Abstract
The aim of the study was to determine the bactericidal properties of popular medical, pharmaceutical, and cosmetic ingredients, namely chitosan (Ch), hyaluronic acid (HA), and titanium dioxide (TiO2). The characteristics presented in this paper are based on the Langmuir monolayer studies of the model biological membranes formed on subphases with these compounds or their mixtures. To prepare the Langmuir film, 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) phospholipid, which is the component of most bacterial membranes, as well as biological material-lipids isolated from bacteria Escherichia coli and Staphylococcus aureus were used. The analysis of the surface pressure-mean molecular area (π-A) isotherms, compression modulus as a function of surface pressure, CS−1 = f(π), relative surface pressure as a function of time, π/π0 = f(t), hysteresis loops, as well as structure visualized using a Brewster angle microscope (BAM) shows clearly that Ch, HA, and TiO2 have antibacterial properties. Ch and TiO2 mostly affect S. aureus monolayer structure during compression. They can enhance the permeability of biological membranes leading to the bacteria cell death. In turn, HA has a greater impact on the thickness of E. coli film.
Highlights
The cell envelope of Gram-negative bacteria consists of two distinct layers, the outer (OM) and the inner (IM) membranes, separated by the periplasm with a thin layer of peptidoglycan
We made an effort to determine whether chitosan, TiO2, and hyaluronic acid and/or their mixtures cause disturbances in the structure of model biological membranes, formed of the synthetic material 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG) phospholipid, which is the component of most bacterial membranes, as well as biological material
The greatest changes of compression modulus and average surface area per molecule occurred in the presence of Ch and/or TiO2 at pressures values close to those corresponding to the biological membranes
Summary
The cell envelope of Gram-negative bacteria consists of two distinct layers, the outer (OM) and the inner (IM) membranes, separated by the periplasm with a thin layer of peptidoglycan. Both membrane leaflets of the IM are mostly composed of phospholipids. The OM is an asymmetric lipid bilayer containing mainly phospholipids in the inner leaflet, whereas the outer leaflet is mainly composed of lipopolysaccharide (LPS) This strict OM asymmetry is important for the proper functioning of the bacterial cell, as it constitutes a permeability barrier, preventing the penetration of toxic compounds inside of the cell [1]. It has been proven that their application allows the assessment of changes in the physicochemical properties of lipid layers caused by foreign substances [3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
