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.

Polyetheretherketone (PEEK) biomaterial is a polymer which has been widely used since the early 90s as a material for human bone implant preparations. Nowadays it is increasingly used due to its high biocompatibility and easily modeling, as well as better mechanical properties and price compared to counterparts made of titanium or platinum alloys. In this paper, air low-temperature and pressure plasma was used to enhance PEEK adhesive properties as well as surface sterilization. On the activated polymeric carrier, biologically-active substances have been deposited with the Langmuir-Blodgett technique. Thereafter, the surface was characterized using optical profilometry, and wettability was examined by contact angle measuring. Next, the contact angle hysteresis (CAH) model was used to calculate the surface free energy of the modified surface of PEEK. The variations of wettability and surface free energy were observed depending on the deposited monolayer type and its components.

Polyetheretherketone (PEEK) is a highly biocompatible polymer widely used in medicine as an implant production material. In this article, the PEEK surface was characterized in terms of its wettabillity properties after the physicochemical modifications by treatment with the low‐temperature air plasma and covering with the Langmuir–Blodgett (LB) monolayers of polypeptide (cyclosporine A, CsA) and/or phospholipid (1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine, DPPC). The LB deposition was preceded by the analysis of miscibility and morphology of monolayers at the air/water interface by means of the Langmuir technique and Brewster angle microscopy (BAM). Then, wettability of the polymer‐supported films was evaluated by the contact angle measurements of three probe liquids of different characters (two polar—water and formamide, one apolar—diiodomethane). The measured contact angles allowed for determination of the surface free energy and its components based on the Lifshitz‐van der Waals/acid–base (LWAB) approach. Some relations between the kind and magnitude of interactions within the model membranes on the water subphase and those of the PEEK‐supported membranes with the liquids were found out. The results allowed obtaining the interesting models of biological coatings with potential applications.

Chitosan (Ch) is a polysaccharide mainly used in cosmetics, biotechnology and medicine owing to its biocompatibility, biodegradability and low cytotoxicity. One of the challenges is the development of mechanisms responsible for its action in biomedical applications. In this aspect, it is important to get more profound insight into the chitosan interactions with peptide drugs at the molecular level. The drug of interests was a cyclosporine A (CsA) known for its effective immunosuppressive action against transplant rejection. In this study, the Langmuir technique was used to determine the interactions between Ch (dissolved in the subphase) and the monomolecular films of CsA spread at the air-chitosan solution interface. The surface pressure versus the area per molecule (p-A) measurements of the CsA monolayers on the subphase with or without Ch was conducted at 20°C and 37°C. The Ch insertion into the CsA monolayers was monitored by relative changes in the DA A area and the compression modulus. The findings demonstrate that the presence of Ch in the subphase provides the CsA monolayer expansion and affects the molecular packing and ordering in the temperaturedependent way. The temperature increase induces conformational changes in the peptide monolayers being a decisive factor which influences the kind and strength of interactions between Ch and CsA.

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