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Polyetheretherketone (PEEK), due to its excellent mechanical and physico-chemical parameters, is an attractive substitute for hard tissues in orthopedic applications. However, PEEK is hydrophobic and lacks surface-active functional groups promoting cell adhesion. Therefore, the PEEK surface must be modified in order to improve its cytocompatibility. In this work, extreme ultraviolet (EUV) radiation and two low-temperature, EUV induced, oxygen and nitrogen plasmas were used for surface modification of polyetheretherketone. Polymer samples were irradiated with 100, 150, and 200 pulses at a 10 Hz repetition rate. The physical and chemical properties of EUV and plasma modified PEEK surfaces, such as changes of the surface topography, chemical composition, and wettability, were examined using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and goniometry. The human osteoblast-like MG63 cells were used for the analysis of cell viability and cell adhesion on all modified PEEK surfaces. EUV radiation and two types of plasma treatment led to significant changes in surface topography of PEEK, increasing surface roughness and formation of conical structures. Additionally, significant changes in the chemical composition were found and were manifested with the appearance of new functional groups, incorporation of nitrogen atoms up to ~12.3 at.% (when modified in the presence of nitrogen), and doubling the oxygen content up to ~25.7 at.% (when modified in the presence of oxygen), compared to non-modified PEEK. All chemically and physically changed surfaces demonstrated cyto-compatible and non-cytotoxic properties, an enhancement of MG63 cell adhesion was also observed.

Known techniques for modification of polypropylene membranes (PPm) often require modification of the membrane in its entire volume (i.e. at the manufacturing stage), which may affect its properties. In the present work, the authors proposed a simple method for PPm hydrophilization. The process involves a two-step Fenton-type reaction, with ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent and cumene hydroperoxide (CHP) as a source of free radicals. This hydrogel coating aims to enhance membrane hemocompatible and biocompatible properties. The biggest advantage of the proposed technique is the change of materials' surface properties, without interfering with its internal structure. Microscopic (SEM) and spectroscopic (FTIR-ATR) analyses confirmed the presence of hydrogel coating on PPm surfaces. Additionally, the evaluation of the surface density of the coating showed that the thickness of the coating increases with the reaction time and CHP concentration. The applied coatings significantly increase surface hydrophilicity (contact angle for PPm: 128.58° ± 0.52°, for all modified surfaces <53.31° ± 2.03°). The cytotoxicity test (XTT assay) proved biocompatibility of the PVP coating - cell viability remained above 90% for all variants tested. The modification resulted in a decrease in fibrinogen adsorption (of at least about 16%) and in a number of surface-adhered platelets. The assay evaluating the amount of secreted cell adhesion molecules (ICAM-1) showed a significant reduction (of at least about 50%) in the expression of ICAM-1 for all hydrogel-modified surfaces., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

When evaluating a novel bone substitute material, advanced in vivo testing is an important step in development and safety affirmation. Sheep seems to be a valuable model for human bone turnover and remodeling activity. The experimental material composed with the stem cells is an advanced therapy medicinal product (acc. to EC Regulation 1394/2007). Our research focuses on histological differences in bone formation (guided bone regeneration--GBR) in sheep maxillas after implantation of the new chitosan/tricalcium phosphate/alginate (CH/TCP/Alg) biomaterial in comparison to the commercially available xenogenic bone graft and a/m enhanced with the stem cells isolated from the adipose tissue. Twelve adult female sheep of BCP synthetic line, weighing 60-70 kg were used for the study. The 11 mm diameter defects in maxilla bone were prepared with a trephine bur under general anesthesia and then filled with the bone substitute materials: CH/TCP/Alg, BioOss Collagen, Geistlich AG (BO), CH/TCP/Alg composed with the stem cells (CH/S) or left just with the blood clot (BC). Inbreeding cycle of the animals terminated at 4 months after surgery. Dissected specimens of the maxilla were evaluated histologically and preliminary under microtomography. Histological evaluation showed early new bone formation observed around the experimental biomaterial and commercially available BO. There were no features of purulent inflammation and necrosis, or granulomatous inflammation. Microscopic examination after 4 months following the surgery revealed trabecular bone formation around chitosan based bone graft and xenogenic material with no significant inflammatory response. Different results--no bone recreation were observed for the negative control (BC). In conclusion, the tested materials (CH/TCP/Alg and BO) showed a high degree of biocompatibility and some osteoconductivity in comparison with the control group. Although the handiness, granules size and setting time of CHffCP/Alg may be refined for future clinical tests. The relevant beneficial influence of using the adipose derived stem cells in GBR was not confirmed in this model.

Polymeric biomaterials are being widely used for the treatment of various traumata, diseases and defects in human beings due to ease in their synthesis. As biomaterials have direct interaction with the extracellular environment in the biological world, biocompatibility is a topic of great significance. The introduction or enhancement of biocompatibility in certain polymers is still a challenge to overcome. Polymer biocompatibility can be controlled by surface modification. Various physical and chemical methods (e.g., chemical and plasma treatment, ion implantation, and ultraviolet irradiation etc.) are in use or being developed for the modification of polymer surfaces. However an important limitation in their employment is the alteration of bulk material. Different surface and bulk properties of biomaterials are often desirable for biomedical applications. Because extreme ultraviolet (EUV) radiation penetration is quite limited even in low density mediums, it could be possible to use it for surface modification without influencing the bulk material. This article reviews the degree of biocompatibility of different polymeric biomaterials being currently employed in various biomedical applications, the surface properties required to be modified for biocompatibility control, plasma and laser ablation based surface modification techniques, and research studies indicating possible use of EUV for enhancing biocompatibility., (© 2013 Wiley Periodicals, Inc.)

Over the last few years, alloplastic bone substitute materials are raising much interest as an alternative to autologic transplants and xenogenic materials especially in oral surgery. These non-immunogenic and completely resorbable biomaterials are becoming the basis for complete and predictable guided bone regeneration in many cases. The objective of our research was to evaluate the dynamics of bone formation in rats' skulls after implantation of the new chitosan/tricalcium phosphate/alginate biomaterial in comparison to the commercially available alloplastic bone graft. A total of 45 adult male rats weighing 300-400 g were used for the study. The 85-mm-diameter defects in calvaria bone were prepared with a trephine bur, and then filled with the bone substitute materials: chitosan/tricalcium phosphate/alginate or easy-graft Classic (Degradable Solutions AG) (EA) or left just with the blood clot. Animals were sacrificed at 1 and 3 months for histological, histomorphometrical and micro-tomographic evaluations. Histological evaluation at 1 month showed early new bone formation, observed around the experimental biomaterial (CH/TCP/Alg). There were no features of purulent inflammation and necrosis or granulomatous inflammation. Microscopic examination after 3 months following the surgery revealed trabecular bone formation around chitosan-based bone graft with no significant inflammatory response. Less satisfactory and differing results were observed for the commercially available EA and control blood clot. The tested material (chitosan) showed a high degree of biocompatibility and osteoconductivity in comparison with the control groups. Additionally, it seemed to be a "user-friendly" material for oral surgeons.

In this paper the authors present a simple method of coating polyurethane (PU) surface with poly(vinyl pirrolidone) (PVP) hydrogel. The hydrogel-coated materials were designed for use in biomedical applications, especially in blood-contacting devices. The coating is formed due to free radical macromolecular grafting-crosslinking. Polymer surface was first immersed in an organic solution containing radical source: cumene hydroperoxide (CHP) with an addition of a branching and anchoring agent: ethylene glycol dimethylacrylate (EGDMA). In the second step, the substrate was immersed in a water solution containing given concentration of PVP and Fe(2+). The novelty of the process consists in the fact that free radicals are formed mostly at the polymer/solution interface, what assures high grafting efficiency together with the formation of covalent bonds between polymer substrate and modifying layer. The process was optimized for reagents concentrations. The coating properties: thickness and the swelling ratio were strongly influenced by CHP, Fe(2+), PVP and EGMDA concentrations. The chemical composition of the surface analyzed with FTIR-ATR spectroscopy confirmed the presence of PVP coating. In vitro biocompatibility tests with L929 fibroblasts confirmed non-cytotoxicity of the coatings. Hydrogel coating significantly improved polyurethane hemocompatibility. Studies with human whole blood revealed that both, the platelet consumption and the level of platelet activation were as low as for negative control., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Alloplastic bone substitute materials are raising some more interest as an alternative for autologic transplants and xenogenic materials especially in oral surgery over the last few years. These non-immunogenic and completely resorbable biomaterials are the basis for complete and predictable guided bone regeneration. In the majority of cases, such a material is chosen because of its convenient application by surgeons. The main objective of our project was to design and fabricate an osteoconductive, injectable and readily tolerable by human tissues biomaterial for guided bone regeneration. For this purpose, a self-setting composite consisting of chitosan/tricalcium phosphate microparticles and sodium alginate was made. The material obtained was characterized by microsphere and agglomerate morphology and microstructure. Its features relating to setting time and mechanical properties were precisely investigated. Our material was also evaluated according to PN-EN ISO 10993 Biological evaluation of medical devices, i.e., the in vitro tests for genotoxicity and cytotoxicity were conduced. Then, the following examinations were performed: subchronic systemic toxicity, skin sensitization, irritation and delayed-type hypersensitivity and local effects after implantation. The material tested showed a high degree of cytocompatibility, fulfilled the requirements of International Standards and seemed to be a "user friendly" material for oral surgeons.

Device for in-vitro measurement of static and kinetic friction coefficient of catheter surface was developed. Tribometer was designed and constructed to work with exchangeable counter-faces (polymers, tissue) and various types of tubes, in wet conditions in order to mimic in-vivo process. Thus seven commercially available urethral catheters, made from vinyl polymers, natural latex with silicone coating, all-silicone or hydrogel coated, and one made from polyvinylchloride with polyurethane/polyvinylpyrrolidone hydrogel coating obtained in our laboratory, were tested against three various counter faces: polymethacrylate (organic glass), inner part of porcine aorta and porcine bladder mucosa. Additionally, the hydrophility/hydrophobity of tested catheters was stated via water wetting contact angle measurement. Super-hydrophilic biomaterials revealed low friction on tissue and hydrophobic counter-face; slightly hydrophobic showed higher friction in both cases, while more hydrophobic manifested low friction on tissue but high on hydrophobic polymer. The smoothest friction characteristic was achieved in all cases on tissue counter-faces. The measured values of the static coefficient of friction of catheters on bladder mucosa counter-face were as follows: the highest (0.15) for vinyl and siliconised latex catheters and 3 folds lower (0.05) for all-silicone ones. Hydrogel coated catheters exhibited the lowest static and kinetic friction factors.