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Lauryl gallate (LG) is an antioxidant agent. However, it exhibits poor solubility in water. Its interactions with the membrane result in structure evolution thus affecting the membrane functionality. In this paper the Brewster angle microscope coupled with the Langmuir trough was applied to determine the morphology, phase behaviour, thickness and miscibility of ternary Langmuir monolayers with equal mole fractions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC); 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and an increasing mole fraction of LG. The results were discussed as regards analogous systems where cholesterol (Chol) was the third component. Moreover, the phosphatidylcholine–lauryl gallate (PC–LG) interactions were monitored by the attenuated total reflectance Fourier transform infrared spectroscopy and time-of-flight secondary ion mass spectrometry. Besides lipid composition, the addition of LG was found to be a significant factor to modulate the model membrane properties. The LG molecules adjust themselves to the PC monolayer structure. The hydrophobic fragment is dipped into the membrane interior while the hydroxyl groups of phenolic gallate moiety associate with the polar groups of PC mainly through hydrogen bonding inducing the compacting effect. LG is found to be deeply submerged within DOPC, closer to the double bonds, and its insertion practically does not affect the DPPC/DOPC membrane fluidity. This is crucial for getting more profound insight into the role of LG in stabilizing the non-raft domains, mostly exposed to oxidation in which LG can co-localize and serve its antioxidant function.

Interactions of functional additives SPS (bis-(sodium-sulfopropyl)-disulfide), MPS (3‑Mercapto-1-Propanesulfonate), and Cl accumulated and incorporated on/into a copper electrodeposited layer were studied using time-of-flight secondary-ion mass spectrometry (TOF-SIMS) in combination with cyclic voltammetry measurements (CV). It was shown that the Cl and MPS surface coverage is dependent on the applied overpotential and concentration of Cl, SPS, or MPS in the solution. Detailed discussion on the mechanism of yielding CH2SO3−, C3H5SO3−, CuSC3H6SO3−, and CuS− fragments and their assignment to the gauche or trans conformation was proposed. The mechanism of the process of incorporation and re-adsorption of MPS on/into a copper surface under electrochemical conditions without and with chloride ions and its impact on electrochemical properties was proposed. Moreover, it was shown that the presence of chloride ions, the ratio gauche/trans of MPS molecules, as well as the ratio chloride/thiols demonstrate a high impact on the accelerating abilities. Comparative studies conducted under open circuit potential conditions on the nitinol and copper substrate allowed for the identification of specific reactions/interactions of MPS, or SPS and Cl ions on the nitinol and copper surface.

The paper deals with the cholesterol-cyclosporine A (Chol-CsA) monolayers at the air/water interface investigated using the Langmuir trough coupled with the Brewster's angle microscopy. The compressed films were transferred onto the PEEK polymer support by means of the Langmuir-Blodgett technique. To improve molecules adhesion and organization the PEEK surface was treated with air plasma before thin films deposition. The obtained surfaces were characterized by means of atomic force microscope (AFM). Then, the wettability of the supported monolayers was determined by the contact angle measurements. Finally, the surface free energy and its components were evaluated from the theoretical approach proposed by van Oss et al. The obtained results reveal correlation between properties of the Langmuir monolayers at the air/water interface and those of the Langmuir-Blodgett films on PEEK. This was found to be helpful for understanding the wettability of organized molecular films on the polymer support as far as biocompatibility improve is concerned. The preparation of films with defined polarity and various compositions is an important step in the development of polymer surfaces with increased biofunctionality. It is believed that the results presented in this paper can be exploited in the in vivo studies.