Papers by Keyword: Biocompatibility

Abstract: The objective of this study was to compare the cytotoxicity of a domestically-made light-cured orthodontic adhesive to a commercial adhesive, Transbond XT (3M Unitek, USA). An in-house orthodontic adhesive composed of a filler 60-70 weight % and a monomer ratio (BisGMA:TEGDMA) of 6:4 with 0.5% of photoinitiator was mixed. The potential cytotoxic effect of this experimental and a control adhesive was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay according to ISO 10993-5: 2009(E). The L929 cell line was grown in 96-well tissue culture plates (1x10⁵ cells/mm³). Thin cured-resin discs of each material weighing 0.4 gram were prepared and incubated for 1, 3, 5, 7, 14, and 30 days in Dulbecco’s modified Eagle medium (DMEM) at 37°C and 95% humidity with 5% CO₂. The percentage of cell viability was reported by descriptive statistics. The result showed that the cell viability of the experimental adhesive was higher than Transbond XT in all measured periods. The cytotoxicity of both the adhesives gradually decreased with the progression of time. In conclusion, the in-house adhesive showed a good biocompatibility since the first day following polymerization. On the other hand, Transbond XT started with a cytotoxic potential, then, turned to be non-cytotoxic after 5 days of curing.

Abstract: In the medical industry the medical device sector is a domain dynamic and growing, that involved important efforts performance for imposing new material to support the development of new products. Manufacturers of medical devices for single use, are constantly looking for new products and new materials to expand their capabilities.

Abstract: In this paper, a novel technique for modification of PEDOT:PSS surface by the arginine-glycine-aspartic (RGD) acid, using a bifunctional photolinker sulfosuccinimidyl 6-(4’-azido-2’-nitrophenylamino) hexanoate (sulfo-SANPAH), is presented. The technique is based on the UV light initialized immobilization of the photolinker to the surface of the polymer and subsequent link of the RGD peptide to the photolinker via coupling reaction. The aim of this modification is the improvement of the biocompatibility and hydrophilicity of the polymer PEDOT:PSS. To confirm if the process of conjugation of RGD peptide to the surface of the polymer PEDOT:PSS was successful, the contact angle measurement, Fourier transform infrared spectroscopy, Raman spectroscopy and elemental analysis was performed. All of the obtained results indicate the conjugation of RGD peptide to the PEDOT:PSS surface was successful.

Abstract: At present, biomaterials are used in several sectors of medicine such as implant manufacturing, tissue engineering, orthopedic and prosthetic aids, drug delivery systems and many others. The use of biomaterials is increasingly related to the additive manufacturing (AM) of various medical devices and aids. Biomaterials and their use in medicine are important not only in terms of their biocompatibility and direct effect on the human organism, but also in terms of their biodegradability, processability and non-toxicity to the environment either during their production or during their processing after use. Bioplastics of the type Polylactic acid (PLA) appears to be a suitable biomaterials for use in a variety of medical applications in conjunction with an AM process. For this reason, this article discusses 1) description and use of biomaterials in medical applications 2) AM and biomaterials 3) key properties and uses of PLA bioplastics in medicine and 4) the specific AM of an orthopedic corset made of PLA and its benefits.

Abstract: Polypyrrole (PPy) is an attractive scaffold material for tissue engineering with its non-toxic and electrically conductive properties. There has not been enough information about PPy usage in skin tissue engineering. The aim of this study is to investigate biocompatibility of polyacrilonitrile (PAN)/PPy nanofibrous scaffold for human keratinocytes. PAN/PPy bicomponent nanofibers were prepared by electrospinning, in various PPy concentrations and with carbon nanotube (CNT) incorporation. The average diameter of electrospun nanofibers decreased with increasing PPy concentration. Further, agglomerated CNTs caused beads and disordered parts on the surface of nanofibers. Biocompatibility of these PAN/PPy and PAN/PPy/CNT scaffolds were analyzed in vitro. Both scaffolds provided adhesion and proliferation of keratinocytes. Nanofiber diameter did not significantly influence the morphology of cells. However, with increasing number of cells, cells stayed among nanofibers and this affected their shape and size. In this study, we demonstrated that PAN/PPy and PAN/PPy/CNT scaffolds enabled the growth of keratinocytes, showing their biocompatibility.

Abstract: Metastable β-Ti alloy Ti-35.3Nb-7.3Zr-5.7Ta-0.7O (wt. %) shows properties desirable for use as an implant material. However, very large grains (with the size of 0.5 – 3 mm) negatively affect the strength and fatigue resistance. Combination of cold-swaging and recrystallization annealing is used to refine the microstructure. Microstructure after cold swaging and after annealing is studied using scanning electron microscope by electron back-scatter diffraction measurements. Grain size and texture is determined and homogeneity of deformation inside the grains is discussed. Microhardness maps are measured in the cold-swaged samples. It is found that microhardness and thus also the deformation is higher in the center of each rod however the grains retain their original size. Annealing leads to recrystallization that is complete or nearly complete at the temperatures of 1000°C and more. Annealing at 1000°C for 15 min yields grain size of around 100 μm. This grain size is believed to increase the fatigue performance to satisfactory values.

Abstract: The work is devoted to the discussion of hypotheses that are put forward to explain the processes occurring during ion-plasma treatment of polyurethane. A carbonized layer forms on the surface of the polymer as a result of ion-plasma treatment. However this layer is not even. Wavy relief, the geometric features of which depend on the fluence (the number of ions entering the unit surface of the sample) and the energy of ions, is formed. It is shown that a simple explanation related to material heating and subsequent shrinkage does not allow explaining the cause of the phenomenon. The second hypothesis can be the pressure of the ion flow on the surface of the sample. It causes deformation and subsequent changes in the stress-strain state after the irradiation is stopped. Calculations show that this mechanism cannot explain the formation of the folded relief of the layer. A hypothesis, based on information about a significant material change, is expressed in the article. Polymer chains under ion-plasma treatment are broken into atoms. After striking ions move deep into the material causing the polymer to swell in the near-surface layer. This swelling can cause material to move close to the sample boundary and leads to the formation of a wavy surface.

Abstract: Titanium implants with porous surface arranged orderly were fabricated by micromachining through photolithography and chemical etching. The titanium discs were implanted into the canine mandible alveolar bone for 3 and 21 days, for animal experiments. Neogenetic bone was observed onto porous surface after 7 days‘ implantation. This result allows us to expect application of titanium with porous surface as biomaterials.

Abstract: Ti-based amorphous alloys containing no harmful elements are desired. However, many Ti-based amorphous alloys contain toxic elements such as Al, Ni, V and Be. The presence of toxic elements within amorphous alloys is a concern when they are intended for use as a biomaterial. This problem has steered many researchers toward the development of Ti-based amorphous alloys without toxic elements. Our novel amorphous alloys were developed based on this principle. A series of Ti44Zr10Pd10Cu6+xCo23-xTa7 (x = 0, 4, 8) amorphous alloys were developed for biomedical application. A series of protocol tests were performed to check for biocompatibility and potential use of the novel alloys in humans. First, alloy ingots were alloyed by induction melting and then cast into copper molds. The cast rod was then used as the plasma cathode in a filtered cathodic vacuum arc deposition chamber to coat the 25-nm amorphous alloy thin film on the cover glass slides. These coated cover glass slides were then examined for biocompatibility. Cell proliferation and cell differentiation were investigated using Methylthiazol Tetrazolium assay test and by alkaline phosphatase assay on osteoblast like cells (SaOS-2), respectively. Field emission scanning electron microscopy was performed to evaluate the thin film surface characteristics. The thickness of thin film was analyzed using a Stylus profilometer. An adhesion scratch test was administered to evaluate the thin film adhesive strength and indirect hardness comparison. Electron Dispersive X-ray Spectrometry was performed to study the elemental composition. Lastly, a medical grade Ti-6Al-4V alloy was studied in parallel as a control material. Results indicated that all investigated Ti-based amorphous alloys were non-cytotoxic and were comparable to the Ti-6AL-4V. They also demonstrated an ability to support differentiation of osteoblast like cells. The adhesion and the hardness of the thin films on the substrates were superior to that of Ti-6Al-4V. The results suggested that the novel alloys in this study could be potentially utilized in biomedical applications.

Abstract: Highly-ordered nanoleaf sodium titanate were successfully synthesized on high-purity titanium surface by catalyst oxidation method. Sodium metaborate powder was coated on titanium substrates, heated in an electric furnace at 650°C for 5 hours and then subjected to a water bath rinse. The structure and morphology of oxide coatings were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the fabricated coatings were composed of rutile and sodium titanium, providing the excellent biocompatibility and nanoscale even gap structure between bamboo-shaped sodium titanate. The mechanism about the growth of highly-ordered nanoleaf sodium titanate also discussed in the current work.