română ȘTEFANIA MARIN, MĂDĂLINA GEORGIANA ALBU KAYA, GEORGETA VOICU, GRAȚIELA TEODORA TIHAN
Abstract
In this work the attention was focused on the superior properties of polyvinylalcohol – collagen hydrogels.Burns leads to exposure of the deeper layers of skin proportional to the size and depth of the wound. The pH level in the wound bed is a key parameter for assessing indicative of wound healing problems and temperature the same. The lower temperatures can stop the activity of the cells involved in the healing process.The aim of this study was to characterize hydrogels previously obtained in terms of pH and temperature sensitivity in order to choose the most appropriate formulation that could be used for burn healing. Hydrogels were made from collagen gel with initial concentration of 2.85% and polyvinyl alcohol having a molecular weight of 60 000 Da. The hydrogels obtained were lyophilized in order to be analyzed by microstructural appearance (SEM images) and also from the point of view of their sensitivity to different values of pH and temperature. Based on result obtained it was demonstrated that the sample with equal proportions of collagen and polyvinyl alcohol shows that it has the required properties in order to be used as a dressing in healing burns. This hydrogel will be basic support for new smart dressings with included nanoparticles, with targeted applications in medicine.
Keywords
composite, collagen, polyvinyl alcohol, hydrogels, pH, temperature
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Year
2017
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Issue
47 (1)
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Pages
78-83
GHEORGHE ION POPESCU, OLIVERA LUPESCU , MIHAIL NAGEA, DAN CORNECI
Abstract
Fibrin-based sealants are mainly based on fibrinogen and thrombin; in the presence of even small amounts of Factor XIII and calcium, fibrinogen is polymerised by thrombin into insoluble fibrin, which organises as a network with multiple functions: it has a major role into the coagulation cascade and it also enhance wound healing, thus playing a key role in human body reaction to any type of aggression, including the surgical procedures. Due to their properties, fibrin-derived materials have been intensively studied and enhanced, so that they nowadays represent a group of great interest for many medical fields. One of the most frequently performed orthopaedic procedures, hip arthroplasty is, in the same time, considerably invasive upon homeostasis, especially due to bleeding, which can lead to dramatic outcome of the patients, as well as upon the soft tissues, with different healing properties. Intensive studies have been thus performed in order to find materials able to diminish these effects, fibrin-based sealants proving themselves as able to fulfil these requirements. This paper reflects the clinical experience of using a Fibrin-based sealant in major orthopaedic procedures, revealing the advantages of using this type of materials for the outcome of the patients.
Keywords
fibrin sealants, hip arthroplasty, haemostatic, fibrin glue
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Year
2017
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Issue
47 (1)
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Pages
84-90
S.CAVALU, C. RAŢIU
Abstract
PMMA (poly methyl methacrylate)- based biomaterials still have many shortcomings. Over the last two decades, additives have been developed to address these shortcomings. In our approach, acrylic bone cements were prepared by reinforcing commercial PMMA-based bone cements with 5% Mg3Al2(SiO4)3. Structural investigation performed by ATR FTIR (Atenuated Total Reflectance Fourier Transform Infrared Spectroscopy) spectroscopy and XRD (X-Rays Difraction) demonstrated the inclusion of the crystalline phase in polymeric matrix. The SEM (Scanning Electron Microscopy) images (surface and fracture) revealed that the addition of 5% Mg3Al2(SiO4)3 create a porous structure in PMMA matrix, and facilitate the hydroxyapatite formation in vitro. The biocompatibility tests using human fibroblasts and SEM micrographs revealed the cells attachment and spreading on the surface of both specimens (with and without magnesium aluminosilicate). The fibroblasts showed a wide variety of shapes after 24 hours incubation: spread multipolar or round, as well as spindle shaped or elongated cells. No significant cytotoxic effect was noticed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction); moreover, the proliferation rate seems to be favored by the presence of 5% Mg3Al2(SiO4)3.
Keywords
PMMA bone cement, magnesium aluminosilicate, FTIR, XRD, SEM, biocompatibility
XIAONIU YU, CHUNXIANG QIAN, LINZHU SUN, ZHIHAI HE, WEI LI, LINGJIE WU
Abstract
Magnesium phosphates can be prepared by microbial induced deposition, and bio-grouting and stirring processes are used to bind loose sand particles. The result shows that loose sand particles can well be cemented by stirring method. However, loose particles are not bound by pumping method. The X-ray diffraction (XRD) of the precipitated slurry indicates that the main component is a mixture of hydrated magnesium phosphate. Energy dispersive spectrometer (EDS) displays that elements of sandstones are mainly C, Si, O, P, Mg, Na and Cl. The average compressive strength and porosity of sandstones are 0.99±0.3MPa and 26.3±0.5%, respectively. Scanning electron microscope (SEM) shows that the cementation material in sandstones is flake nano-clusters with the size in the range of 0.5-1.5µm. Transmission electron microscopy (TEM) further indicates that a single nanoparticle is like irregular sheet in morphology, and the size of the cementitious material is in the range of 200-500 nm.
Keywords
magnesium phosphates; pumping method; stirring method; sandstone; compressive strength; Transmission Electron Microscopy
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Year
2017
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Issue
47 (2)
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Pages
143-146
A. PASCU, E.M. STANCIU, I. C. ROATĂ, I. HULKA, D. UȚU, I. MAIOR
Abstract
The paper presents the influence of the deposition process parameters in order to obtain dense and no major defect biocompatible alloys based on Inconel 718 hard coatings deposited on AISI 5140 carbon steel substrate using laser cladding method. Moreover, the cladded coating properties under optimal manufacturing conditions in terms of microhardness and tribological behaviour were improved by surface solar energy irradiation. The microstructure of the Inconel 718 coating before and after solar heat treatment was investigated by scanning electron microscopy (SEM) and the sliding wear resistance was determined by pin-on-disk method (POD).
Keywords
biocompatible coatings, laser cladding, solar heat treatment, wear resistance