Surface charge mediated cell-surface interaction on piezoelectric materials

Cell–material interactions play an essential role in the development of scaffold-based tissue engineering strategies. Cell therapies are still limited in treating injuries when severe damage causes irreversible loss of muscle cells. Electroactive biomaterials and, in particular, piezoelectric materials offer new opportunities for skeletal muscle tissue engineering since these materials have demonstrated suitable electroactive microenvironments for tissue development. In this study, the influence of the surface charge of piezoelectric poly(vinylidene fluoride) (PVDF) on cell adhesion was investigated. The cytoskeletal organization of C2C12 myoblast cells grown on different PVDF samples was studied by immunofluorescence staining, and the interactions between single live cells and PVDF were analyzed using an atomic force microscopy (AFM) technique termed single-cell force spectroscopy. It was demonstrated that C2C12 myoblast cells seeded on samples with net surface charge present a more elongated morphology, this effect being dependent on the surface charge but independent of the poling direction (negative or positive surface charge). It was further shown that the cell deadhesion forces of individual C2C12 cells were higher on PVDF samples with an overall negative surface charge (8.92 ± 0.45 nN) compared to those on nonpoled substrates (zero overall surface charge) (4.06 ± 0.20 nN). These findings explicitly demonstrate that the polarization/surface charge is an important parameter to determine cell fate as it affects C2C12 cell adhesion, which in turn will influence cell behavior, namely, cell proliferation and differentiationPortuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019, UID/BIA/04050/2013, UID/BIO/04469, project POCI-01-0145-FEDER-028237 and under BioTecNorte operation (NORTE-01-0145-FEDER-000004). The authors also thank the FCT for the SFRH/BD/111478/2015 (S.R.) and SFRH/BPD/90870/2012 (C.R.) grants. Funds provided by FCT in the framework of EuroNanoMed 2016 call, Project LungChek ENMed/0049/2016 are also gratefully acknowledged. The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06

Influence of rGO on the Crystallization Kinetics, Cytoxicity, and Electrical and Mechanical Properties of Poly (L-lactide-co-ε-caprolactone) Scaffolds

Biodegradable scaffolds of poly (L-lactide-co-ε-caprolactone) (PLCL) and reduced graphene oxide (rGO) were prepared by TIPS (thermally induced phase separation). The nonisothermal cold crystallization kinetics were investigated by differential scanning calorimetry (DSC) with various cooling rates. The experimental values indicate that nonisothermal crystallization improves with cooling rate, but the increasing rGO concentration delays crystallization at higher temperatures. The activation energies were calculated by the Kissinger equation; the values were very similar for PLCL and for its compounds with rGO. The electrical conductivity measurements show that the addition of rGO leads to a rapid transition from insulating to conductive scaffolds with a percolation value of ≈0.4 w/w. Mechanical compression tests show that the addition of rGO improves the mechanical properties of porous substrates. In addition, it is an anisotropic material, especially at compositions of 1% w/w of rGO. All of the samples with different rGO content up to 1% are cytotoxic for C2C12 myoblast cells.This work was supported by the University of The Basque Center. The authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program. This work has been also supported by FCT–Fundação para a Ciência e Tecnologia (FCT) under the scope of the strategic funding of UID/FIS/04650/2020 and UIDB/04469/2020 units and project PTDC/BTM-MAT/28237/2017

The influence of copolymer composition on PLGA/nHA scaffolds´ cytotoxicity and in vitro degradation

The influence of copolymer composition on Poly(Lactide-co-Glycolide)/ nanohydroxyapatite (PLGA/nHA) composite scaffolds is studied in the context of bone tissue engineering and regenerative medicine. The composite scaffolds are fabricated by thermally-induced phase separation and the effect of bioactive nanoparticles on their in vitro degradation in phosphate-buffered solution at 37 °C is analyzed over eight weeks. The indirect cytotoxicity evaluation of the samples followed an adaptation of the ISO 10993-5 standard test method. Based on the measurement of their molecular weight, molar mass, pH, water absorption and dimensions, the porous scaffolds of PLGA with a lower lactide/glycolide (LA/GA) molar ratio degraded faster due to their higher hydrophilicity. All of the samples without and with HA are not cytotoxic, demonstrating their potential for tissue engineering applications.SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is really appreciated. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and Grant SFRH/BD/111478/2015 (S.R). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (Agencia Estatal de Investigación(AEI)/FEDER, Unión Europea(UE))info:eu-repo/semantics/publishedVersio

Ionic liquid-based materials for biomedical applications

Ionic liquids (ILs) have been extensively explored and implemented in different areas, ranging from sensors and actuators to the biomedical field. The increasing attention devoted to ILs centers on their unique properties and possible combination of different cations and anions, allowing the development of materials with specific functionalities and requirements for applications. Particularly for biomedical applications, ILs have been used for biomaterials preparation, improving dissolution and processability, and have been combined with natural and synthetic polymer matrixes to develop IL-polymer hybrid materials to be employed in different fields of the biomedical area. This review focus on recent advances concerning the role of ILs in the development of biomaterials and their combination with natural and synthetic polymers for different biomedical areas, including drug delivery, cancer therapy, tissue engineering, antimicrobial and antifungal agents, and biosensing.The authors thank the FCT (Fundacao para a Ciencia e Tecnologia) for financial support under the framework of the Strategic Funding UID/FIS/04650/2019 and pro-jects PTDC/BTM-MAT/28237/2017, PTDC/EMD-EMD/28159/2017, and PTDC/FIS-MAC/28157/2017. Funds provided by FCT in the framework of EuroNano-Med 2016 call, Project LungChek ENMed/0049/2016 are also gratefully acknowledged. D.M.C., L.C.F., R.M.M., and M.M.F. also thank the FCT for the grants SFRH/BPD/121526/2016, SFRH/BD/145345/2019, and FRH/BD/148655/2019, SFRH/BPD/121464/2016, respectively and CR thanks the FCT for the contract under the Stimulus of Scientific Employment (2020.04163.CEECIND). S.L.M. and J.R. acknowledge the funding support from the Spanish State Research Agency (AEI) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Department under the ELKARTEK program.info:eu-repo/semantics/publishedVersio

3D cytocompatible composites of PCL/Magnetite

A study of Magnetite (Fe3O4) as a suitable matrix for the improved adhesion and proliferation of MC3T3-E1 pre-osteoblast cells in bone regeneration is presented. Biodegradable and magnetic polycaprolactone (PCL)/magnetite (Fe3O4) scaffolds, which were fabricated by Thermally Induced Phase Separation, are likewise analyzed. Various techniques are used to investigate in vitro degradation at 37 °C, over 104 weeks, in a phosphate buffered saline (PBS) solution. Magnetic measurements that were performed at physiological temperature (310 K) indicated that degradation neither modified the nature nor the distribution of the magnetite nanoparticles. The coercive field strength of the porous matrices demonstrated ferromagnetic behavior and the probable presence of particle interactions. The added nanoparticles facilitated the absorption of PBS, with no considerable increase in matrix degradation rates, as shown by the Gel Permeation Chromatography (GPC) results for Mw, Mn, and I. There was no collapse of the scaffold structures that maintained their structural integrity. Their suitability for bone regeneration was also supported by the absence of matrix cytotoxicity in assays, even after additions of up to 20% magnetite.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK, HAZITEK and PIBA programs. Supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, project POCI-01-0145-FEDER-028237 and grant SFRH/BD/111478/2015 (S.R.) is acknowledged.Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully appreciated. The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Department under the ELKARTEK and HAZITEK and PIBA (PIBA-2018-06) programs. Supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, project POCI-01-0145-FEDER-028237 and grant SFRH/BD/111478/2015 (S.R.) is acknowledged

An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few “model species” on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change

A new approach for the fabrication of cytocompatible PLLA-magnetite nanoparticle composite scaffolds

Magnetic biomimetic scaffolds of poly(L-lactide) (PLLA) and nanoparticles of magnetite (nFe3O4) are prepared in a wide ratio of compositions by lyophilization for bone regeneration. The magnetic properties, cytotoxicity, and the in vitro degradation of these porous materials are closely studied. The addition of magnetite at 50 °C was found to produce an interaction reaction between the ester groups of the PLLA and the metallic cations of the magnetite, causing the formation of complexes. This fact was confirmed by the analysis of the infrared spectroscopy and the gel permeation chromatography test results. They, respectively, showed a displacement of the absorption bands of the carbonyl group (C=O) of the PLLA and a scission of the polymer chains. The iron from the magnetite acted as a catalyser of the macromolecular scission reaction, which determines the final biomedical applications of the scaffolds—it does so because the reaction shortens the degradation process without appearing to influence its toxicity. None of the samples studied in the tests presented cytotoxicity, even at 70% magnetite concentrations.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK, HAZITEK and PIBA programs. Supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, project POCI-01-0145-FEDER-028237 and grant SFRH/BD/111478/2015 (S.R.) is acknowledged

Development and evaluation of different electroactive poly(vinylidene fluoride) architectures for endothelial cell culture

Tissue engineering (TE) aims to develop structures that improve or even replace the biological functions of tissues and organs. Mechanical properties, physical-chemical characteristics, biocompatibility, and biological performance of the materials are essential factors for their applicability in TE. Poly(vinylidene fluoride) (PVDF) is a thermoplastic polymer that exhibits good mechanical properties, high biocompatibility and excellent thermal properties. However, PVDF structuring, and the corresponding processing methods used for its preparation are known to significantly influence these characteristics. In this study, doctor blade, salt-leaching, and electrospinning processing methods were used to produce PVDF-based structures in the form of films, porous membranes, and fiber scaffolds, respectively. These PVDF scaffolds were subjected to a variety of characterizations and analyses, including physicochemical analysis, contact angle measurement, cytotoxicity assessment and cell proliferation. All prepared PVDF scaffolds are characterized by a mechanical response typical of ductile materials. PVDF films displayed mostly vibration modes for the a-phase, while the remaining PVDF samples were characterized by a higher content of electroactive beta-phase due the low temperature solvent evaporation during processing. No significant variations have been observed between the different PVDF membranes with respect to the melting transition. In addition, all analysed PVDF samples present a hydrophobic behavior. On the other hand, cytotoxicity assays confirm that cell viability is maintained independently of the architecture and processing method. Finally, all the PVDF samples promote human umbilical vein endothelial cells (HUVECs) proliferation, being higher on the PVDF film and electrospun randomly-oriented membranes. These findings demonstrated the importance of PVDF topography on HUVEC behavior, which can be used for the design of vascular implants.This work has been partially funded by the Junta de Extremadura (Spain), the Spanish Ministry of Science and Innovation, the European Social Fund, the European Regional Development Fund, and the European Next Generation Funds (Grant Numbers PD18077, TA18023, and GR21201). The authors also thanks to Portuguese Foundation for Science and Technology (FCT) for financial support under grants SFRH/BD/140698/2018 (RP), 2020.04163. CEECIND (CR). The also authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID 2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program

Multifunctional platform based on electroactive polymers and silica nanoparticles for tissue engineering applications

Poly(vinylidene fluoride) nanocomposites processed with different morphologies, such as porous and non-porous films and fibres, have been prepared with silica nanoparticles (SiNPs) of varying diameter (17, 100, 160 and 300 nm), which in turn have encapsulated perylenediimide (PDI), a fluorescent molecule. The structural, morphological, optical, thermal, and mechanical properties of the nanocomposites, with SiNP filler concentration up to 16 wt %, were evaluated. Furthermore, cytotoxicity and cell proliferation studies were performed. All SiNPs are negatively charged independently of the pH and more stable from pH 5 upwards. The introduction of SiNPs within the polymer matrix increases the contact angle independently of the nanoparticle diameter. Moreover, the smallest ones (17 nm) also improve the PVDF Youngs modulus. The filler diameter, physico-chemical, thermal and mechanical properties of the polymer matrix were not significantly affected. Finally, the SiNPs inclusion does not induce cytotoxicity in murine myoblasts (C2C12) after 72 h of contact and proliferation studies reveal that the prepared composites represent a suitable platform for tissue engineering applications, as they allow us to combine the biocompatibility and piezoelectricity of the polymer with the possible functionalization and drug encapsulation and release of the SiNP.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) and project POCI-01-0145-FEDER-028237 funded by national funds through Fundação para a Ciência e a Tecnologia (FCT) and by the ERDF through the COMPETE2020-Programa Operacional Competitividade e Internacionalização (POCI); and also under the scope of the strategic funding of UID/BIO/04469 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte. The authors also thank the FCT for the SFRH/BD/111478/2015 (S.R.), SFRH/BPD/96707/2013 (T.R.), SFRH/BPD/90870/2012 (C.R.) and SFRH/BPD/121526/2016 (D.C) grants. The authors acknowledge funding from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively.info:eu-repo/semantics/publishedVersio

Funding research using climate change mitigation: The case of the Carbone boréal research infrastructure

Since 1988, the Intergovernmental Panel on Climate Change (IPCC) has gathered research and produced reports to inform decision makers on climate change. Among crosscutting topics, ecosystem management and nature-based solutions (NBS) have received growing attention as they are readily available and relatively inexpensive. NBS are part of the Agriculture, Forestry and Other Land Uses economical sector [1]. While carbon prices can reach up to USD100 t-1 CO2-eq, greenhouse gas (GHG) land-based mitigation can be achieved for less in agriculture (e.g. soil carbon management, agroforestry, soil biochar addition), forestry (e.g. afforestation, reforestation, decreased deforestation) and using other ecosystems (e.g. peatland and wetland restoration) [1]. NBS have the potential to reduce GHG emissions by 8–14 Gt CO2-eq yr-1 between 2020–2050 [1], which represents 32–82% of the emission gap by 2030 to limit global warming between 1.5–2°C by 2100 compared with the preindustrial era [2]. In addition to CO2 removal from the atmosphere, NBS also render valuable ecosystem services such as biodiversity conservation, water and nutrient cycling regulation and soil preservation [3–6]. Several positive impacts on human well-being and sustainable development goals can also be achieved through NBS [1]