Polyurethane (PUR) and polyurethane/poly(d, l-lactide) acid (PUR/PDLLA) based scaffolds coated with Bioglass® particles for application in bone tissue engineering were fabricated. The slurry-dipping method was used for coating preparation. The homogeneous structure of the Bioglass® coatings on the surface of the PUR and PUR/PDLLA foams indicated a good adhesion of the bioactive glass particles to polyurethane without any additional surface treatment. In vitro studies in simulated body fluid (SBF) were performed to study the influence of Bioglass® coating on biodegrability and bioactivity of PUR-based scaffolds. The surface of Bioglass®-coated samples was covered by a layer of carbonate-containing apatite after 7 days of immersion in SBF, while in uncoated polymer samples apatite crystals were not detected even after 21 days of immersion in SBF. The apatite layer was characterized by scanning electron microscopy (SEM), EDS analysis and attenuated total reflectance–Fourier transform infrared spectrometry (FTIR–ATR). Weight loss measurements showed that the in vitro degradation rate of the composite scaffolds in SBF was higher in comparison to uncoated polyurethane samples. PUR and PUR/PDLLA foams with Bioglass® coating have potential to be used as bioactive, biodegradable scaffolds in bone tissue engineering.
Event Abstract Back to Event The effect of drug loading technics on in vitro release profile from multifunctional chitosan/polyurethane composites. Aleksandra J. Kucharska1 and Monika Bil1 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Poland Introduction: The concept of multifunctional devices that combine drug eluting components together with functional prosthetic implants, represents an emerging clinical technology that promises to provide functional enhancement to implant devices in various clinical applications[1],[2]. The properly designed drug delivery system can allow for a precise drug release control, which refers to the amount of released dose, the drug release profile and the speed of release[3]. In general, the choice of the proper drug loading technic can be decisive for obtaining the suitable and desired drug release from biomaterial[4]. The aim of this work was to compare different methods of the drug loading into chitosan/ polyurethane matrix in terms of optimization of the developed systems. Materials and Methods: In the first stage chitosan microspheres were prepared using emulsification/cross-linking method[5]. Chitosan solution in acidic acid containing gentamicin (3 or 6 wt. % vs. chitosan mass) was emulsified in the dispersion medium consisting of liquid paraffin stabilized by the sorbitan monooleate. Triphosphate pentasodium (TPP) and glutaraldehyde (25 or 50 wt.% solution in H2O) were used as a cross-linking agents. Next the microspheres loaded with gentamicin were added to the synthesis of polyurethane matrix (PU). PU networks based on three-branched hydroxyl terminated caprolactone (CL) and glycolide-co-lactide (PLGA) oligomers were synthesized using 1,6-hexamethylene diisocyanate (HMDI) and dibutyltin dilaurate as the catalyst. Additionally, polyurethanes consisting of chitosan macromolecule segment were synthesized and drugs were incorporated directly into the polymer matrix during synthesis. In vitro release study was performed after immersion of the composites in PBS according to the method used by Zang[6]. Results and Discussion: Two types of biodegradable polyurethane composites containing chitosan microspheres or chitosan macromolecule segments were obtained. Chitosan microspheres with mean diameter of 8 μm (Fig.1) were distributed within polymer matrix. Drug loading efficiency in case of microspheres system increased significantly form 3% for microspheres crosslinked with 50 wt.% glutaraldehyde to 60% for microspheres crosslinked with 25 wt%. glutaraldehyde. Drug release profile from the gentamicin containing-microspheres composites proved to be stable and sustained for more than a month (Fig. 2.). In case of the polyurethane composites containing the microspheres with the drug loaded directly to the polymer matrix, the higher burst release was observed due to the facilitated diffusion of the drug. Conclusion: The results of drug release study showed that the drug release kinetics from the chitosan/polyurethane composites system can be modified by drug loading method and the cross-linking degree of chitosan microspheres. The study confirms that these systems could be successfully used un regenerative medicine as drug carriers. This work was financed by National Science Centre on the basis of a decision number DEC- 2012/07/D/ST8/02588.References:[1] MEH El-Sayed, A. S. Hoffman, P.S. Stayton, Smart polymeric carriers for enhanced intracellular delivery of therapeutic macromolecules, Expert Opinion on Biological Therapy 5(1) (2005) 23-32.[2] M.R.Aguilar, C. Elvira, A. Gallardo, B. Vázquez, and J.S. Román. Smart polymers and Their applications as biomaterials.[3] A.K. Bajpai ∗, S. K. Shukla, S. Bhanu, S. Kankane. Responsive polymers in controlled drug delivery. Progress in Polymer Science 2008;11(33): 1088–1118[4] C. Wischke, A. T. Neffe, S. Steuer, A. Lendlein. Comparing techniques for drug loading of shape-memory polymer networks--effect on their functionalities. Eur J Pharm Sci. 2010 Sep 11;41(1):136-47.[5] E. Szymańska, K. Winnicka, M. Muśko. Otrzymywanie mikrosfer chitozanowych metodą emulsyjno-sieciującą z zastosowaniem trifosforanu (TPP) I aldehydu glutarowego (GLT).[6] Zhang X, Wyss UP, Pichora D, Goosen MFA. Biodegradable controlled antibiotic release devices for osteomyelitis: optimization of release properties. J Pharm Pharmacol 1994;46:718–24. Keywords: Drug delivery, material design, Smart material, Nano/micro particle Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials for therapeutic delivery Citation: Kucharska AJ and Bil M (2016). The effect of drug loading technics on in vitro release profile from multifunctional chitosan/polyurethane composites.. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00674 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Aleksandra J Kucharska Monika Bil Google Aleksandra J Kucharska Monika Bil Google Scholar Aleksandra J Kucharska Monika Bil PubMed Aleksandra J Kucharska Monika Bil Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.
The textile market is a vast industry that utilizes antimicrobial polymeric materials, including various types of fabrics, for medical and personal protection applications. Therefore, this study focused on examining four types of antimicrobial fillers, namely, metal oxides (zinc, titanium, copper) and nanosilver, as fillers in Polyamide 12 fibers. These fillers can be applied in the knitting or weaving processes to obtain woven polymeric fabrics for medical applications. The production of the fibers in this study involved a two-step approach: twin-screw extrusion and melt spinning. The resulting fibers were then characterized for their thermal properties (TGA, DSC), mechanical performance (tensile test, DMA), and antifungal activity. The findings of the study indicated that all of the fibers modified with fillers kill Candida albicans. However, the fibers containing a combination of metal oxides and silver showed significantly higher antifungal activity (reduction rate % R = 86) compared to the fibers with only a mixture of metal oxides (% R = 21). Furthermore, the inclusion of metal oxides and nanosilver in the Polyamide 12 matrix hindered the formation of the crystal phase and decreased slightly the thermal stability and mechanical properties, especially for the composites with nanosilver. It was attributed to their worse dispersion and the presence of agglomerates.
Fibrous shape memory scaffolds composed of thermoplastic polyurethane based on a mixture of polycaprolactone diols were fabricated. The effect of the fiber diameter and arrangement– random (rPU) or aligned (aPU), on crystallinity, mechanical properties, and shape memory was analyzed. The diameters of the fibers were controlled by changing the concentration of polyurethane (PU) solutions in the range of 5% to 16% and fibers alignment by utilization of different collectors. The chemical structure was confirmed by Fourier Transformed Infrared spectroscopy (FTIR), crystallinity was evaluated based on differential scanning calorimetry (DSC,) and mechanical properties were measured by the tensile test. Additionally, shape memory programming was performed using a dynamic mechanical analyzer (DMA), and shape recovery was evaluated in the air and in the water environment. DSC results showed that the electrospinning process did not change the crystallinity or melting temperature of synthesized thermoplastic polyurethanes. The melting temperature of the crystalline switching segments was around 26–27 °C, and the crystalline phase of hard segments was around 130 °C. Shape memory properties were analyzed in the contest of the fiber diameter and alignment of the fibers, while changes in the fibers’ diameters from 360 nm to 1760 nm did not result in significant changes in shape recovery coefficient (Rr) especially evaluated in the air. The longitudinal fiber alignment enhanced mechanical and shape recovery to up to 96% for aPU, with the highest fiber diameter when evaluated in water.
Event Abstract Back to Event Core-shell polyurethane nanofibers with shape memory for drug release applications Ewa Kijeńska1, Monika Bil1, Mariusz Uchman2 and Wojciech Swieszkowski1 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Poland 2 Charles University in Prague, Faculty of Science, Czechia Introduction: Coaxially electrospun polymeric nanofibers are promising carriers for versatile bio-active agents, growth factors and drugs, allowing for their control release. On the other hand shape memory polyurethanes have excellent thermal shape memory effect and demonstrate high biocompatibility. Thus recently core-shell nanofibers based on this kind of polymers have gained much attention in various biomedical applications like cardiovascular stents. In this study preliminary investigation of electrospun fibers made of polyurethane and polyurethane/gelatine with encapsulated microspheres towards drug release and shape memory was performed. Materials and Methods: Polyurethane PCL/PLLA with shape memory based on PCL and PLLA was synthesized by polymerization in our laboratory. PCL-PEO nanoparticles ere prepared according to the protocol: 10mg of each copolymer was added to 90% THF/water mixtures and left shaken overnight till full dissolution copolymers was achieved. Then solutions were added drop-by-drop to water under vigorous stirring. Finally the solutions were dialyzed against water. In our experiments, for comparison, core –shell fibers with PCL/PLLA; PCL/PLLA:Gelatin [90:10], PCL/PLLA:Gelatin [80:20] in HFP as a shell and microspheres in water as a core, were prepared using the co-axial electrospinning. Results and Discussion: Electrospun uniform and bead free fibrous structures were successfully fabricated using co-axial electrospinning. SEM micrographs (Fig.1) of electrospun mesh revealed porous, beadless, fibrous topography. TEM investigation confirmed core-shell character of obtained fibers. Contact angle measurements data supported the fact that the incorporation of gelatin made meshes more hydrophillic compared fibers with pure polyurethane shell, thus more sufficient for biomedical applications. Release studies showed potential of use of this types of fibers for encapsulation of the drug loaded microspheres. Conclusions: Our studies suggest the potential application of co-axially electrospun PCL/PLLA polyurethane fibrous carriers with encapsulated drug loaded microspheres as a suitable substrate for target tissue engineering and indicate co-axial electrospinning technique as a promising method for fabrication of polyurethane fibers with improved functionality. The authors would like to thank the National Centre for Research and Development (Grant no: LIDER/037/673/L-4/12/NCBR/2013) for providing financial support to this project. Keywords: nanofiber, Polymeric material, medical application, Biofunction Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Electrospinning and related technologies Citation: Kijeńska E, Bil M, Uchman M and Swieszkowski W (2016). Core-shell polyurethane nanofibers with shape memory for drug release applications. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02867 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Google Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Google Scholar Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski PubMed Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.
Preparation of scaffolds for tissue regeneration requires elucidation of chemical and physical processes induced by ionizing radiation during radiation sterilization of polymeric materials used for these purposes. Such treatment induces many unintended and desired reactions that lead either to degradation or cross-linking of macromolecules. It was found that in poly(ester urethane) the ester segments are responsible predominantly for radiation induced phenomena. Some radicals generated following irradiation were identified under cryogenic conditions. Upon exposure to sterilizing dose cross-linking was confirmed on the basis of rheological changes in melted polymers. The results obtained by EPR spectroscopy and DRS revealed a relatively high susceptibility of poly(ester urethanes) on oxidation.
Graphene and its derivatives have attracted scientists’ interest due to their exceptional properties, making them alluring candidates for multiple applications. However, still little is known about the properties of as-obtained graphene derivatives during long-term storage. The aim of this study was to check whether or not 14 months of storage time impacts graphene oxide flakes’ suspension purity. Complementary micro and nanoscale characterization techniques (SEM, AFM, EDS, FTIR, Raman spectroscopy, and elemental combustion analysis) were implemented for a detailed description of the topography and chemical properties of graphene oxide flakes. The final step was pH evaluation of as-obtained and aged samples. Our findings show that purified flakes sustained their purity over 14 months of storage.
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