The effects of the low-temperature plasma exposure, gg irradiation, and combined γ irradiation and plasma exposure on the structure and surface properties of thin films based on polylactic acid (PLA) are studied. Films are prepared by the solvent casting method. It is shown that films based on polylactic acid have topographically different sides: a smoother inner side and an embossed outer one. PLA films have properties close to hydrophobic ones, with a contact angle in the range of 70°–73° regardless of the surface side. They belong to weakly polar materials. The combined effect of plasma and gg irradiation slightly changes the surface topography. The effect of low-temperature plasma on the surface of the films leads to a decrease in the contact angle by 13°–55° (9–11%) and an increase in the surface energy due to the polar component. The results of in vivo experiments on rabbits are presented. Biomicroscopy, optical coherence tomography, and morphological and electron microscopic examination of the cornea after implantation of the initial and radiation- and plasma-treated films show that implantation of the films in the anterior chamber is not accompanied by a pronounced inflammatory reaction and increased intraocular pressure, while maintaining the morphological structure of the cornea almost unchanged.

Coronary artery disease (CAD) affects every fifth person in the world. The gold-standard treatment for CAD is stent implantation, however, the existing therapy is not sufficient. In recent years, titanium oxynitride (TiOxNy) coatings on bare metal stents (BMSs) attracted the attention of many researchers around the world due to their promising results and improved surface properties. However, good coating adhesion and coverage of the inner surface in stent applications is still a challenging task. Moreover, enhanced corrosion resistance and durability over a longer period under the influence of an aggressive biological environment is one of the main requirements while developing novel coatings for bare-metal stents. In this work, the titanium oxynitride (TiOxNy) coated stainless steel stents were fabricated by magnetron sputtering and the corrosion behavior of coated and uncoated stents has been studied using immersion, fluid dynamic, and electrochemical corrosion tests. For the first time, the entire stent surface has been used for quantitative corrosion tests on stents. We discuss and compare the in vitro biostability and corrosion behavior of bare stainless steel (316L) and titanium oxynitride films (TiOxNy) coated stents.TiOxNy coatings provide valuable stability to the BMS against harsh environments or conditions. The coated stents are remarkably more stable when compared with the reference uncoated stents (316L BMS), regardless of the ratio of O-2 and N-2. The variation of stent coating parameters is still possible to get more anticorrosive and biostable behavior; therefore, the results could provide the basis for further research.

To determine the effect of intracameral implantation of polylactic acid (PLA) films modified in low-temperature atmospheric pressure plasma on the course of in vivo-induced bullous keratopathy (BK).

Titanium oxynitride (TiOxNy) coatings increase the bio- and hemocompatibility of stainless steel and Co-Cr vascular stents, possibly by directly releasing NO. Herein, to examine the applicability of this approach to nitinol (NiTi) devices, we coated NiTi samples with TiOx or TiOxNy by reactive magnetron sputtering using different reaction gas compositions and bias voltages. One side of the samples was preliminarily abraded, while the other remained in its original state. Samples morphology, composition and structure were studied by atomic force microscopy (AFM), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE SEM). We investigated how various types of TiOx and TiOxNy coatings interact with EA.hy926 endothelial cells. None of the tested samples exhibited cytotoxicity, and an N2:O2 ratio of 3:1 regardless of the bias voltage was found to be optimal for NO production and cell adhesion, spreading, and viability, which was ascribed to a cumulative positive effect of the composition and nanoroughness of TiOxNy coatings formed under these conditions. Thus, the deposition of TiOxNy coatings was concluded to be a promising strategy of increasing the biocompatibility of NiTi stents.

The influence of radio-frequency (RF) magnetron sputter deposition conditions (RF power discharge density, working gas atmosphere, deposition time, and electrical substrate bias) on the properties (microstructure, texture, Ca/P ratio) of nanocomposite calcium-phosphate (CaP) coatings has been reported. A phenomenological model was developed to explain the formation of the RF magnetron sputter-deposited hydroxyapatite (HA) coating depending on the various deposition conditions. In the initial deposition stages, a nanocrystalline or quasi-amorphous CaP layer is formed. As both the film thickness and temperature gradient across the film thickness increased, the crystallisation of the HA phase occurred, which led to the formation of the fibre (002) texture in the films. The increase in the coating thickness also resulted in an increase in the grain size and a decrease in the residual microstress. The cross-section of the coating revealed a polycrystalline fibre structure with wedge-shaped columns. The addition of water vapour to an Ar atmosphere allowed to restore the hydroxyl groups in the composition of the HA coatings. The topography of the CaP coating surface that had irregular grains with different form and shape grown out of the coating plane was established, which extended the well-known structural zone models (Thornton, Monsieur, Movchan and Demchishin, Anders, etc.) and was formed both at a relatively low substrate temperature of 160-200 degrees C and RF power level when the substrate was bombarded with positive ions with an energy of similar to 100 eV, regardless of the working gas atmosphere used (argon or oxygen), resulting in a the growth of a coating with a preferably amorphous or nanocrystalline structure.

Cardiovascular diseases are the most distributed cause of death worldwide. Stenting of arteries as a percutaneous transluminal angioplasty procedure became a promising minimally invasive therapy based on re-opening narrowed arteries by stent insertion. In order to improve and optimize this method, many research groups are focusing on designing new or improving existent stents. Since the beginning of the stent development in 1986, starting with bare-metal stents (BMS), these devices have been continuously enhanced by applying new materials, developing stent coatings based on inorganic and organic compounds including drugs, nanoparticles or biological components such as genes and cells, as well as adapting stent designs with different fabrication technologies. Drug eluting stents (DES) have been developed to overcome the main shortcomings of BMS or coated stents. Coatings are mainly applied to control biocompatibility, degradation rate, protein adsorption, and allow adequate endothelialization in order to ensure better clinical outcome of BMS, reducing restenosis and thrombosis. As coating materials (i) organic polymers: polyurethanes, poly(ε-caprolactone), styrene-b-isobutylene-b-styrene, polyhydroxybutyrates, poly(lactide-co-glycolide), and phosphoryl choline; (ii) biological components: vascular endothelial growth factor (VEGF) and anti-CD34 antibody and (iii) inorganic coatings: noble metals, wide class of oxides, nitrides, silicide and carbide, hydroxyapatite, diamond-like carbon, and others are used. DES were developed to reduce the tissue hyperplasia and in-stent restenosis utilizing antiproliferative substances like paclitaxel, limus (siro-, zotaro-, evero-, bio-, amphi-, tacro-limus), ABT-578, tyrphostin AGL-2043, genes, etc. The innovative solutions aim at overcoming the main limitations of the stent technology, such as in-stent restenosis and stent thrombosis, while maintaining the prime requirements on biocompatibility, biodegradability, and mechanical behavior. This paper provides an overview of the existing stent types, their functionality, materials, and manufacturing conditions demonstrating the still huge potential for the development of promising stent solutions.

The paper presents the results of the study of the effect of ratios of reactive gases N2 and O2 on the structural phase state and the mechanical properties of nitrogen-containing titanium dioxide coatings obtained by reactive magnetron sputtering on the surface of AISI 304 stainless steel. According to the results of the X-ray phase analysis, the coatings contain titanium dioxide in the form of anatase, rutile and a small amount of brookite. It was found that with an increase in the nitrogen content in the working atmosphere, the volume fraction of anatase and rutile increases. An increase in the nitrogen content in the gas atmosphere leads to the formation of a quasihomogeneous surface texture with a less pronounced block structure. Based on the results of nanoindentation, it can be assumed that the formation of a quasihomogeneous texture can cause a decrease in the physicomechanical parameters of the coatings. It was established that the structure, phase composition, and mechanical properties of the coatings depend on the gas ratio N2/O2 in theт negative bias mode (Ubias = −150 V).

This paper presents data on the effects of steam sterilization on the properties of thin films based on polylactic acid. It has been established that thin films based on polylactic acid and poured from solutions of 10, 20, and 30 g have two topographically different sides. One side (internal) has a more prominent surface. The other side (external) has a smooth surface. It is reflected in the roughness parameters. R a of the internal side varies from 0.01 to 0.018 μm. R a of the external side is 0.17–0.4 μm. The average roughness increases from 0.17 to 0.4 μm with an increase in the mass of the solution poured into films. Sterilization contributes to a change in the surface of the polylactic acid films and makes their profile more prominent. This leads to a significant increase in the roughness of both sides by more than 5 times. In addition, it was found that thin polylactic acid films have hydrophobic (θ = 80°) properties. Steam sterilization reduces the wetting angle by 14°–15° (17–18%) and increases the surface energy values to a greater extent owing to the polar component. These changes increase the hydrophilicity of the studied material.

One of the current areas of medical materials science is the formation of ultrathin coatings on the surface of implants. Among the many types of coating used in vascular surgery, binary and ternary titanium compounds have good prospects due to their high bio- and hemocompatibility. The properties of the coating based on films of nitrogen-containing titanium oxide (titanium oxynitride), applied by reactive magnetron sputtering (RMS), was studied. While problems of establishing and maintaining the necessary spraying mode is relevant for the RMS technique. The cytotoxicity of the titanium oxy nitride compounds obtained under various modes of functioning of RMS on endothelial cells line EA.hy 926 was the aim of this report. It was showed that the levels of nitric oxide (NO) production by EA.hy 926 cell line on Day 1 and Day 5 growth under the different samples of nitinol treated with different RMS modes was comparable to control. It was no obtained cytotoxic effect of the nitrogen-containing coatings of titanium oxide obtained by various modes of RMS on EA.hy 926 cell line. While was observed reduced levels of NO production by EA.hy 926 cell line on Day 3.

The structure and properties of titanium oxide films deposited by reactive magnetron sputtering are studied. The results of the study of thin films using IR and Raman spectra show that the presence of a two-phase TiO2 structure and the formation of an N-O bond when nitrogen is introduced without the formation of titanium nitride (TiN), and may also indirectly indicate the presence of nitrogen oxide compounds in the film. It was found that the structure, element and phase composition of coatings depend on the value of the oxygen / nitrogen ratio in the composition of the reactive gas, as well as on the value of the negative displacement on the substrate. An increase in the proportion of nitrogen leads to a decrease in the spray rate. The obtained materials have the structure of anatase and rutile. The x-ray photoelectron spectroscopy method shows the presence of nitrogen (N) in The TiO2 lattice. In samples doped with nitrogen, a band appears in the Raman scattering spectra at 1048 cm-1 associated with the presence of nitrogen in TiO2. The elemental composition was also studied using an optical emission spectrometer of a glow discharge. Analysis of molecular bonding in the coatings was carried out using Fourier transform infrared spectroscopy. To measure Raman micro-spectra, a device developed at Fraunhofer IKTS-MD was used, consisting of a unit containing an inverted ZEISS optical microscope, Axiovert, and an iHR550 spectrometer with a cooled detector (Horiba, Jobin Yvon Inc.), A laser with a wavelength of 632.8 nm was used to excite the oscillations. Optical characteristics of coatings were studied on the spectral ellipsometric complex "Эллипс-1891 САГ" at a fixed angle of analysis of 70° in the range of wavelengths λ = 250-1000 nm.

Information is given on the effect of plasma surface modification and sterilization processes on the optical characteristics of a track membrane (TM) made of polyethylene terephthalate (PET). TMs were obtained by irradiating PET with a 40Ar + 8 ion beam and etching in a 1.5 M NaOH solution. Modification of TMs were carried out by low-temperature plasma, sterilization by autoclaving and gamma radiation. TMs from PET are characterized by a relatively low transmittance and refractive power, which is associated with the appearance of heterogeneities in the structure of PET, as well as the crystalline structure of the polymer. Exposure to plasma and sterilization reduced the transmittance of TM associated with an increase in crystallinity and the formation of membrane artifacts.

The influence of modification by low-temperature atmospheric-pressure plasma and steam sterilization on the properties of track membranes based on polyethylene terephthalate is studied. It is found that the action of hot steam under pressure changes the topography of the surface of the membranes with the formation of artifacts in the form of large oval-shaped protrusions with a height of 300–400 nm and a density of up to 0.007 protrusions/μm2 on the surface, increases the surface roughness by 40% and the wetting angle by 9°–18° for the initial membranes and by 36.8°–39.6° for the membranes modified in plasma, and decreases their surface energy to the initial value of 33 mJ/m2. Despite the morphological and structural changes in the surface, sterilization by hot steam under pressure does not lead to any noticeable change in the surface charge and ζ potential of the track membranes. Hot steam under pressure does not promote further crystallization of the membrane, keeping the polymer with a crystalline phase of 40–42%. Thus, to preserve the properties acquired by the membrane after the plasma treatment, it is necessary to search for a different sterilization method (gamma radiation, ethylene oxide sterilization).

Effect of plasma modification of surface and sterilization processes on optical characteristics of a polyethylene terephthalate (PET) track membrane (TM) is studied. The TMs are fabricated with the aid of irradiation of PET using 40 Ar +8 ion beam and etching in a 1.5-M solution of NaOH. The TMs are modified using low temperature plasma and sterilized with the aid of autoclave treatment and gamma irradiation. The PET TMs exhibit low transmittance and refractivity due to formation of structural inhomogeneities and polymer crystal structure. The effect of plasma and sterilization leads to a decrease in the TM transmittance owing to an increase in the degree of crystallinity and formation of membrane artifacts.

The structural features of N-doped titanium dioxide (N-TiO2) thin films deposited via reactive magnetron sputtering system with different nitrogen to oxygen ratio are analyzed. Bias voltage was used as a significant parameter involved in the deposition process. Grown films have two-phase structure consisting of anatase and ruffle mixture. The analysis of structure and morphology of the films by SEM, TEM, XRD, FTIR and XPS techniques showed the changing of anatase to ruffle ratio and grain size reduction in N-TiO2 thin films with increase of nitrogen content in the working gas at simultaneous bias applying. Nitrogen atoms in oxide form are located at the crystallites boundaries and this 2D quasi-layer of NOx species limits the epitaxial growth of TiO2 crystallites during film formation.

A crucial property for implants is their biocompatibility. To ensure biocompatibility, thin coatings of hydroxyapatite (HA) are deposited on the actual implant. In this study, we investigate the effects of the addition of silicate anions to the structure of hydroxyapatite coatings on their adhesion strength via a scratch test and ab initio calculations. We find that both the grain size and adhesion strength decrease with the increase in the silicon content in the HA coating (SiHA). The increase in the silicon content to 1.2 % in the HA coating leads to a decrease in the average crystallite size from 28 to 21 nm, and in the case of 4.6 %, it leads to the formation of an amorphous or nanocrystalline film. The decreases in the grain and crystallite sizes lead to peeling and destruction of the coating from the titanium substrate at lower loads. Further, our ab initio simulations demonstrate an increased number of molecular bonds at the amorphous SiHA-TiO2 interface. However, the experimental results revealed that the structure and grain size have more pronounced effects on the adhesion strength of the coatings. In conclusion, based on the results of the ab initio simulations and the experimental results, we suggest that the presence of Si in the form of silicate ions in the HA coating has a significant impact on the structure, grain size, and number of molecular bonds at the interface and on the adhesion strength of the SiHA coating to the titanium substrate.

The report is directed to nanostructured hydroxyapatite (HA) electrically functionalized costing aimed to enhance biocompatibility of the HA originated implants. The reader will be guided from necessity and prerequisites for HA electrical functionalization to its computed designing, characterization technique, fabrication, and biological properties.

A study on the use of track etched membranes (TM) based on the polyethylene terephthalate (PET), including those modified with cold plasma, followed by layering of prenatal stromal cell (PSC) culture on the material surface in vitro in the surgical treatment of a bullous keratopathy (BK) of the cornea has been conducted. The study was conducted on 16 Sylvilagus bachmani rabbits, which after BK modelling were divided into 4 groups: the 1st group was a control group of 4 animals (4 eyes); the 2nd group was a group of 4 animals (4 eyes) which were implanted by TM; the 3rd group was a group of 4 animals (4 eyes) which were implanted by TM with cells; the 4th group was a group of 4 animals (4 eyes) which were implanted by plasma modified TM with cells. TM was obtained by irradiating PET with Ar-40(+8) ions and subsequent chemical etching. Eyes were enucleated for histological examination after 8 weeks from the start of the experiment. As a result of the research, it was found that the implantation of TM with a preliminary layering of human PSC promotes the growth of the fibroblast population in the cornea stroma and forming of the leukocyte (lymphocytic and eosinophilic-basophilic) infiltration compared with the implantation of TM without a cellular component. In addition the implantation of TM contributes to a twofold decrease in the induced by BK cornea edema.

The calcium phosphate coating was provided onto the titanium substrate because of the nanoarc coatings technology. Both surface morphology and electrical charge of the coating were measured at the nano/micro-scaled lateral resolution. The negative electrical potential was typical for sockets, however the positive one to the peaks of the roughness. The cells were mainly attached at the negatively charged sockets. The cells expressed both osteocalcin and alkaline phosphatase that are the osteoblastic molecular markers.

The aim of the research is to study the possibility of using track-etched membrane, including track-etched membranes modified with cold plasma, followed by layering prenatal stem cells (PSC) on the material surface in surgical treatment of bullous keratopathy (BK). Materials and methods. The track membranes made of polyethylene terephthalate were obtained by irradiating the polymeric film with the 40Ar+8ion beams and by chemical etching. The study was conducted on 16 rabbits (Sylvilagus bachmani), which after BK modelling were divided into 4 groups: the 1st group was a control group of 4 animals (4 eyes); the 2nd group was a group of 4 animals (4 eyes) into which were implanted TM; the 3rd group was a group of 4 animals (4 eyes) into which were implanted TM with PSC; the 4th group was a group of 4 animals (4 eyes) into which were implanted plasma modified TM with PSC. TM was obtained by irradiating the PET film with 40Ar + 8 ions and subsequent chemical etching. The eyes were enucleated for histological examination after 8 weeks from the start of the experiment. Results. As a result of the research, it was found that the implantation of TM with a preliminary layeringof human PSC promotes the growth of the fibroblast population in the cornea stroma and intensifies leukocyte (lymphocytes and eosinophilic granulocytes) infiltration as opposed to the implantation of PET TM without a cellular component. In addition, the implantation of TM contributes to a twofold decrease in the cornea edema induced by BK. Modification of TM with cold plasma did not affect the studied histomorphometric parameters. Conclusion. The implantation of TM based on PET during bullous keratopathy contributed to the development of the productive phase of infiltrative inflammation in the cornea of the eye. Pre-layering of human PSC reduced the severity of destructive changes in the rabbit cornea after BK modeling. The modification of TM by cold plasma did not affect the studied histomorphometric parameters.