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This study explores utilization of biodegradable and biocompatible polymers for controlled release of natural bioactive substance. For that purpose, poly(ε-caprolactone) (PCL) beads, cellulose acetate (CA) film, and poly lactic- co-glycolic acid (PLGA) flakes were impregnated with thymol by employing environmentally friendly process of supercritical carbon dioxide (scCO2) impregnation. At selected pressure and temperature, prolongation of operating time increased thymol loading. Pure scCO2 did not affect CA film with average pore diameter of approximately 3 µm, while it enabled change of PCL beads and PLGA flakes into foams with average pore diameter approximately 175 µm and 87 µm, respectively. Additionally to scCO2, thymol acted as a plasticizer increasing pore size of polymers up to three times. Kinetic of thymol release from selected samples was tested using phosphate buffer saline at 37°C and successfully described with Korsmeyer–Peppas, zero-order, first-order, and Higuchi models. The suggested method of PCL, CA, and PLGA supercritical impregnation led to development of porous, solvent free, added-value materials that release thymol in a controlled manner from 5 h to several days.

Implantation of biomaterials and hybrid constructs in tissue engineering approaches presents major limitations such as inflammatory reaction and the lack of vasculature integration. Therefore, new strategies are needed to enhance implant function, immune protection, and revascularization. In this work, we developed fibrous meshes composed of fucoidan (Fu), a sulfated polysaccharide extracted from brown algae, and polycaprolactone (PCL), a synthetic biodegradable polymer, using the airbrush technique. The chemical characterization by FTIR, EDS, and XPS confirmed the presence of the two polymers in the structure of airbrushed nanofibrous meshes (ANFM). Moreover, these nanofibrous exhibited good wettability and mechanical properties envisaging their application as templates for biomaterials and cell culture. The developed ANFM were directly cultured with human pulmonary microvascular endothelial (HPMEC-ST1.6R) cells for up to 7 days. Biological results demonstrated that ANFM comprising Fu promoted cellular attachment, spreading, and proliferation of human endothelial cells. The angiogenic potential of ANFM was further evaluated by onplantation of PCL and PCL/Fu ANFM in chick chorioallantoic membrane (CAM). In ovo and ex ovo results showed that the incorporation of Fu increased the proangiogenic potential of ANFM. Altogether, the results suggest that airbrush biocomposite meshes could be used as a biomaterial substrate to promote vascularization., Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through Structured projects NORTE-01-0145-FEDER-000021 and NORTE-01-0145-FEDER-000023. Financial support from the Portuguese Foundation for Science and Technology (FCT) is also acknowledged through PhD fellowship SFRH/BD/112139/2015 and R&D&I projects PTDC/CTM-CTM/29813/2017 and PTDC/BII-BIO/31570/2017.

International audience; Additive manufacturing is changing tissue engineering by offering pathways to otherwise unattainable, highly complex scaffold morphologies. Linear poly(propylene fumarate) (PPF) oligomers have demonstrated remarkable properties for 3D printing of porous gyroid scaffolds using continuous digital light processing (cDLP). Nevertheless, the narrow molar mass ((M-n) over bar) range with suitable viscosity properties for printing severely limits the printing speed, the breadth of mechanical properties, and the resorption window of the scaffolds. To overcome this constraint, we report the divergent synthesis of four-arm PPF using the sugar-based alcohol meso-erythritol as an initiator. Using a combination of H-1 NMR spectroscopy, size exclusion chromatography (SEC), MALDI-ToF spectrometry and viscosity measurements, the well-defined star-shape architecture was confirmed. Subsequently, printable resins based on star PPF were prepared and showed complex viscosity decreasing as the total (M-n) over bar increases, allowing rapid printing of PPF with (M-n) over bar nearly eight times larger than the largest linear PPF oligomer printed previously.

International audience; Micelles of poly(epsilon-caprolactone)-b-poly(N,N-diethylaminoethyl methacrylate)/(N-(3-sulfopropyl-N-methacryloxyethy-N,N-diethylammonium betaine)) (PCL-PDEAPS) and poly(epsilon-caprolactone)-b-poly(ethylene glycol) (PCL-PEG) were prepared and characterized. The interactions of micelles with model proteins such as bovine serum albumin (BSA), lysozyme (Ly), fibrinogen (Fg) and plasma were studied from adsorption quantity, micelle size, polydispersity index (PDI) and zeta-potential measurements. The adsorption quantity of negatively charged proteins on PCL-PDEAPS micelles containing zwitterionic sulfobetaine is larger than on non-ionic PEG-PCL micelles. The adsorption amount increases with the increase of zwitterionic content. And the quantity of adsorbed Fg is much higher than that of BSA because the former is much larger than the latter. In contrast, adsorption of positively charged Ly on copolymer micelle is very low. The interactions between micelles and model proteins are not only dependent on the hydration of zwitterions in PCL-PDEAPS micelles, but also on the electrostatic effect between proteins and micelles. Moreover, the adsorption of three model proteins on the mixed micelles of PCL-PDEAPS and PCL-PEG copolymers is related to the ratio of two copolymers. Denaturation of the proteins is not detected during adsorption and detachment process. PCL-PDEAPS micelles with positive charge are not swallowed by the macrophages after plasma absorption, in contrast to PCL-PEG micelles. (C) 2018 Elsevier B.V. All rights reserved.

Poly(e-caprolactone) (PCL) films reinforced with polylactide (PLA) microfibers were prepared by two methodologies: a) melt pressing of an electrospun PLA mat between two PCL films, and b) melt pressing of a co-electrospun mat composed of PLA microfibers and PCL nanofibers. Electrospinning conditions were selected for each polymer to obtain films loaded with 10, 20 and 30 wt% of PLA. Thermal and mechanical properties varied depending on the preparation method. Thus, PLA crystallinity was higher when films were obtained by the co-electrospinning process, as revealed from DSC and synchrotron X-ray diffraction data since cold crystallization of the highly oriented PLA microfibers was favored in the subsequent heating run when they were in close contact with PCL nanofibers. Samples obtained by co-electrospinning also showed higher mechanical properties (e.g. Young modulus) with increasing PLA load. In this case, fracture surfaces showed significant interactions between fibers and the PCL matrix and decreased fiber pull-out. All fabrics were also loaded with chlorhexidine (CHX) as a hydrophilic bactericide agent. A delayed release was observed when the drug was only loaded into the electrospun PLA microfibers, and diffusion varied with the method of preparation. In all cases, samples had a clear bactericide effect against Gram positive and Gram negative bacteria. Nevertheless, the protective effect was slightly lower when CHX was only loaded in the reinforcing PLA microfibers.

Background Biodegradable PCL- b-PTMC- b-PCL triblock copolymers based on trimethylene carbonate (TMC) and ε-caprolactone (CL) were prepared and used in the 3D printing of tissue engineering scaffolds. Triblock copolymers of various molecular weights containing equal amounts of TMC and CL were prepared. These block copolymers combine the low glass transition temperature of amorphous PTMC (approximately -20°C) and the semi-crystallinity of PCL (glass transition approximately -60°C and melting temperature approximately 60°C). Methods PCL- b-PTMC- b-PCL triblock copolymers were synthesized by sequential ring opening polymerization (ROP) of TMC and ε-CL. From these materials, films were prepared by solvent casting and porous structures were prepared by extrusion-based 3D printing. Results Films prepared from a polymer with a relatively high molecular weight of 62 kg/mol had a melting temperature of 58°C and showed tough and resilient behavior, with values of the elastic modulus, tensile strength and elongation at break of approximately 120 MPa, 16 MPa and 620%, respectively. Porous structures were prepared by 3D printing. Ethylene carbonate was used as a crystalizable and water-extractable solvent to prepare structures with microporous strands. Solutions, containing 25 wt% of the triblock copolymer, were extruded at 50°C then cooled at different temperatures. Slow cooling at room temperature resulted in pores with widths of 18 ± 6 μm and lengths of 221 ± 77 μm, rapid cooling with dry ice resulted in pores with widths of 13 ± 3 μm and lengths of 58 ± 12 μm. These PCL- b-PTMC- b-PCL triblock copolymers processed into porous structures at relatively low temperatures may find wide application as designed degradable tissue engineering scaffolds. Conclusions In this preliminary study we prepared biodegradable triblock copolymers based on 1,3-trimethylene carbonate and ε-caprolactone and assessed their physical characteristics. Furthermore, we evaluated their potential as melt-processable thermoplastic elastomeric biomaterials in 3D printing of tissue engineering scaffolds.

The objective of this work was to characterize the toxicological profile of a newly developed sunscreen formulation based on polymeric nanocapsules (NCs) loading benzophenone-3 (BZP3). NCs composed of poly(ε-caprolactone) carrot oil and Pluronic® F68 were produced by emulsification-diffusion method. Their mean particle size (Z-Ave) ranged from 280 to 420 nm, polydispersity index (PDI) was below 0.37, while zeta potential (ZP) reached about |+11 mV|. No cytotoxic effects were observed in L929 fibroblast cell line for the blank (i.e., non-loaded) NCs and BZP3-loaded NCs (BZP3-NCs). The semi-solid sunscreen formulation was stable over time (centrifugation testing) and exhibited non-Newtonian pseudoplastic behavior, which is typical of products for topical application onto the skin. The sun protection factor (SPF) value reached 8.84, when incorporating BZP3-NCs (SPF of 8.64) into the semi-solid formulation. A synergistic effect was also observed when combining the formulation ingredients of nanocapsules, i.e., SPF of carrot oil was 6.82, blank NCs was 6.84, and BZP3-loaded NCs was 8.64. From the hen’s egg-chorioallantoic membrane test (HET-CAM) test, the non-irritation profile of the developed formulations could also be confirmed. The obtained results show a promising use of poly(ε-caprolactone) nanocapsules to be loaded with lipophilic sunscreens as benzophenone-3., This research was funded by Coordenação Aperfeiçoamento de Pessoal de Nivel Superior (CAPES), Fundação de Amparo à Pesquisa do Estado de Sergipe (FAPITEC), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). This work was also financed through the project M-ERA-NET/0004/2015 and scholarship grant SFRH/BD/130555/2017, from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) from national funds, and co-financed by FEDER, under the Partnership Agreement PT2020., info:eu-repo/semantics/publishedVersion

In this work, novel composites based on poly(&epsilon, caprolactone) (PCL) were prepared and characterized in terms of morphological, thermal, rheological and mechanical properties. Hollow glass microspheres (HGM), alone or surface modified by treatment with (3-aminopropyl)triethoxysilane (APTES) in order to enhance the compatibility between the inorganic particles and the polymer matrix, were used to obtain lightweight composites with improved properties. The silanization treatment implies a good dispersion of filler particles in the matrix and an enhanced filler&ndash, polymer adhesion. The addition of HGM to PCL has relevant implications on the rheological and mechanical properties enhancing the stiffness of the material. Furthermore, the presence of HGM strongly interferes with the crystallization behavior and thermo-oxidative degradation of PCL. The increase of PCL crystallization rate was observed as a function of the HGM amount in the composites. Finally, rotational molding tests demonstrated the possibility of successfully producing manufactured goods in PCL and PCL-based composites on both a laboratory and industrial scale.

In this study, novel active films made of poly(ε-caprolactone) (PCL) containing a solid dispersion of sage extract (SE) were developed by means of the electrospinning technique and subsequent annealing treatment. Initially, the antioxidant and antimicrobial potential of SE was confirmed. Thereafter, the effect of SE incorporation at different loading contents (5%, 10%, and 20%) on the physicochemical and functional properties of the films was evaluated. The films were characterized in terms of morphology, transparency, water contact angle, thermal stability, tensile properties, water vapor, and aroma barrier performances, as well as antioxidant and antimicrobial activities. Thin, hydrophobic films with good contact transparency were produced by annealing of the ultrathin electrospun fibers. Interestingly, the effect of SE addition on tensile properties and thermal stability of the films was negligible. In general, the water vapor and aroma permeability of the PCL-based films increased by adding SE to the polymer. Nevertheless, a strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability, and a strong activity against foodborne pathogens Staphylococcus aureus and Escherichia coli were achieved by SE incorporation into PCL matrix. Overall, the obtained results suggest great potential of the here-developed PCL-based films containing SE in active food packaging applications with the role of preventing oxidation processes and microbial growth, This research was funded by COST Action FP1405 (STSM reference number 39168), the EU H2020 ResUrbis project (Reference number 730349) and the Ministry of Education, Science and Technological Development (Republic of Serbia) project number III46010., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Poly(epsilon-caprolactone) (PCL) nanocomposites with hybrid clay-supported carbon nanotubes (Clay-CNT) in concentrations 0.5, 1.0 and 2.5 wt% were prepared by melt mixing. Mechanical, structural and thermal properties of the nanocomposites were studied. All nanocomposites exhibited similar stress-strain patterns to those of neat PCL but, with increasing nanofiller content yield point and Young's Modulus values increased, despite the absence of chemical interactions between PCL and Clay-CNT. It was also found that the crystallinity of the nanocomposites is the same as for neat PCL, but the nanofiller acts as nucleating agent which promotes the crystallization and also allows it to occur at higher temperatures. Thermal stability is instead negatively influenced by the nanofiller, since Clay-CNT catalyzes the decomposition of PCL at lower temperature. The monomer epsilon-caprolactone is the main decomposition product resulting from intramolecular esterification while cis-elimination at ester bonds (beta-hydrogen bond scission) is favored at higher temperatures. (C) 2016 Elsevier B.V. All rights reserved.

[EN] The present work is focused on the development of binary blends from poly(hydroxybutyrate) (PHB) and poly(caprolactone) (PCL). Miscibility, mechanical and thermal properties as well as blends morphology are evaluated in terms of the blend composition. Binary PHB PCL blends were manufactured by melt compounding in a twin screw co-rotating extruder and injection molded. The composition of PHB PCL covered the full range between individual polymers at 25 wt% increments. The obtained results show that PCL acts as an impact modifier, thus leading to an increase in flexibility and ductility as the PCL content in the PHB PCL blends increases with a noticeable increase in elongation at break and on the energy absorption in impact conditions. The tensile strength and the elastic modulus decrease with increasing PCL content in the PHB PCL blends; nevertheless, the flexural strength and the flexural modulus reach the highest values for the PHB PCL blends containing 25 wt% PCL, with a remarkable decrease over this composition. The analysis of fractured surfaces by field emission scanning electron microscopy and thermal properties obtained by differential scanning calorimetry (DSC) and TGA give clear evidences of the immiscibility of these two biodegradable polymers. Additionally, DSC results showed an increase in crystallinity of both PHB and PCL with regard to individual polymers for PHB PCL blends containing 25 wt% PCL. Furthermore, an increase in the degradation onset (T0) of about 30 C higher was detected for the same blends. Dynamic mechanical thermal analysis showed slightly shifted glass transition temperatures of each individual polymer, thus indicating that although both PHB and PCL are not fully miscible, some interactions between them occur., This research was supported by the Ministry of Economy and Competitiveness-MINECO, Ref: MAT2014-59242-C2-1-R. The authors also thank the "Conselleria d'Educacio, Cultura i Esport"-Generalitat Valenciana, Ref: GV/2014/008 for financial support. D. Garcia-Garcia thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU Grant (FPU13/06011).

Electrospun hybrid scaffolds are an effective platform to deliver drugs site specifically for the prevention and treatment of diseases in addition to promote tissue regeneration because of the flexibility to load drugs therein. In the present study, electrospun hybrid scaffolds containing antibiotics were developed to support cellular activities and eliminate potential postoperative inflammation and infection. As a model drug, levofloxacin (LFX) was successfully incorporated into pure polyhydroxybutyrate/poly(epsilon-caprolactone) (PHB/PCL) scaffolds and PHB/PCL/sol-gel-derived silica (SGS) scaffolds. The influence of LFX on the morphology, mechanical performance, chemical structure, drug release profile, and antibacterial effect of the scaffolds was thoroughly and comparatively investigated. MG-63 osteoblast-like cell cultivation on both scaffolds certified that LFX inclusion did not impair the biocompatibility. In addition to the favorable cellular proliferation and differentiation, scaffolds containing both LFX and SGS displayed highly increased mineralization content. Therefore, the present multifunctional hybrid scaffolds are promising in tissue engineering applications.

Biodegradable polymers with antibacterial properties are highly desirable materials for active food packaging applications. Thymol, a dietary monoterpene phenol with a strong antibacterial activity is abundant in plants belonging to the genus Thymus. This study presents two approaches for supercritical CO2 impregnation of poly(lactic acid)(PLA)/poly(e-caprolactone)(PCL) blended films to induce antibacterial properties of the material: (i) a batch impregnation process for loading pure thymol, and (ii) an integrated supercritical extraction-impregnation process for isolation of thyme extract and its incorporation into the films, operated in both batch or semi-continuous modes with supercritical solution circulation. The PCL content in films, impregnation time and CO2 flow regime were varied to maximize loading of the films with thymol or thyme extract with preserving films' structure and thermal stability. Representative film samples impregnated with thymol and thyme extract were tested against Gram (−) (Escherichia coli) and Gram(+) (Bacillus subtilis) model strains, by measuring their metabolic activity and re-cultivation after exposure to the films. The film containing thymol (35.8 wt%) showed a strong antibacterial activity leading to a total reduction of bacterial cell viability. Proposed processes enable fast, controlled and organic solvent-free fabrication of the PLA/PCL films containing natural antibacterial substances at moderately low temperature, with a compact structure and a good thermal stability, for potential use as active food packaging materials.

Şahin, Yeşim Müge (Arel Author), In this study, poly (e-caprolactone) (PCL) and fish sarcoplasmic protein (FSP) (Mw < 200 kDa) composite nanofibers were fabricated by electrospinning technique. Solution properties such as density, viscosity, conductivity and surface tension were studied as a function of FSP content in the solution. The morphology, molecular interaction, degradation as well as thermal and tensile properties of PCL/FSP nanofibers were investigated. The results show that smooth and beadless PCL/FSP nanofibers with the diameters ranging from 120 +/- 29 nm to 139 +/- 41 nm were obtained. The average diameters decreased and the diameter distributions narrowed with the addition of optimum FSP amount. The characteristic picks of FSP and PCL were identified in the composite nanofibers by structural analyses. PCL/FSP nanofibers exhibited high degradation ability in comparison to electrospun pure PCL nancifibers. Moreover, the PCL/FSP nanofibers exhibit good mechanical properties (tensile strength of 5.55 MPa) with the additional FSP content. (C) 2017 Elsevier Ltd. All rights reserved.

WOS: 000459957400006 The synthesis of poly(epichlorohydrin-g-epsilon-caprolactone) [poly(ECH-g-CL)] graft copolymers were carried out by use of a "click" chemistry reaction to graft poly(epsilon-caprolactone) propargyl (PCL-propargyl) to poly(epichlorohydrin) azido (PECH-N-3). For this purpose, PECH-N-3 was synthesized by the reaction of poly(epichlorohydrin) and sodium azide. Then PCL-propargyl was obtained by the reaction of poly(epsilon-caprolactone) [PCL] and propargyl chloride. By reacting PECH-N-3 and PCL-propargyl, graft copolymers were obtained. The primary parameters, such as time and concentration, that influenced the reactions were assessed. The characterization of products was accomplished by using multiple instruments and methods including H-1-NMR, C-13-NMR, FT-IR, GPC, DSC, TGA, and fractional precipitation [non-solvent (petroleum ether, mL) /solvent (THF, mL)] techniques. Scientific and Technological Research Council of Turkey (TUBYTAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Giresun University Scientific Research FundGiresun University [FEN-BAP-A-160317-51] This work was supported by the Scientific and Technological Research Council of Turkey (TUBYTAK) (2229-International Post-Doctoral Research Fellowship Program) and partially supported by Giresun University Scientific Research Fund (grand number: FEN-BAP-A-160317-51).

In this paper, the preparation of PBS-ran-PCL copolyesters by enzymatic ring opening polymerization is presented for the first time. The copolyesters were produced in a wide composition range and free of metallic contaminants, so they may be regarded as potential biomaterials. The copolymers have been characterized by proton and carbon nuclear magnetic resonance (H and C NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM) and wide angle X-ray scattering (WAXS). The PBS-ran-PCL copolyesters were able to crystallize in the entire composition range and displayed a pseudo-eutectic region. Most copolymers away from the pseudo-eutectic region exhibited a single crystalline phase (PBS-rich or PCL-rich crystalline phase), while within the pseudo-eutectic region the copolymers were double crystalline. Observations by PLOM, during isothermal crystallization showed that both nucleation density and spherulitic growth rate of the copolyesters are determined by the component that constitutes the majority phase. WAXS studies revealed that d spacings of selected crystallographic planes depend on composition. Therefore, both DSC and WAXS results suggest that the copolymers are probably isodimorphic, as the PBS-rich crystalline phase may contain small inclusions of PCL co-units, while the PCL-rich crystalline domains may also contain a minor quantity of PBS co-units inside., This work received financial support from Ministerio de Economia y Competitividad (MINECO) of Spain with Grant MAT2012-38044-C03-03 and MAT2016-77345-C3-1-P and from Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) (Catalonia, Spain) with grant 2009SGR1469. The POLYMAT/UPV/EHU team would like to acknowledge funding from the following projects: “UPV/EHU Infrastructure: INF 14/38”; “MINECO/FEDER: SINF 130I001726XV1/Ref.: UNPV13-4E-1726” and “MINECO MAT2014-53437-C2-P”. A.A. and A.I. acknowledge financial support from the Spanish Ministry (MINECO), Ref: MAT2015-63704-P (MINECO/FEDER, UE) and by the Eusko Jaurlaritza (Basque Government), Ref: IT-654-13. C.C. wishes to acknowledge CNPq (National Research Council) Brazil for the financial support. M.S. gratefully acknowledges the award of a PhD fellowship by POLYMAT Basque Center for Macromolecular Design and Engineering. JC M-H thanks to Consejo Nacional de Ciencia y Tecnología (CONACYT) (Mexico) for the awarded PhD grant.

A profound understanding of how to tailor surface topographies of electrospun fibers is of great importance for surface sensitive applications including optical sensing, catalysis, drug delivery and tissue engineering. Hereby, a novel approach to comprehend the driving forces for fiber surface topography formation is introduced through inclusion of the dynamic solvent-polymer interaction during fiber formation. Thus, the interplay between polymer solubility as well as computed fiber jet surface temperature changes in function of time during solvent evaporation and the resultant phase separation behavior are studied. The correlation of experimental and theoretical results shows that the temperature difference between the polymer solution jet surface temperature and the dew point of the controlled electrospinning environment are the main influencing factors with respect to water condensation and thus phase separation leading to the final fiber surface topography. As polymer matrices with enhanced surface area are particularly appealing for sensing applications, we further functionalized our nanoporous fibrous membranes with a phosphorescent oxygen-sensitive dye. The hybrid membranes possess high brightness, stability in aqueous medium, linear response to oxygen and hence represent a promising scaffold for cell growth, contactless monitoring of oxygen and live fluorescence imaging in 3-D cell models.

Poly(epsilon-caprolactone) (PCL) particles were prepared by physicochemical method with solvent/non-solvent systems. The synthetic polymer polyvinylpyrrolidone (PVP) and natural polymer poly(alpha,gamma,L-glutamic acid) (PGA), were used as stabilizers and their influence on size and morphology of the particles was examined. The results were compared with those obtained without the use of stabilizers. This study evaluated, for the first time, PGA as stabilizer of PCL particles and demonstrated that PGA is more efficient stabilizer of PCL particles than most commonly used PVP. The particles obtained by using PGA as stabilizer were spherical, with smooth surfaces and dimensions below 1 mu m. The drying conditions were also varied in order to examine their influence on the formation of PCL particles. The samples were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, particle size distribution (DLS) and zeta potential measurements.

Three-dimensional (3D) printed poly(ε-caprolactone) (PCL) based scaffolds have being proposed for different tissue engineering applications. This study addresses the design and fabrication of 3D PCL constructs with different struts alignments at 90°, 45° and 90° with offset. The morphology and the mechanical behavior under uniaxial compressive load were assessed at different strain percentages. The combination of a new compressionCT device and micro computed tomography (micro-CT) allowed understanding the influence of pore geometry under controlled compressive strain in the mechanical and structural behavior of PCL constructs. Finite element analysis (FEA) was applied using the micro-CT data to modulate the mechanical response and compare with the conventional uniaxial compression tests. Scanning electron microscopic analysis showed a very high level of reproducibility and a low error comparing with the theoretical values, confirming that the alignment and the dimensional features of the printed struts are reliable. The mechanical tests showed that the 90° architecture presented the highest stiffness. With the compressionCT device was observed that the 90° and 90° with offset architectures presented similar values of porosity at same strain and similar pore size, contrary to the 45° architecture. Thus, pore geometric configurations affected significantly the deformability of the all PCL scaffolds under compression. The prediction of the FEA showed a good agreement to the conventional mechanical tests revealing the areas more affected under compression load. The methodology proposed in this study using 3D printed scaffolds with compressionCT device and FEA is a framework that offers great potential in understanding the mechanical and structural behavior of soft systems for different applications, including for the biomedical engineering field., The author Fernandes E M acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) and 'Programa Operacional Potencial Humano-POPH' and 'Fundo Social Europeu-FSE' for the post-doctoral grant (SFRH/BPD/96197/2013)., info:eu-repo/semantics/publishedVersion

Poly(epsilon-caprolactone) (PCL) based nanocomposites with unmodified and organomodified sepiolites were prepared by solution casting method. The sepiolites were modified with short (3-mercaptopropyl)trimethoxysilane (SEP-SI) by using covalent grafting or with long hexadecylamine (SEP-HDA) by using ionic exchange. In order to reveal the influence of the organomodification on the nanoclay dispersion and the properties of the nano composites XRD, DSC, TG, SEM, TEM, optical microscopy, melt rheology and dynamic-mechanical analyses were performed. A better dispersion was achieved when organomodified sepiolites instead of native ones were used as fillers. As deduced from the melt rheology data, by analysis of the Cole-Cole plots, the best dispersion was obtained for SEP-SI nanoclay. The thermal stability was not improved, however in the initial stages of the thereto-oxidative degradation a delay in the weight loss was observed for nanocomposites with organomodified sepiolites. The mechanical properties of the nanocomposites were improved in comparison to PCL, particularly for those with modified sepiolites. In terms of mechanical properties the use of sepiolite modified with HDA gave the best results, as a consequence of better interaction between longer alkyl hydrophobic part of the organic modificator and the hydrophobic PCL matrix. This is a peer-reviewed version of the article [https://doi.org/10.1016/j.eurpolymj.2017.10.010] [http://cer.ihtm.bg.ac.rs/handle/123456789/2104]

The delivery of therapeutic ions, as a key element for the regeneration of soft tissue, represents a viable alternative to conventional drugs. Primarily designed for the regeneration of hard tissue, degradable bioactive inorganic matrices are a carrier of choice for the delivery of ionic chemical cues. However, they nucleate calcium-phosphate crystal on their surface, which could be undesired for most soft tissue regeneration. Here, a coaxial electrospinning process was engineered, generating core–shell fibres with inorganic particles enclosed within a bio-inert polymeric shell. Silicon doped vaterite (SiV) dispersed in poly(L-lactic acid) was selected as an inorganic composite core and poly(D,L-lactide-co-glycolide) (PLGA) as a shell. By careful selection of the electrospinning parameters, fibres of constant diameter (≈10 μm) with controllable shell thickness (from 1.3 to 4.2 μm) were obtained. The release of calcium and silica followed the Weibull model, showing a purely diffusive release after hydration of the PLGA layer. The rate of release could be controlled with the shell thickness. The nucleation of calcium-phosphate crystals was inhibited. In addition, with the presence of a PLGA shell layer, the mechanical properties of the fibermats were greatly improved with, for instance, an increase of the Young's modulus up to 536% as compared to original composite. These non-woven porous materials are an affordable investigation platform to study the effect of local ionic release onto the surrounding cell metabolism.

[EN] Reinforced poly(e-caprolactone) (PCL)/almond skin (AS) biocomposites were prepared by extrusion and injection moulding at different AS contents (0, 10, 20, 30 wt%) in order to revalorize this agricultural residue. AS particles were characterized by field emission scanning electron microscopy (FESEM), attenuated total reflectance infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). Hemicelluloses were the first compound thermally degraded (263 +/- 2 degrees C) followed by cellulose (330 +/- 5 degrees C) and lignin (401 +/- 3 degrees C) with a remaining residue of 20% which was associated to the fibre content present in AS. Mechanical, morphological, thermal, and water absorption properties; and enzymatic degradation using Pseudomonas lipase were evaluated for the obtained biocomposites. A significant improvement in Young's modulus with a gain of 73% at 30 wt% AS loading was obtained compared to neat PCL An increase in Shore D hardness and decrease in elongation at break and impact energy were also observed with increasing AS content caused by the reinforcement effect. Lower DSC thermal enthalpies and higher crystallinity were obtained for the biocomposites. Some decrease in thermal stability and higher water absorption values were also found with AS addition. Finally, the presence of AS retarded the enzymatic degradation of PCL, showing neat PCL higher weight loss after 25 days of study followed by PCL with 10 wt% AS. (C) 2016 Elsevier Ltd. All rights reserved., Authors would like to thank "Almendras Llopis S.A" for kindly providing the almond skin by-products as well as to Spanish Ministry of Economy and Competitiveness for financial support (MAT 2015-59242-C2-2-R). A. Valdes acknowledges Conselleria de Educacion (Spain) for ACIF/2010/172 Predoctoral Research Training Grant.

In view of the potential technological impact of solid polymer electrolytes (SPEs) in the domain of solid-state electrochemistry, particularly in the production of advanced batteries, sensors and electrochromic and photoelectrochemical devices, the sub-class of SPE materials has attracted considerable interest during the last two decades. Li+-doped ormolyte systems obtained using the sol-gel method has been investigated in the last few years. In this study we have used conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis to characterize an electrolyte system based on a lithium perchlorate (LiClO4)-doped di-urethane cross-linked poly(ε-caprolactone)(PCL)/siloxane hybrid matrix. The PCL/siloxane host hybrid matrix represents an attractive alternative, as it is expected to have lower environmental impact than electrolytes currently used in commercial devices. The biocompatible, biodegradable and air-permeable properties of the PCL matrix have led to extensive application of this material in the manufacture of suture cord, artificial skin, re-sorbable prosthetic devices and as a container for drug delivery. The amorphous hybrid materials characterized in this study combine acceptable levels of ionic conductivity (9.58x10-6 and 2.53x10-4 S.cm-1 at 25 and 90 °C, respectively) with low environmental impact. The authors of a previous publication, have concluded that organic-inorganic systems based on poly(ε-caprolactone) may be used as dual-function electrolyte/adhesive component in prototype solid-state electrochromic devices. This component provides significant advantages in optical performance, cycle lifetime and durability of the electrochromic devices relative to conventional liquid electrolytes., Fundação para a Ciência e a Tecnologia (FCT)

International audience; Two types of biodegradable poly(epsilon-caprolactone (CLo))-co-poly(epsilon caprolactam (CLa)) copolymers were prepared by catalyzed hydrolytic ring-opening polymerization For the first type of materials the respective cyclic comonomers were added simultaneously in the reaction medium leading to the formation of copolymers having a random distribution of co-units within the polyesteramide sequence as evidenced by H-1 and C-13 NMR For the second type of copolymers the cyclic comonomers were added sequentially in the reaction medium yielding diblock polyesteramides again evidenced by NMR The thermal and thermo-mechanical properties of the copolymers were investigated by DSC and DMA and correlated with the copolymer topology and composition The copolymers were char acterized by a storage modulus and alpha transition temperature intermediate to the modulus and T-g of the corresponding homopolymers The chemical composition and molecular weight of the copolymers proved to have only a limited effect on the thermo-mechanical properties of the materials The hydrolytic degradation of random copolymers was studied in a phosphate buffer at 60 degrees C and discussed in terms of chemical composition and molecular weight of the copolymers

International audience; Chemical modification of EVOH in the molten state at 185 degrees C by a grafting from process of poly(epsilon-caprolactone) in batch was studied. (1)H NMR was used to characterize the structure evolutions of PCL grafts. In addition to grafting reactions, dynamic covalent transesterification reactions between EVOH residual alcohols and the polyester grafts led to a redistribution of the PCL grafts length. (Dp) over bar (n) up to 27 and SR up to 80% were obtained. Experiments made in a corotating mini twin-screw extruder also confirmed these results. The effect of the alcohol to caprolactone ratio and catalyst concentration (SnOct(2)) on kinetic evolution showed that few minutes were necessary to complete the polymerization. A kinetic model was proposed and adequate conditions for the synthesis by reactive extrusion were defined.

International audience; EVOH-g-PCL were prepared by a solvent-free reactive extrusion process using a co-rotating twin screw extruder. Kinetic simulations were made of selected reaction conditions at 185 degrees C. Changes in the screw rotation rate resulted in evolution of the residence time distribution and slightly changed the monomer conversion. An increase of the [OH](0)/[Cl](0) ratio made the reactive system more viscous and decreased the overall pumping capacities of the extruder. Increase of the mean residence time, combined with a positive kinetic effect of [OH](0) increase, leaded to an important increase in conversion. For all the conducted experiments, equivalent distribution dispersions and good agreements between calculated conversion and those measured were obtained. An increase in temperature from 185 to 200 degrees C resulted in total conversion.

The ability to control the architecture and strength of a bone tissue engineering scaffold is critical to achieve a harmony between the scaffold and the host tissue. Rapid prototyping (RP) technique is applied to tissue engineering to satisfy this need and to create a scaffold directly from the scanned and digitized image of the defect site. Design and construction of complex structures with different shapes and sizes, at micro and macro scale, with fully interconnected pore structure and appropriate mechanical properties are possible by using RP techniques. In this study, RP was used for the production of poly(e-caprolactone) (PCL) scaffolds. Scaffolds with four different architectures were produced by using different configurations of the fibers (basic, basic-offset, crossed and crossed-offset) within the architecture of the scaffold. The structure of the prepared scaffolds were examined by scanning electron microscopy (SEM), porosity and its distribution were analyzed by micro-computed tomography (μ-CT), stiffness and modulus values were determined by dynamic mechanical analysis (DMA). It was observed that the scaffolds had very ordered structures with mean porosities about 60%, and having storage modulus values about 1 x 10 7 Pa. These structures were then seeded with rat bone marrow origin mesenchymal stem cells (MSCs) in order to investigate the effect of scaffold structure on the cell behavior; the proliferation and differentiation of the cells on the scaffolds were studied. It was observed that cell proliferation was higher on offset scaffolds (262000 vs 235000 for basic, 287000 vs 222000 for crossed structure) and stainings for actin filaments of the cells reveal successful attachment and spreading at the surfaces of the fibers. Alkaline phosphatase (ALP) activity results were higher for the samples with lower cell proliferation, as expected. Highest MSC differentiation was observed for crossed scaffolds indicating the influence of scaffold structure on cellular activities.

In the present study, a Raman line-imaging setup was employed to monitor in situ the CO2 sorption at,elevated pressures (from 042 to 7.10 MPa) in molten PCL. The method allowed the quantitative measurement of gas concentration in both the time -resolved and the space -resolved modes. The combined experimental and theoretical approach allowed a molecular level characterization of the system. The dissolved CO2 was found to occupy, a volume essentially coincident with its van der Waals volume and the estimated partial molar volume of the probe did not change with pressure. Lewis acid Lewis base interactions with the PCL Carbonyls was confirmed to be the main interaction mechanism. The geometry of the suptamolecular complex and the preferential interaction.site were controlled more by,steric than electronic effects. On the basis ofthe indications emerging from-Raman spectroscopy, an equation of state thermodynamic model for the PCL-CO2 system, based upon a compressible lattice fluid theory endowed with-specific interactions, has been tailored to account for the interaction types.detected spectroscopically. The predictions of the thermodynamic model in terms of molar volume of solution have been compared with available volumetric measurements while predictions for CO2 partial molar volume have been compared with the values estimated- on the basis of Raman spectroscopy

The electrospinning technique is a versatile method for the production of fibrous scaffolds able to resemble the morphology of the native extra cellular matrix. In the present paper, electrospinning is used to fabricate novel SiO2 particles (type MCM-41) containing poly(epsilon-caprolactone) (PCL) fibers. The main aims of the present work are both the optimization of the particle synthesis and the fabrication of composite fibers, obtained using benign solvents, suitable as drug delivery systems and scaffolds for soft tissue engineering applications. The optimized synthesis and characterization of calcium-containing MCM-41 particles are reported. Homogeneous bead-free composite electrospun mats were obtained by using acetic acid and formic acid as solvents; neat PCL electrospun mats were used as control. Initially, an optimization of the electrospinning environmental parameters, like relative humidity, was performed. The obtained composite nanofibers were characterized from the morphological, chemical and mechanical points of view, the acellular bioactivity of the composite nanofibers was also investigated. Positive results were obtained in terms of mesoporous particle incorporation in the fibers and no significant differences in terms of average fiber diameter were detected between the neat and composite electrospun fibers. Even if the Ca-containing MCM-41 particles are bioactive, this property is not preserved in the composite fibers. In fact, during the bioactivity assessment, the particles were released confirming the potential application of the composite fibers as a drug delivery system. Preliminary in vitro tests with bone marrow stromal cells were performed to investigate cell adhesion on the fabricated composite mats, the positive obtained results confirmed the suitability of the composite fibers as scaffolds for soft tissue engineering.

The objective of the present investigation was to assess the potential of magnesium oxide nanoparticle (MgO NP)-loaded electrospun polycaprolactone (PCL) polymer composites as a bone-soft tissue engineering scaffold. MgO NPs were synthesized using a hydroxide precipitation sol-gel method and characterized using field emission gun-scanning electron microscopy/energy-dispersive x-ray spectroscopy (FEG-SEM/EDS), field emission gun-transmission electron microscopy (FEG-TEM), and x-ray diffraction (XRD) analysis. PCL and MgO-PCL nanocomposite fibers were fabricated using electrospinning with trifluoroethanol as solvent at 19 kV applied voltage and 1.9 ml h-1 flow rate as optimized process parameters, and were characterized by FEG-TEM, FEG-SEM/EDS, XRD, and differential scanning calorimetry analyses. Characterization studies of as-synthesized nanoparticles revealed diffraction peaks indexed to various crystalline planes peculiar to MgO particles with hexagonal and cubical shape, and 40-60 nm size range. Significant improvement in mechanical properties (tensile strength and elastic modulus) of nanocomposites was observed as compared to neat polymer specimens (fourfold and threefold, respectively), due to uniform dispersion of nanofillers along the polymer fiber length. There was a remarkable bioactivity shown by nanocomposite scaffolds in immersion test, as indicated by formation of surface hydroxyapatite layer by the third day of incubation. MgO-loaded electrospun PCL mats showed enhanced in-vitro biological performance with osteoblast-like MG-63 cells in terms of adhesion, proliferation, and marked differentiation marker activity owing to greater surface roughness, nanotopography, and hydrophilicity facilitating higher protein adsorption. In-vivo subcutaneous implantation study in Sprague Dawley rats revealed initial moderate inflammatory tissue response near implant site at the second week timepoint that subsided later (eighth week) with no adverse effect on vital organ functionalities as seen in histopathological analysis supported by serum biochemical and hematological parameters which did not deviate significantly from normal physiological range, indicating good biocompatibility in-vivo. Thus, MgO-PCL nanocomposite electrospun fibers have potential as an efficient scaffold material for bone-soft tissue engineering applications.

[EN] In the present study, we examined the potential of using highly porous poly(epsilon-caprolactone) (PCL)-coated hydroxyapatite (HAp) scaffold derived from cuttlefish bone for bone tissue engineering applications. The cell culture studies were performed in vitro with preosteoblastic MC3T3-E1 cells in static culture conditions. Comparisons were made with uncoated HAp scaffold. The attachment and spreading of preosteoblasts on scaffolds were observed by Live/Dead staining Kit. The cells grown on the HAp/PCL composite scaffold exhibited greater spreading than cells grown on the HAp scaffold. DNA quantification and scanning electron microscopy (SEM) confirmed a good proliferation of cells on the scaffolds. DNA content on the HAp/PCL scaffold was significantly higher compared to porous HAp scaffolds. The amount of collagen synthesis was determined using a hydroxyproline assay. The osteoblastic differentiation of the cells was evaluated by determining alkaline phosphatase (ALP) activity and collagen type I secretion. Furthermore, cell spreading and cell proliferation within scaffolds were observed using a fluorescence microscope. (C) 2014 Elsevier B.V. All rights reserved., The financial support of the Ministry of Science, Education and Sports of the Republic of Croatia (Project 125-1252970-3005: "Bioceramic, Polymer and Composite Nanostructured Materials"), the Spanish Ministry project DPI2010-20399-C04-03 and the L'Oreal ADRIA-UNESCO national fellowship program for Women in Science is gratefully acknowledged.

Enoxaparin-immobilized gelatin/poly(ε-caprolactone) (PCL) or Eudragit® RS230D nanogels in the presence of tetraethyl orthosilicate (TEOS) as polycondensation reagent were designed and characterized for their sustained drug delivery ability. Enoxaparin (anti-Xa 1000 UI/mL) was used as a model drug at different concentrations (300, 500, and 1000 UI/mL). The resulting nanogels were prepared using sol-gel technique and analyzed using several analytical tools such as: thermal analysis (DSC and TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning and transmitting electron microscopes (SEM and TEM). In addition to particle size, zeta potential and in vitro release profiles were also investigated. A burst effect was observed, afterwards, the release rate became steady. The immobilization of enoxaparin into the gel network led to the formation of stable nanogels with ionic functional groups, which enable the efficient loading and sustainable release. The preliminary results showed that enoxaparin-immobilized PCL-based nanogels in this study can be utilized in the design of a sustained delivery system.

The stability of PCL/TiO2 nanocomposites under different environments was investigated. Samples were exposed to UV radiation in an accelerated weathering chamber equipment and characterized by viscosimetry and differential scanning calorimetry. The results showed that the presence of nanoparticles containing titanium enhanced polymer chain scission during UV exposure. For all samples, the melting temperature and crystallinity increased along photodegradation time. The biodegradability, assessed by biochemical oxygen demand, increased as the amount of inorganic particles increased. However, the thermal stability and activation energy evaluated by thermogravimetric analysis decreased as the amount of inorganic nanoparticles increased, indicating that nanocomposites exhibited lower thermal stability., The authors acknowledge the financial support given by FCT through the project PTDC/AMB/73854/2006. FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centre, CQ/UM-PEst-C/QUI/UI0686/2011 and I3N-PEst-C/CTM/LA0025/2011 (FCOMP-01-0124-FEDER-022716).

Nanocomposites of poly(e-caprolactone) (PCL) and tungsten trioxide (WO3) were prepared by solvent casting using 5 and 10% of WO3 nanoparticles. The nanocomposites were characterized using several analytical techniques such as XRD, SEM, thermal analysis (TGA and DSC), spectroscopic methods (FTIR and UV/Vis) to gather information on the modifications introduced by WO3. Photodegradation of PCL/WO3 nanocomposites was studied exposing the samples to a Xenon lamp, which simulates the UV spectrum of the sun. The results obtained showed that due to the incorporation of WO3 nanoparticles, the nanocomposites exhibit higher thermal stability together with higher photodegradation efficiency.

International audience; Poly(lactic acid) (PLA) is a biodegradable aliphatic polyester well suited for disposable applications. PLA was plasticized with various biocompatible plasticizers. Their efficiency was evaluated in terms of glass transition temperature (Tg) shift and mechanical properties improvement. Significant decrease in Tg and rise in the elongation at break was obtained with polyethylene glycol and oligomeric lactic acid. Furthermore, PLA was melt-blended with thermoplastic starch (TPS). The properties of subsequent TPS/PLA blends were investigated through tensile and impact testing, thermal analysis (DSC), dynamic mechanical analysis and microscopy (SEM). From the mechanical results, low level of compatibility was found. The blends showed two distinct Tgs. However, the PLA phase varied toward the Tg of TPS with the blend composition, indicating some degree of interaction. Microscopic observations revealed non-uniformly dispersed PLA inclusions in the TPS matrix, confirming that phase separation has occurred.

Electrospinning of a segmented copolymer having polyglycolide hard segments is successfully performed from 1,1,1,3,3,3-hexafluoroisopropanol solutions. During the process, a bactericidal agent, i.e., chlorhexidine (CHX), is effectively loaded, which results in nanofibers with a smaller diameter because of the change in solution conductivity. New fabrics based on molding of alternate layers of poly(e-caprolactone) (PCL) films and the electrospun scaffolds of the segmented copolymer are prepared and characterized. The thermal molding process renders a PCL matrix homogeneously reinforced with nanofibers that compensate for the loss of mechanical properties caused by incorporation of CHX. Release of CHX is evaluated in different media. Results vary depending on the layer where the drug is incorporated. Thus, systems with an immediate bacteriostatic effect, as well as systems with a potential long term antimicrobial effect, are obtained. Growth inhibition and adhesion assays demonstrate the fast bactericidal effect of samples with CHX loaded in its outer layers.