Physicochemical Properties of Lipids and Macromolecules in Higher Level Organization

Hernández-Borrell, Jordi; Doménech, Òscar; Keough, K. M. W.

doi:10.1007/978-3-319-30277-5_2

Cited by 1 publication

(1 citation statement)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, suitable methods are required not only to mimic the bacterial lipid membrane but also to provide information at the molecular level. In this context, Langmuir monolayers have been proven efficient models of both Gram-positive and Gram-negative bacteria membranes owing to the control of lateral packing and membrane composition. − For instance, the mechanisms of action of antimicrobial peptides have been successfully accessed on Langmuir models of S. aureus, Streptococcus mutan, , Salmonella enterica serovar Typhimurium, and E.…”

Section: Introductionmentioning

confidence: 99%

Role of Toluidine Blue-O Binding Mechanism for Photooxidation in Bioinspired Bacterial Membranes

2019

View full text Add to dashboard Cite

The alarming increase in bacterial resistance to antibiotics has demanded new strategies for microbial inactivation, which include photodynamic therapy whose activity relies on the photoreaction damage to the microorganism membrane. Herein, the binding mechanisms of the photosensitizer toluidine blue-O (TBO) on simplified models of bacterial membrane with Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG) were correlated to the effects of the photoinduced lipid oxidation. Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were also used as a reference of mammalian membranes. The surface pressure isotherms combined with polarization-modulated infrared reflection absorption spectroscopy revealed that TBO expands DOPC, DOPE, and DOPG monolayers owing to electrostatic interactions with the negatively charged groups in the phospholipids, with a stronger adsorption on DOPG, which has a net surface charge. Light irradiation made the TBO-containing DOPC and DOPE monolayers less unstable as a result of the singlet oxygen ( 1 O 2 ) reaction with the chain unsaturation and hydroperoxide formation. In contrast, the decreased stability of the irradiated TBO-containing DOPG monolayer suggests the cleavage of carbon chains. The anionic nature of DOPG allowed a deeper penetration of TBO into the chain region, favoring contact-dependent reactions between the excited triplet state of TBO and lipid unsaturations or/and hydroperoxide groups, which is the key for the cleavage reactions and further membrane permeabilization.

show abstract