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EN
Biocomposite foam scaffolds of poly(ε-caprolactone) (PCL) with different porogenes were producedwith batch foaming technique using supercritical carbon dioxide (scCO2)as a blowing agent. Inperformed experiments composites were prepared from graphene-oxide (nGO), nano-hydroxyapatite(nHA) and nano-cellulose (nC), with various concentrations. The objective of the study was to explorethe effects of porogen concentration and foaming process parameters on the morphology and me-chanical properties of three-dimensional porous structures that can be used as temporary scaffolds intissue engineering. The structures were manufactured using scCO2as a blowing agent, at two variousfoaming pressures (9 MPa and 18 MPa), at three different temperatures (323 K, 343 K and 373 K) fordifferent saturation times (0.5 h, 1 h and 4 h). In order to examine the utility of porogenes, a number oftests, such as static compression tests, thermal analysis and scanning electron microscopy, have beenperformed. Analysis of experimental results showed that the investigated materials demonstrated highmechanical strength and a wide range of pore sizes. The obtained results suggest that PCL porousstructures are useful as biodegradable and biocompatible scaffolds for tissue engineering.
EN
The environmental degradation of poly(ε-caprolactone)[PCL] in natural fresh water (pond) and in The Baltic Sea is presented in this paper. The characteristic parameters of both environments were measured during experiment and their influence on the biodegradation of the samples was discussed. The loss of weight and changes of surface morphology of polymer samples were tested during the period of incubation. The poly(ε-caprolactone) was more biodegradable in natural sea water than in pond. PCL samples were completely assimilated over the period of six weeks incubation in The Baltic Sea water, but after forty two weeks incubation in natural fresh water the polymer weight loss was about 39%. The results have confirmed that the investigated polymers are susceptible to an enzymatic attack of microorganisms, but their activity depends on environments.
EN
The results of experimental investigations into foaming process of poly(ε-caprolactone) using supercritical CO2 are presented. The objective of the study was to explore the aspects of fabrication of biodegradable and biocompatible scaffolds that can be applied as a temporary three-dimensional extracellular matrix analog for cells to grow into a new tissue. The influence of foaming process parameters, which have been proven previously to affect significantly scaffold bioactivity, such as pressure (8-18 MPa), temperature (323-373 K) and time of saturation (1-6 h) on microstructure and mechanical properties of produced polymer porous structures is presented. The morphology and mechanical properties of considered materials were analyzed using a scanning electron microscope (SEM), x-ray microtomography (μ-CT) and a static compression test. A precise control over porosity and morphology of obtained polymer porous structures by adjusting the foaming process parameters has been proved. The obtained poly(ε-caprolactone) solid foams prepared using scCO2 have demonstrated sufficient mechanical strength to be applied as scaffolds in tissue engineering.
PL
Folie zawierające polilaktyd jako osnowę polimerową, montmorylonit jako napełniacz oraz poli(ε-kaprolakton) jako kompatybilizator naświetlano promieniowaniem UV-C (max 254nm) w odstępach dwu godzinnych do 16 godzin. Wpływ napełniacza oraz obecności kompatybilizatora na proces fotodegradacji analizowano przeprowadzając badania właściwości termicznych, zarówno wyjściowych materiałów jak i po różnych czasach ekspozycji na UV. Pod uwagę brano między innymi następujące parametry: stabilność termiczną, temperaturę zeszklenia czy stopień krystaliczności. Otrzymane wartości wskazują, iż wprowadzenie poli(ε-kaprolaktonu) jak i montmorylonitu powoduje wzrost stopnia krystaliczności materiałów, co jest jednym z kluczowych czynników wpływających na proces fotodegradacji. Na podstawie uzyskanych wyników stwierdzono, iż obecność napełniacza podobnie jak i kompatybilizatora poprawia odporność kompozytów polilaktydowych na działanie promieniowania UV.
EN
Films consisting of polylactide as polymer matrix, montmorillonite as filler and poly(ε-caprolactone) as compatibilizing agent were irradiated with UV (254 nm) at intervals of 2-16 hours. Effect the presence of filler and compatibilizing agent has got on photodegradation process was analyzed by examination of thermal properties of both the starting material and the material after various times of exposure to UV radiation. The following parameters were taken into account: thermal stability, temperature of glass transition as well as degree of crystallinity. Determined values indicate that the introduction of a compatibilizing agent and a nanofiller into polymer matrix increases degree of crystallinity of obtained materials. Degree of crystallinity is an important factor influencing photodegradation process. Based on obtained results it has been established that the presence of a nanofiller as well as a compatibilizing agent improves thermal stability of polylactide composites exposed to UV radiation.
PL
Określono wpływ parametrów realizacji procesu spieniania poli(ε-kaprolaktonu) przy użyciu CO2 w stanie nadkrytycznym na właściwości otrzymywanych struktur porowatych. Zbadano wpływ na przebieg procesu następujących parametrów: temperatura (50-M00°C), ciśnienie (8÷18 MPa), czas nasycania polimeru ditlenkiem węgla (1÷6 h), szybkość dekompresji mieszaniny (1600-3600 bar/min) oraz czas spieniania (5÷30 min). Wytworzone struktury poddano analizie przy użyciu specjalistycznych metod badań. Wykazano silny wpływ warunków realizacji procesu spieniania na strukturę i właściwości pian stałych.
EN
The influence of process conditions of supercritical foaming of poly(ε-caprolactone) (PCL) on properties of obtained porous foams was investigated. The foaming experiments were performed at temperature varied in a range from 25 to 100°C, pressure from 8 to 18 MPa, saturation time from 1 to 6 hours with different depressurization rates. Finally, the properties of obtained porous three-dimensional structure using various analytical methods were identified. A strong influence of process parameters on morphology and mechanical properties of solid foams were noticed.
6
Content available remote Experimental investigations into foaming of biodegradable polymers using scCO2
EN
Results of experimental investigations of batch foaming of poly(ε-caprolactone) using scCO2 are presented in the paper. The high pressure system consisting of CO2 cylinder, scCO2 pump, high pressure cell, pressure and temperature gauge and back pressure regulator was applied in the experiments. The porous three-dimensional solid-gas structures were prepared for the following range of process parameters: temperature 298+373 K, pressure 8+18 MPa, time 1+4 h and depressurization rate 0.007+4 MPa/s. The significant influence of process parameters on the obtained foams morphology was identified.
PL
W pracy przedstawiono wyniki badań doświadczalnych procesu spieniania polikaprolaktonu (PCL) przy użyciu CO2 w stanie nadkrytycznym. Badania przeprowadzono w instalacji złożonej z butli CO2, pompy do płynów nadkrytycznych, komory wysokociśnieniowej, miernika ciśnienia i temperatury oraz regulatora ciśnienia wstecznego. Badania wykonano dla zakresu zmienności parametrów operacyjnych: temperatura: 398÷373 K, ciśnienie: 8÷18 MPa, czas nasycania: 1÷4 h, szybkość dekompresji: 0,007÷4 MPa/s. Wykazano silny wpływ warunków realizacji procesu spieniania na strukturę wytwarzanych pian.
EN
In the present work a three dimensional composite scaffolds for bone tissue engineering were created by a carding and needle-punch processes. Highly porous nonwoven fabrics were obtained from PCL and PCL/n-HAp cut fibers without the use of any chemicals during the manufacturing process. The properties of nonwoven scaffolds were examined by SEM, FTIR, DSC and TGA methods. The average pore diameter as well as the pore size distribution of nonwoven fabrics were measured by a capillary flow porometry. The obtained results suggest that needle-punching method can be used to produce highly porous microstructures with an interconnected pore network.
PL
Otrzymano szereg próbek biomedycznego poli(ε-kaprolakton)u (PCL) stosując metodę polimeryzacji z otwarciem pierścienia katalizowanej 2-etyloheksanianem cyny (II). Uzyskane produkty polireakcji poddano operacji oczyszczania z pozostałości po katalizatorze cynoorganicznym. Zawartość metalu w otrzymanych polimerach oznaczano za pomocą elektrotermicznej absorpcyjnej spektrometrii atomowej. Toksyczność uzyskanych polimerów oceniano w odniesieniu do bakterii luminescencyjnych oraz dwóch pierwotniaków. Wstępne wyniki zaprezentowane w niniejszym artykule sugerują, że zastosowane operacje oczyszczania redukują zawartość cyny w polimerach bez ich degradacji. Można również stwierdzić, że polimery o zredukowanej zawartości cyny nie wykazują toksyczności w stosunku do bakterii luminescencyjnych V. fischeri oraz pierwotniaków S. ambiguum i T. termophila.
EN
A series of biomedical poly(ε-caprolactone)s were synthesized by the ring-opening polymerization of ε-caprolactone in the presence of tin(II) 2-ethylhexanoate. The obtained products were subjected to the purification procedures for removing the residual of tin catalyst. The metal content in the received polymers were determined using the Electrothermal Atomic Absorption Spectrometry. The toxicity of the resulted polymers was evaluated using bacterial luminescence test and two protozoan assays. The preliminary studies presented in this paper suggest that the purification of the polymers reduces tin concentration in the final products without causing product degradation. It was found that the purified polymers are not toxic relative to luminescent bacteria V. fischeri and two ciliated protozoans S. ambiguum and T. termophila.
EN
The paper presents study performed to investigate the possible use of modified poly(ε-caprolactone) as a potential material for catheters. Experiment verifies if thermal modification using liquid nitrogen (LN) changes microstructure, biostability, mechanical and physicochemical properties of polymer. The easiness of forming material into tubes to confirm handiness was checked.
EN
The main limitation of embryos transfer is the lack of catheters for their obtaining and transferring which would have desirable and confirmed biological properties ensuring high bioconcordance and low toxicity. Catheters used routinely for embryos obtaining and transfer are tools used for insemination, urology and other medical purposes, but their bioconcordance with embryos was never confirmed. For these reasons in our studies we attempted to develop the modern set of catheters designed for the contact with embryos, based on the biomaterial characterized by good biological and mechanical properties such as with optimal resilience and elastic properties, and capable to be free shaped in the form of a tube of 1-2 mm diameter. The material which hypothetically fulfills biological requirements and at the same time gives possibility of free shaping is resorbable polymer used for the long time in many fields of medicine is poly-ε-caprolactone (PCL). Because of its biological and physical properties it was taken into consideration to use this biomaterial for in vitro embryos culture and for cryoconservation. The aim of the study was verification of biological properties of poly-ε-caprolactone (PCL) as the material dedicated to biotechnology of animal reproduction and gynecology and evaluation of possibility of poly-ε-caprolactone (PCL) application as a potential material for production of medical devices, as catheters for obtaining and transporting of embryos as well as dishes for embryos culture in vitro and covers for cryoconservation. The possible application of this biomaterial needs verification of its biological properties on embryos culture. The foil discs made of the polycaprolactone, thickness 0.5 mm, diameter 3.5 mm, were prepared in two forms: the reference one (nPCL) and thermally modified by freezing in liquid nitrogen (mPCL). The verification of PCL bioconcordance was performed by evaluation of 102 pig embryos at the development stage of 2 to 4 blastomers. To evaluate poly-ε-caprolactone bioconcordance 5-day long culture of the embryos was performed on the evaluating material, not frozen (nPCL) and frozen in liquid nitrogen (mPCL) and additionally culture after short contact with poly-ε-caprolactone lasting 15 minutes (nPCL-15). In all evaluated study groups the development of embryos was suppressed shortly after transfer to the culture with PCL. In the control group 74-78% of the embryos reached blastocyst stage. Because of cytotoxic influence of polycaprolacton on embryos it cannot be used as the material for catheter production used in biotechnology of animal reproduction and other materials used for in vitro culture and cryoconservation.
PL
Poli(ε-kaprolakton) jest materiałem wykorzystywanym jako rusztowanie dla komórek w inżynierii tkankowej kości. Na podstawie danych z literatury oraz naszych własnych badań nad reakcją komórek osteogennych na bezpośredni kontakt z poli(ε-kaprolaktonem) można przypuszczać, iż materiał ten może wpływać na poziom markerów różnicowania komórek w kierunku osteoblastów. Celem niniejszej pracy było zbadanie wpływu poli(ε-kaprolaktonu) na ekspresję oraz aktywność wczesnego markera procesu różnicowania komórek osteogennych, jakim jest fosfataza zasadowa. Przy użyciu reakcji łańcuchowej polimerazy DNA z analizą ilości produktu w czasie rzeczywistym (real-time PCR) analizowano ekspresję genu fosfatazy zasadowej natomiast aktywność enzymu oznaczono kolorymetrycznym testem firmy Sigma. Otrzymane wyniki wskazują, iż kontakt ludzkich osteoblastów z powierzchnią poli(ε-kaprolaktonu) powoduje podwyższoną ekspresję genu fosfatazy zasadowej oraz podwyższoną aktywność tego enzymu. Fosfataza zasadowa nie jest specyficznym markerem osteoblastów, jednakże jej podwyższony poziom towarzyszy wczesnym etapom różnicowania w kierunku fenotypu komórek osteogennych. Uzyskane wyniki uzasadniają podjęcie dalszych badań nad możliwym wpływem poli(ε-kaprolaktonu) na różnicowanie osteoblastów.
EN
Poly(ε-caprolactone) is a material used as a scaffold for cells in bone tissue engineering. On the basis of data from literature as well as own research it was concluded that this material can influence the levels of markers of cell differentiation towards osteoblasts. The aim of this paper was to investigate the effect of poly(ε-caprolactone) on the expression and the activity of the early marker of the cell osteogenic differentiation process – alkaline phosphatase (ALP). Using the quantitative real time polymerase chain reaction (real-time PCR) gene expression of the alkaline phosphatase was analyzed; however, the activity of the enzyme was determined with colorimetric assay from the Sigma company. The obtained results indicated that the contact of human osteoblasts with the surface of poly(ε-caprolactone) causes an increased gene expression of alkaline phosphatase and an increased activity of this enzyme. Although a high level of ALP does not prove the PCL influence on the osteogenic differentiation of cells into mature osteoblasts, because this enzyme is a non-specific marker of the differentiation process. The obtained results justify undertaking further studies on the possible impact of poly(ε-caprolactone) on osteoblast differentiation.
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