The wetting properties of Langmuir-Blodgett and Langmuir-Schaefer films formed by DPPC and POSS compounds.

The possibility of modification of surface wettability is especially desirable in implantology. This effect is achieved by coating a given material with thin films containing nanoparticles of different chemical properties. In recent years, much interest has been paid to supported phospholipid bilayers (SPBs), because they can be exploited in novel biotechnological devices such as biosensors and mimetic membrane-coated implants. In view of the above, we decided to study the modification of wetting properties of phospholipid layer by two types of polyhedral oligomeric silsesquioxanes (POSS) with different functional groups attached to the silica open-cage. The POSS and phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC) were vertically (Langmuir-Blodgett; LB) and horizontally (Langmuir-Schaefer; LS) deposited on quartz substrates to form a thin layer structure. The advancing contact angles on the modified surface coated with thin films were measured. The surface free energy (SFE) of DPPC, POSS and their mixed DPPC/POSS films was estimated by using Owens-Wendt-Rabel-Käelbe (OWRK) method. It was shown that the chemical structure of POSS used as a modifier influence the wetting properties of modified quartz surface. Incorporation fluoroalkyl-POSS into DPPC monolayer leads to obtaining a more hydrophobic film, while the addition of polyethylene glycol-POSS creates a more hydrophilic film. The transfer of the film with a more condensed structure led to a more hydrophobic material. The deposition technique (horizontal or vertical) had a particular impact on the modification of wettability of quartz surface coated with monocomponent fluoroalkyl-POSS film, whereas for the modification with mixed DPPC/POSS systems the choice of transfer method was not so significant.

Balance between epithelial and stromal marker expression and distribution in primary culture model of porcine endometrium during real-time cell proliferation..

The similarity between humans and pigs, when it comes to tissue morphology, makes Sus scrofa not only a good research model, but also a potential source of cells for tissue engineering. Cell samples obtained from the pig donor, could be influenced in vitro, in order to become a source of tissue material for xenotransplantation, reconstructive and regenerative medicine. Significant amounts of data point to especially major similarities in pig and human reproductive systems. Because of that, particular scientific focus is centered on research concerning porcine COCs, theca and granulosa cells in primary cultures. One of the aspects of the reproductive process, that is still largely undiscovered, is the interaction between preimplantation blastocyst and maternal uterine tissues. In this study, we used molecular analysis techniques, such as RT-qPCR and immunocytochemistry, to analyze the expression and distribution of cytokeratin 18 and panCytokeratins 8, 18 and 19 and vimentin in porcine luminal endometrial epithelial cells, coupled with analysis of their behavior in RTCA. The results have confirmed the presence of epithelial, as well as stromal cell markers in the cells, varying in levels at different stages of culture. They have also given insight into the modes of proliferation and differentiation of studied cells in in vitro culture, as well as providing additional proof for the possible mesenchymal transdifferentiation of epithelial cells.

Surface and swelling properties of mucoadhesive blends and their ability to release fluconazole in a mucin environment.

The aim of this study is to characterize the matrices for the controlled release of fluconazole and to expand the knowledge of their physicochemical properties that influence the process of mucoadhesion. Polymeric carriers of fluconazole were prepared using the following mucoadhesive polymers: Carbopol 974 P NF, Noveon AA-1, HPMC, HEC, chitosan and film-forming polymer Kollidon VA 64. The potential mucoadhesive properties of the polymers and their blends were evaluated by measuring the wettability and then calculating the surface free energy defined by OWRK and vOCG models, determining the polar and dispersion forces, spreading coefficients and work of adhesion of polymers and their blends with fluconazole in the form of tablets. Prepared tablets were characterized by swelling capacity and in vitro drug release to estimate the amount of fluconazole release from selected polymer blends. The study of drug release from selected blends both in simulated saliva fluid (pH = 6.8) and in simulated vaginal fluid (pH = 4.2) containing mucin confirmed the ability of polymeric carriers to continuously deliver drug over a period of about 8 h.

Interaction of polyhedral oligomeric silsesquioxanes and dipalmitoylphosphatidylcholine at the air/water interface: Thermodynamic and rheological study.

Polyhedral oligomeric silsesquioxanes (POSS) derivatives containing open silsesquioxane cage bear great potential for biomedical applications and therefore their lateral interactions with phospholipids, major biomembranes and drug vehicles constituent, should be studied in detail. That is why the properties of surface films by two POSS-derivatives, POSS-polyethylene glycol (POSS-PEG) and POSS-perfluoroalkyl (POSS-OFP), pure and in presence of 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) were studied using Langmuir surface balance. Side chains of opposite nature (PEG is hydrophilic; OFP is hydrophobic) were selected, so that to evaluate their impact on polymers' surface properties. Two types of measurements were performed: (i) the miscibility of POSS-derivatives with DPPC was evaluated via thermodynamic analysis of the surface pressure (π)-area (A) isotherms and (ii) the dilatational rheology of selected POSS-polymer containing films was studied by the stress relaxation method. Fourier transformation analysis of the relaxation transients allows to access films' dynamic interfacial properties in broad frequency range (10-5-1Hz). Film morphology was monitored with Brewster Angle Microscopy. PEG moiety enabled POSS-PEG to stably incorporate in DPPC films, modifying their equilibrium and dynamic properties. In contrast OFP chains excluded from interactions with other molecules and diminished PEG-OFP amphiphilicity. Therefore at high packing densities (π≥25mN/m) PEG-OFP was expelled from the air/water interface in DPPC/PEG-OFP mixtures, and the binary films equilibrium and dynamic surface properties were determined primarily by DPPC. Thus the choice of POSS side chains can play key role in biomedical applications depending on whether strong or weak incorporation of POSS-polymers in lipid environment is aimed for.

Surface properties and surface free energy of cellulosic etc mucoadhesive polymers.

The paper presents the sorption and wettability properties for several mucoadhesive polymers (Carbopol 974P NF (carbomer polymer; carboxy polymethylene), Noveon AA-1, (polycarbophil; acrylic acid polymer crosslinked with divinyl glycol) HPMC (hypromellose; cellulose 2-hydroxyethyl methyl ester) and HEC (cellulose 2-hydroxyethyl ether) and a film-forming polymer Kollidon VA 64 (polyvinylpyrrolidone-vinyl acetate copolymer)) commonly used in controlled drug delivery systems. Moreover, the surface energy of powders was determined using the data obtained according to the three types of experimental investigation. The contact angle measurements for powders were performed according to the Washburn method and using the capillary rise technique. Whereas the sessile drop method was performed on the compressed discs of mucoadhesive polymers. For the surface characterization the IGC technique was also applied. The results obtained by different methods, for both: wettability and surface energies, were compared and correlated. The presented study showed significant differences in the morphology and surface properties of mucoadhesion polymers considered. It was confirmed that for the accurate quantification of the free surface energy (and its components), for mucoadhesive polymers considered, not only the IGC in finite concentration, but also the Washburn method should be used.

The wettability and swelling of selected mucoadhesive polymers in simulated saliva and vaginal fluids.

The surface properties play a particularly important role in the mucoadhesive drug delivery systems. In these formulations, the adsorption of polymer matrix to mucous membrane is limited by the wetting and swelling process of the polymer structure. Hence, the performance of mucoadhesive drug delivery systems made of polymeric materials depends on multiple factors, such as contact angle, surface free energy and water absorption rate. The aim of our study was to analyze the effect of model saliva and vaginal fluids on the wetting properties of selected mucoadhesive (Carbopol 974P NF, Noveon AA-1, HEC) and film-forming (Kollidon VA 64) polymers as well as their blends at the weight ratio 1:1 and 1:1:1, prepared in the form of discs. Surface properties of the discs were determined by measurements of advancing contact angle on the surface of polymers and their blends using the sessile drop method. The surface energy was determined by the OWRK method. Additionally, the mass swelling factor and hydration percentage of examined polymers and their blends in simulated biological fluids were evaluated.

Rare variations of hepatic arteries in association with variable origin of gastroduodenal artery found in multidetector computed tomography angiography.

Three rare anatomical variations were found during study on hepatic arterial vascularisation in multidetector computed tomography angiography. In the first described variation the common hepatic artery (CHA) arises from the celiac trunk (CTr) and supplies right hepatic lobe. The left lobe of the liver is supplied by aberrant left hepatic artery originating as a common trunk with the left gastric artery and the splenic artery. This variation may correspond to the type 2 in Michels' classification coexisting with one of three possible patterns of the CTr division (when the CHA is the first branch of the CTr and the gastrosplenic trunk is the second one). The second variation corresponds to the very early bifurcation of the CHA arising from the CTr. Both, the right and left hepatic arteries originate separately from the CTr. The gastroduodenal artery (GDA) originates from the left hepatic artery. It may be regarded as the variation of most common type 1 according to Michels. In the third case the CHA gives raise to the GDA and terminates as the right hepatic artery supplying the right lobe of the liver only. The proper hepatic artery is missing and the left hepatic artery arises from the GDA. This variation does not correspond to any types of Michels' classification.