Langmuir Monolayer Techniques for the Investigation of Model Bacterial Membranes and Antibiotic Biodegradation Mechanisms

Abstract

The amounts of antibiotics of anthropogenic origin released and accumulated in the environment are known to have a negative impact on local communities of microorganisms, which leads to disturbances in the course of the biodegradation process and to growing antimicrobial resistance. This mini-review covers up-to-date information regarding problems related to the omnipresence of antibiotics and their consequences for the world of bacteria. In order to understand the interaction of antibiotics with bacterial membranes, it is necessary to explain their interaction mechanism at the molecular level. Such molecular-level interactions can be probed with Langmuir monolayers representing the cell membrane. This mini-review describes monolayer experiments undertaken to investigate the impact of selected antibiotics on components of biomembranes, with particular emphasis on the role and content of individual phospholipids and lipopolysaccharides (LPS). It is shown that the Langmuir technique may provide information about the interactions between antibiotics and lipids at the mixed film surface (π–A isotherm) and about the penetration of the active substances into the phospholipid monolayer model membranes (relaxation of the monolayer). Effects induced by antibiotics on the bacterial membrane may be correlated with their bactericidal activity, which may be vital for the selection of appropriate bacterial consortia that would ensure a high degradation efficiency of pharmaceuticals in the environment.

Factors Influencing the Bioavailability of Organic Molecules to Bacterial Cells—A Mini-Review

“…In numerous cases, these characteristics do not allow compounds to penetrate cells, because the permeability of the cell membrane is too low for them [ 36 , 37 ]. Consequently, the access of these compounds to microorganisms is limited and inefficient, which slows down the biodegradation process, even when biodegradation is not restricted by the metabolic capacity of the cells [ 38 , 39 ].…”

Interaction of Lipophilic Cytarabine Derivatives with Biomembrane Model at the Air/Water Interface

“…The interaction of drugs or prodrugs with the cell membrane is a crucial aspect of explaining and understanding their mechanism of action [ 12 , 13 , 14 , 15 ]. However, the study of this interaction is problematic due to the complexity of the eukaryotic membrane structure.…”

“…Moreover, the lipid fraction is subjected to continuous morphological and behavioral changes since it is composed of phospholipids, organized into a bilayer structure, that deeply modify their disposition and thus their permeability depending on environmental pH, temperature and cholesterol content. Interactions between drug and real biomembranes, firstly due to the protein nature of the latter, are then difficult to study and understand from both biological and physicochemical perspectives [ 12 , 13 , 14 , 15 ]. For this reason, it is necessary to employ simplified models of biomembranes made of one or more phospholipids that resemble the main cell membrane’s components; multilayer vesicles (particularly liposomes) and monolayers (e.g., Langmuir monolayers) are widely studied and commonly used as biomembrane models.…”

“…For this reason, it is necessary to employ simplified models of biomembranes made of one or more phospholipids that resemble the main cell membrane’s components; multilayer vesicles (particularly liposomes) and monolayers (e.g., Langmuir monolayers) are widely studied and commonly used as biomembrane models. These simplified models permit easily predicting possible interplays between phospholipids and exogenous molecules with potential biological activity, such as variations induced by these compounds on the diffusion process, their miscibility in bilayers or monolayers, and the overall system stability [ 12 , 13 , 14 , 15 ].…”

Special Issue “Biomembranes and Biomimetic Membranes—From Model Analysis to ‘In Vivo’ Study”

“…The Special Issue closes with a review paper by Rojewska et al [3] on the use of monolayer experiments undertaken to investigate the impact of selected antibiotics on components of biomembranes, with particular emphasis on the role and content of individual phospholipids and lipopolysaccharides (LPS). The authors noticed that, in combination with spectroscopic techniques, the Langmuir method may help to establish preferred antibiotic orientations and the depths of its insertion into the cell membrane.…”