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Polymers have gained a remarkable place in the biomedical fi eld as materials for the fabrication of various devices and for tissue engineering applications. The initial acceptance or rejection of an implantable device is dictated by the crosstalk of the material surface with the bioentities present in the physiological environment. Advances in microfabrication and nanotechnology offer new tools to investigate the complex signaling cascade induced by the components of the extracellular matrix and consequently allow cellular responses to be tailored through the mimicking of some elements of the signaling paths. Patterning methods and selective chemical modifi cation schemes at different length scales can provide biocompatible surfaces that control cellular interactions on the micrometer and sub-micrometer scales on which cells are organized. In this review, the potential of chemically and topographically structured micro- and nanopolymer surfaces are discussed in hopes of a better understanding of cell–biomaterial interactions, including the recent use of biomimetic approaches or stimuli-responsive macromolecules. Additionally, the focus will be on how the knowledge obtained using these surfaces can be incorporated to design biocompatible materials for various biomedical applications, such as tissue engineering, implants, cell-based biosensors, diagnostic systems, and basic cell biology. The review focusses on the research carried out during the last decade. ; The research leading to these results has received partial funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. NMP4-SL-2009-229292 and by the FCT projects PTDC/FIS/68517/2006, PTDC/QUI/69263/2006, PTDC/FIS/68209/2006, and ...

Layer-by-layer films based on chitosan and hyaluronic acid were produced by dip- and spin-coating techniques onto glass, 316L stainless steel and titanium. These natural polymers were modified with catechol groups, in order to build coatings with improved adhesive properties. Polymeric coatings were exclusively composed by both modified polymers whereas the multifunctional coatings combined an inorganic phase of bioactive glass nanoparticles with the polymeric layers to confer bioactivity. Ultraviolet-visible spectroscopy demonstrated that both polymers were successfully synthesized. Fourier transform infrared imaging was used as an innovative way to analyze the layer interdiffusion in these coatings. Their morphology was analyzed by scanning electron microscopy and atomic force microscopy, and their wettability was evaluated by water contact angle measurements. Major differences were found in the structure and surface properties of the coatings assembled either by dip- or spin-coating. The spin-coated films onto glass were smoother, with a more homogeneous structure and lower interdiffusion of polyelectrolytes layers, when compared with the dip-coated ones. Furthermore, it was concluded that the intrinsic surface roughness of stainless steel and titanium substrates had great influence on the surface morphology and wettability of the coatings obtained from both layer-by-layer methodologies. ; Portuguese Foundation for Science and Technology (FCT) and the European program FEDER/FEEI for the financial support through projects PTDC/BTM‐MAT/28123/2017 and PTDC/NAN‐MAT/31036/2017 and to the European Commission Horizon 2020 programme under the following grant agreements: 692333‐CHEM2NATURE, 668983‐FORECAST, and 739572‐THE DISCOVERIES CTR. The authors also acknowledge FCT for the financial support through the exploratory project MIT‐EXPL/BIO/0089/2017. This article has also been prepared with the support of REMIX Project, funded by the European Union's Horizon 2020 Research and Innovation programme under the Maria ...

The anterior cruciate ligament (ACL) is one of the most prone to injury in the human body. Due to its insufficient vascularization and low regenerative capacity, surgery is often required when it is ruptured. Most of the current tissue engineering (TE) strategies are based on scaffolds produced with fibers due to the natural ligamentâ s fibrous structure. In the present work, composite filaments based on poly(L-lactic acid) (PLA) reinforced with graphite nanoplatelets (PLA+EG) as received, chemically functionalized (PLA+f-EG), or functionalized and decorated with silver nanoparticles [PLA+((f-EG)+Ag)] were produced by melt mixing, ensuring good filler dispersion. These filaments were produced with diameters of 0.25 mm and 1.75 mm for textile-engineered and 3D-printed ligament scaffolds, respectively. The resulting composite filaments are thermally stable, and the incorporation of graphite increases the stiffness of the composites and decreases the electrical resistivity, as compared to PLA. None of the filaments suffered significant degradation after 27 days. The composite filaments were processed into 3D scaffolds with finely controlled dimensions and porosity by textile-engineered and additive fabrication techniques, demonstrating their potential for ligament TE applications. ; This research was funded by FCT through the National Funds Reference UIDB/05256/2020 and UIDP/05256/2020, the FCT and European Program FEDER/COMPETE through the project PTDC/BTM-MAT/28123/2017, and the FCT, European Union and European Social Fund (FSE) through the PhD Grant Reference ...

Aqueous extracts of commercially available red macroalgae Porphyra dioica were integrated as inner coatings of food-grade polypropylene (PP) films through use of electrospinning and electrospraying technologies. Two coating formulations (A = 5 wt% P. dioica extract and 7.5 wt% polyvinyl alcohol (PVA); B = 1 wt% P. dioica extract, 1 wt% PVA, and 17% gelatine) were evaluated as to their capacity to delay spoilage of minced chicken breasts, through monitoring of microbial growth (total mesophile aerobic colony counts), colour stability, lipid oxidation (thiobarbituric acid reactive substances (TBARS)), and sensory analysis over a 4-day refrigerated storage. Scanning electron microscopy (SEM) imaging revealed an increased nanofiber and nanoparticle density on extract-enriched fibers, without compromise to their morphology or the homogeneity of the coatings. Total microbial counts on coating B samples was significantly (p < 0.001) reduced compared to uncoated plastic wraps. The coated samples also exhibited fewer colour degradation, though the coatings did not di er substantially from uncoated plastic wrap. Sensory analysis test subjects successfully distinguished the raw samples based on their treatment and gave a positive approval rating (66.7%) to the extract-enriched coatings when asked about edibility post storage. ; This work was supported by the research project "i.FILM – Multifunctional Films for Intelligent and Active Applications" (nº 17921) cofounded by European Regional Development Fund (FEDER) through the Competitiveness and Internationalization Operational Program under the "Portugal 2020" Program, Call no. 33/SI/2015, Co-Promotion Projects and by the Integrated Programme of SR&TD "Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate" (reference Centro-01-0145-FEDER-000018), co-funded Coatings 2020, 10, 315 12 of 14 by Centro 2020 program, Portugal 2020, European Union, through the European Regional Development Fund. This work was also supported by the Fundação para a Ciência e a Tecnologia (FCT) and Centro2020 through the following Projects: UIDB/04044/2020, UIDP/04044/2020, PAMI - ROTEIRO/0328/2013 (Nº 022158) and MATIS (CENTRO-01-0145-FEDER-000014 - 3362). João Reboleira, Sara Guerreiro and Mariana Andrade are grateful for their research grant (2016/iFILM/BM) in the frame of iFILM project. Also, this study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2019 granted to MARE. ; info:eu-repo/semantics/publishedVersion

Chitosan (CHT)/poly(ε-caprolactone) (PCL) blend 3D fiber-mesh scaffolds were studied as possible support structures for articular cartilage tissue (ACT) repair. Micro-fibers were obtained by wet-spinning of three different polymeric solutions: 100:0 (100CHT), 75:25 (75CHT) and 50:50 (50CHT) wt.% CHT/PCL, using a common solvent solution of 100 vol.% of formic acid. Scanning electron microscopy (SEM) analysis showed a homogeneous surface distribution of PCL. PCL was well dispersed throughout the CHT phase as analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. The fibers were folded into cylindrical moulds and underwent a thermal treatment to obtain the scaffolds. μCT analysis revealed an adequate porosity, pore size and interconnectivity for tissue engineering applications. The PCL component led to a higher fiber surface roughness, decreased the scaffolds swelling ratio and increased their compressive mechanical properties. Biological assays were performed after culturing bovine articular chondrocytes up to 21 days. SEM analysis, live-dead and metabolic activity assays showed that cells attached, proliferated, and were metabolically active over all scaffolds formulations. Cartilaginous extracellular matrix (ECM) formation was observed in all formulations. The 75CHT scaffolds supported the most neo-cartilage formation, as demonstrated by an increase in glycosaminoglycan production. In contrast to 100CHT scaffolds, ECM was homogenously deposited on the 75CHT and 50CHT scaffolds. Although mechanical properties of the 50CHT scaffold were better, the 75CHT scaffold facilitated better neo-cartilage formation. ; The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number NMP4-SL-2009-229292 and it was also supported in part by a grant from the Dutch Program for Tissue Engineering (DPTE) to Liliana S. Moreira-Teixeira and Marcel ...