles as Pickering stabilizers can effectively reside at the oil-water interface, better than hairy nanocelluloses containing only carboxyl groups or aldehyde groups, and provide long-term stability without the need of any surfactants.

Experiments: Varying concentrations of BHNC were tested to explore the optimal concentration that provides emulsion stability. The effects of various preparation conditions such as salt and pH were also studied. Finally, carvacrol, an antibacterial essential oil, was loaded in the oil phase to develop antibacterial emulsions.

Findings: It was shown that a 1% BHNC suspension provides 90% and 80% stability for a duration of 30 and 60 days, respectively. A theoretical model using nuclear magnetic resonance relaxometry data is developed to prove that only a monolayer of BHNC covers oil droplets. Increasing the concentration of BHNC decreased the size of oil droplets, which as a result increases the surface area available for monolayer coverage. It was also shown that the antibacterial emulsions are highly effective against Gram-negative (i.e. E. coli) and Gram-positive (i.e. S. aureus) bacteria. Accordingly, BHNC as a highly functionalized bio-derived colloidal particle opens new opportunities for engineering highly stable Pickering emulsions.

Keywords: Antibacterial emulsions; Bifunctional cellulose nanocrystal; Hairy nanocellulose; Pickering emulsions.

MeSH terms

Emulsions
Escherichia coli*
Particle Size
Staphylococcus aureus*
Surface-Active Agents

Substances

Emulsions
Surface-Active Agents