Hannah Boyd1, Juan F Gonzalez-Martinez2, Rebecca J L Welbourn3, Philipp Gutfreund4, Alexey Klechikov5, Carolina Robertsson6, Claes Wickström6, Thomas Arnebrant2, Robert Barker7, Javier Sotres8. 1. Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden. Electronic address: hannah.boyd@mau.se. 2. Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden. 3. ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK. 4. Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France. 5. Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. 6. Department of Oral Biology and Pathology & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden. 7. School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, UK. 8. Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden. Electronic address: javier.sotres@mau.se.
Abstract
HYPOTHESIS: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure. EXPERIMENTS: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry. FINDINGS: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.
HYPOTHESIS: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure. EXPERIMENTS: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry. FINDINGS: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.
Authors: Gurdeep Chahal; Macarena P Quintana-Hayashi; Meztlli O Gaytán; John Benktander; Medea Padra; Samantha J King; Sara K Linden Journal: Front Cell Infect Microbiol Date: 2022-06-17 Impact factor: 6.073
Authors: Hannah Boyd; Juan F Gonzalez-Martinez; Rebecca J L Welbourn; Kun Ma; Peixun Li; Philipp Gutfreund; Alexey Klechikov; Thomas Arnebrant; Robert Barker; Javier Sotres Journal: Sci Rep Date: 2021-06-21 Impact factor: 4.379