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Silva S, Barbosa JM, Sousa JD, Paiva MC, Teixeira PF. High-Performance PEEK/MWCNT Nanocomposites: Combining Enhanced Electrical Conductivity and Nanotube Dispersion. Polymers (Basel) 2024; 16:583. [PMID: 38475267 DOI: 10.3390/polym16050583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
High-performance engineering thermoplastics offer lightweight and excellent mechanical performance in a wide temperature range. Their composites with carbon nanotubes are expected to enhance mechanical performance, while providing thermal and electrical conductivity. These are interesting attributes that may endow additional functionalities to the nanocomposites. The present work investigates the optimal conditions to prepare polyether ether ketone (PEEK)/multi-walled carbon nanotube (MWCNT) nanocomposites, minimizing the MWCNT agglomerate size while maximizing the nanocomposite electrical conductivity. The aim is to achieve PEEK/MWCNT nanocomposites that are suitable for melt-spinning of electrically conductive multifilament's. Nanocomposites were prepared with compositions ranging from 0.5 to 7 wt.% MWCNT, showing an electrical percolation threshold between 1 and 2 wt.% MWCNT (107-102 S/cm) and a rheological percolation in the same range (1 to 2 wt.% MWCNT), confirming the formation of an MWCNT network in the nanocomposite. Considering the large drop in electrical conductivity typically observed during melt-spinning and the drawing of filaments, the composition PEEK/5 wt.% MWCNT was selected for further investigation. The effect of the melt extrusion parameters, namely screw speed, temperature, and throughput, was studied by evaluating the morphology of MWCNT agglomerates, the nanocomposite rheology, and electrical properties. It was observed that the combination of the higher values of screw speed and temperature profile leads to the smaller number of MWCNT agglomerates with smaller size, albeit at a slightly lower electrical conductivity. Generally, all processing conditions tested yielded nanocomposites with electrical conductivity in the range of 0.50-0.85 S/cm. The nanocomposite processed at higher temperature and screw speed presented the lowest value of elastic modulus, perhaps owing to higher matrix degradation and lower connectivity between the agglomerates. From all the process parameters studied, the screw speed was identified to have the higher impact on nanocomposite properties.
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Affiliation(s)
- Sofia Silva
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - José M Barbosa
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - João D Sousa
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - Maria C Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal
| | - Paulo F Teixeira
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
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Silva M, Gomes S, Correia C, Peixoto D, Vinhas A, Rodrigues MT, Gomes ME, Covas JA, Paiva MC, Alves NM. Biocompatible 3D-Printed Tendon/Ligament Scaffolds Based on Polylactic Acid/Graphite Nanoplatelet Composites. Nanomaterials (Basel) 2023; 13:2518. [PMID: 37764548 PMCID: PMC10536374 DOI: 10.3390/nano13182518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/29/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
Three-dimensional (3D) printing technology has become a popular tool to produce complex structures. It has great potential in the regenerative medicine field to produce customizable and reproducible scaffolds with high control of dimensions and porosity. This study was focused on the investigation of new biocompatible and biodegradable 3D-printed scaffolds with suitable mechanical properties to assist tendon and ligament regeneration. Polylactic acid (PLA) scaffolds were reinforced with 0.5 wt.% of functionalized graphite nanoplatelets decorated with silver nanoparticles ((f-EG)+Ag). The functionalization of graphene was carried out to strengthen the interface with the polymer. (f-EG)+Ag exhibited antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), an important feature for the healing process and prevention of bacterial infections. The scaffolds' structure, biodegradation, and mechanical properties were assessed to confirm their suitability for tendon and ligamentregeneration. All scaffolds exhibited surface nanoroughness created during printing, which was increased by the filler presence. The wet state dynamic mechanical analysis proved that the incorporation of reinforcement led to an increase in the storage modulus, compared with neat PLA. The cytotoxicity assays using L929 fibroblasts showed that the scaffolds were biocompatible. The PLA+[(f-EG)+Ag] scaffolds were also loaded with human tendon-derived cells and showed their capability to maintain the tenogenic commitment with an increase in the gene expression of specific tendon/ligament-related markers. The results demonstrate the potential application of these new 3D-printed nanocomposite scaffolds for tendon and ligament regeneration.
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Affiliation(s)
- Magda Silva
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (S.G.); (J.A.C.); (M.C.P.)
| | - Susana Gomes
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (S.G.); (J.A.C.); (M.C.P.)
| | - Cátia Correia
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Daniela Peixoto
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Adriana Vinhas
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Márcia T. Rodrigues
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Manuela E. Gomes
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - José A. Covas
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (S.G.); (J.A.C.); (M.C.P.)
| | - Maria C. Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (S.G.); (J.A.C.); (M.C.P.)
| | - Natália M. Alves
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4805-017 Guimarães, Portugal; (M.S.); (C.C.); (D.P.); (A.V.); (M.T.R.); (M.E.G.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
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Esteves DS, Pereira MFC, Ribeiro A, Durães N, Paiva MC, Sequeiros EW. Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning. Polymers (Basel) 2023; 15:2870. [PMID: 37447515 DOI: 10.3390/polym15132870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
The fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanotubes (MWCNTs) and magnetite particles in a polyurethane (PU) matrix to study the effect on the electrical resistance of electrodes produced under magnetic fields. Composites with 1 wt.% of MWCNT, 1 wt.% of magnetite and combinations of both were prepared and analysed. The hybrid composites combined MWCNTs and magnetite at the weight ratios of 1:1; 1:1/6; 1:1/12; and 1:1/24. The results showed that MWCNTs were responsible for the electrical conductivity of the composites since the composites with 1 wt.% magnetite were non-conductive. Combining magnetite particles with MWCNTs reduces the electrical resistance of the composite. SQUID analysis showed that MWCNTs simultaneously exhibit ferromagnetism and diamagnetism, ferromagnetism being dominant at lower magnetic fields and diamagnetism being dominant at higher fields. Conversely, magnetite particles present a ferromagnetic response much stronger than MWCNTs. Finally, optical microscopy (OM) and X-ray micro computed tomography (micro CT) identified the interaction between particles and their location inside the composite. In conclusion, the combination of magnetite and MWCNTs in a polymer composite allows for the control of the location of these particles using an external magnetic field, decreasing the electrical resistance of the electrodes produced. By adding 1 wt.% of magnetite to 1 wt.% of MWCNT (1:1), the electric resistance of the composites decreased from 9 × 104 to 5 × 103 Ω. This approach significantly improved the reproducibility of the electrode's fabrication process, enabling the development of a triboelectric sensor using a polyurethane (PU) composite and silicone rubber (SR). Finally, the method's bearing was demonstrated by developing an automated robotic soft grip with tendon-driven actuation controlled by the triboelectric sensor. The results indicate that magnetic patterning is a versatile and low-cost approach to manufacturing sensors for soft robotics.
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Affiliation(s)
- David Seixas Esteves
- Department of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
- CENTI, Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, Portugal
| | - Manuel F C Pereira
- CERENA, Center for Natural Resources and Environment, IST, University of Lisbon, 1049-001 Lisboa, Portugal
| | - Ana Ribeiro
- CENTI, Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, Portugal
| | - Nelson Durães
- CENTI, Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, Portugal
| | - Maria C Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal
| | - Elsa W Sequeiros
- Department of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
- INEGI-Institute of Science and Innovation in Mechanical and Industrial Engineering, 4200-465 Porto, Portugal
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Peixoto T, Carneiro S, Fangueiro R, Guedes RM, Paiva MC, Lopes MA. Engineering hybrid textile braids for tendon and ligament repair application. J Appl Polym Sci 2022. [DOI: 10.1002/app.52013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tânia Peixoto
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
- Instituto de Polímeros e Compósitos, Departamento de Engenharia de Polímeros Universidade do Minho Guimarães Portugal
| | - Sofia Carneiro
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
| | - Raúl Fangueiro
- Centro de Ciência e Tecnologia Têxtil Universidade do Minho Guimarães Portugal
| | - Rui M. Guedes
- INEGI, Departamento de Engenharia Mecânica, Faculdade de Engenharia Universidade do Porto Porto Portugal
| | - Maria C. Paiva
- Instituto de Polímeros e Compósitos, Departamento de Engenharia de Polímeros Universidade do Minho Guimarães Portugal
| | - Maria A. Lopes
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
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Peixoto T, Carneiro S, Pereira F, Santos C, Fangueiro R, Duarte I, Paiva MC, Lopes MA, Guedes RM. Hybrid structures for Achilles' tendon repair. POLYM ADVAN TECHNOL 2022. [DOI: 10.1002/pat.5693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tânia Peixoto
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
- Instituto de Polímeros e Compósitos, Departamento de Engenharia de Polímeros Universidade do Minho Guimarães Portugal
| | - Sofia Carneiro
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
| | - Fábio Pereira
- CITAB, Escola de Ciência e Tecnologia Universidade de Trás‐os‐Montes e Alto Douro Vila Real Portugal
| | - Cristóvão Santos
- LAETA – Laboratório Associado em Energia Transportes e Aeronáutica – INEGI Porto Portugal
| | - Raúl Fangueiro
- Centro de Ciência e Tecnologia Têxtil Universidade do Minho Guimarães Portugal
| | - Isabel Duarte
- Centro de Tecnologia Mecânica e Automação (TEMA), Departamento de Engenharia Mecânica Universidade de Aveiro Aveiro Portugal
| | - Maria C. Paiva
- Instituto de Polímeros e Compósitos, Departamento de Engenharia de Polímeros Universidade do Minho Guimarães Portugal
| | - Maria A. Lopes
- REQUIMTE‐LAQV, Departamento de Engenharia Metalúrgica e Materiais, Faculdade de Engenharia Universidade do Porto Porto Portugal
| | - Rui M. Guedes
- INEGI, Departamento de Engenharia Mecânica, Faculdade de Engenharia Universidade do Porto Porto Portugal
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Silva M, Gomes C, Pinho I, Gonçalves H, Vale AC, Covas JA, Alves NM, Paiva MC. Poly(Lactic Acid)/Graphite Nanoplatelet Nanocomposite Filaments for Ligament Scaffolds. Nanomaterials (Basel) 2021; 11:nano11112796. [PMID: 34835562 PMCID: PMC8625229 DOI: 10.3390/nano11112796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 01/15/2023]
Abstract
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 ligament'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.
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Affiliation(s)
- Magda Silva
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, Barco, 4805-017 Guimarães, Portugal; (M.S.); (A.C.V.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
| | - Carina Gomes
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
| | - Isabel Pinho
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
| | - Hugo Gonçalves
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
| | - Ana C. Vale
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, Barco, 4805-017 Guimarães, Portugal; (M.S.); (A.C.V.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - José A. Covas
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
| | - Natália M. Alves
- 3B’s Research Group, I3Bs—Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, Barco, 4805-017 Guimarães, Portugal; (M.S.); (A.C.V.)
- ICVS/3B’s, Associate PT Government Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
- Correspondence: (N.M.A.); (M.C.P.)
| | - Maria C. Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal; (C.G.); (I.P.); (H.G.); (J.A.C.)
- Correspondence: (N.M.A.); (M.C.P.)
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Dias D, Vale AC, Cunha EPF, C Paiva M, Reis RL, Vaquette C, Alves NM. 3D-printed cryomilled poly(ε-caprolactone)/graphene composite scaffolds for bone tissue regeneration. J Biomed Mater Res B Appl Biomater 2020; 109:961-972. [PMID: 33241654 DOI: 10.1002/jbm.b.34761] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/30/2020] [Accepted: 11/10/2020] [Indexed: 01/17/2023]
Abstract
In this study, composite scaffolds based on poly(caprolactone) (PCL) and non-covalently functionalized few-layer graphene (FLG) were manufactured by an extrusion-based system for the first time. For that, functionalized FLG powder was obtained through the evaporation of a functionalized FLG aqueous suspension prepared from a graphite precursor. Cryomilling was shown to be an efficient mixing method, producing a homogeneous dispersion of FLG particles onto the PCL polymeric matrix. Thereafter, fused deposition modeling (FDM) was used to print 3D scaffolds and their morphology, thermal, biodegradability, mechanical, and cytotoxicity properties were analysed. The presence of functionalized FLG demonstrated to induce slight changes in the microstructure of the scaffold, did not affect the thermal stability and enhanced significantly the compressive modulus. The composite scaffolds presented a porosity of around 40% and a mean pore size in the range of 300 μm. The cell viability and proliferation of SaOs-2 cells were assessed and the results showed good cell viability and long-term proliferation onto produced composite scaffolds. Therefore, these new FLG/PCL scaffolds comprised adequate morphological, thermal, mechanical, and biological properties to be used in bone tissue regeneration.
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Affiliation(s)
- Daniela Dias
- 3Bs Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.,ICVS/3B's, PT Associate Laboratory, Guimarães, Portugal
| | - Ana C Vale
- 3Bs Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.,ICVS/3B's, PT Associate Laboratory, Guimarães, Portugal
| | - Eunice P F Cunha
- Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, Guimarães, Portugal
| | - Maria C Paiva
- Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, Guimarães, Portugal
| | - Rui L Reis
- 3Bs Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.,ICVS/3B's, PT Associate Laboratory, Guimarães, Portugal
| | - Cedryck Vaquette
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Natália M Alves
- 3Bs Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.,ICVS/3B's, PT Associate Laboratory, Guimarães, Portugal
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8
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Teixeira MA, Paiva MC, Amorim MTP, Felgueiras HP. Electrospun Nanocomposites Containing Cellulose and Its Derivatives Modified with Specialized Biomolecules for an Enhanced Wound Healing. Nanomaterials (Basel) 2020; 10:E557. [PMID: 32204521 PMCID: PMC7153368 DOI: 10.3390/nano10030557] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/12/2020] [Accepted: 03/15/2020] [Indexed: 01/16/2023]
Abstract
Wound healing requires careful, directed, and effective therapies to prevent infections and accelerate tissue regeneration. In light of these demands, active biomolecules with antibacterial properties and/or healing capacities have been functionalized onto nanostructured polymeric dressings and their synergistic effect examined. In this work, various antibiotics, nanoparticles, and natural extract-derived products that were used in association with electrospun nanocomposites containing cellulose, cellulose acetate and different types of nanocellulose (cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose) have been reviewed. Renewable, natural-origin compounds are gaining more relevance each day as potential alternatives to synthetic materials, since the former undesirable footprints in biomedicine, the environment, and the ecosystems are reaching concerning levels. Therefore, cellulose and its derivatives have been the object of numerous biomedical studies, in which their biocompatibility, biodegradability, and, most importantly, sustainability and abundance, have been determinant. A complete overview of the recently produced cellulose-containing nanofibrous meshes for wound healing applications was provided. Moreover, the current challenges that are faced by cellulose acetate- and nanocellulose-containing wound dressing formulations, processed by electrospinning, were also enumerated.
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Affiliation(s)
- Marta A. Teixeira
- Centre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal; (M.A.T.); (M.T.P.A.)
| | - Maria C. Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites/i3N, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal;
| | - M. Teresa P. Amorim
- Centre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal; (M.A.T.); (M.T.P.A.)
| | - Helena P. Felgueiras
- Centre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal; (M.A.T.); (M.T.P.A.)
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Abstract
Ligaments and tendons are fibrous tissues with poor vascularity and limited regeneration capacity. Currently, a ligament/tendon injury often require a surgical procedure using auto- or allografts that present some limitations. These inadequacies combined with the significant economic and health impact have prompted the development of tissue engineering approaches. Several natural and synthetic biodegradable polymers as well as composites, blends and hybrids based on such materials have been used to produce tendon and ligament scaffolds. Given the complex structure of native tissues, the production of fiber-based scaffolds has been the preferred option for tendon/ligament tissue engineering. Electrospinning and several textile methods such as twisting, braiding and knitting have been used to produce these scaffolds. This review focuses on the developments achieved in the preparation of tendon/ligament scaffolds based on different biodegradable polymers. Several examples are overviewed and their processing methodologies, as well as their biological and mechanical performances, are discussed.
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Affiliation(s)
- Magda Silva
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark-Parque de Ciência e Tecnologia, Barco, 4805-017, Guimarães, Portugal
- ICVS/3B's, Associate PT Government Laboratory, Braga/Guimarães, Portugal
- Department of Polymer Engineering, Institute for Polymers and Composites/i3N, University of Minho, 4800-058, Guimarães, Portugal
- 2C2T-Centre of Textile Science and Technology, University of Minho, 4800-058, Guimarães, Portugal
| | - Fernando N Ferreira
- 2C2T-Centre of Textile Science and Technology, University of Minho, 4800-058, Guimarães, Portugal
| | - Natália M Alves
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark-Parque de Ciência e Tecnologia, Barco, 4805-017, Guimarães, Portugal.
- ICVS/3B's, Associate PT Government Laboratory, Braga/Guimarães, Portugal.
| | - Maria C Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites/i3N, University of Minho, 4800-058, Guimarães, Portugal.
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10
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Affiliation(s)
- Magda Silva
- 3B's Research Group, Biomaterials, Biodegradables, and Biomimetics; University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; AvePark-Parque de Ciência e Tecnologia, 4805-017 Barco Guimarães Portugal
- ICVS/3B's, Associate PT Government Laboratory; Braga/Guimarães Portugal
- Institute for Polymers and Composites/I3N, Department of Polymer Engineering; University of Minho; 4800-058 Guimarães Portugal
| | - Natália M. Alves
- 3B's Research Group, Biomaterials, Biodegradables, and Biomimetics; University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; AvePark-Parque de Ciência e Tecnologia, 4805-017 Barco Guimarães Portugal
- ICVS/3B's, Associate PT Government Laboratory; Braga/Guimarães Portugal
| | - Maria C. Paiva
- Institute for Polymers and Composites/I3N, Department of Polymer Engineering; University of Minho; 4800-058 Guimarães Portugal
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11
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Silva M, Caridade SG, Vale AC, Cunha E, Sousa MP, Mano JF, Paiva MC, Alves NM. Biomedical films of graphene nanoribbons and nanoflakes with natural polymers. RSC Adv 2017. [DOI: 10.1039/c7ra04173j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Novel nanostructured free-standing films based on chitosan, alginate and functionalized flake and ribbon-shaped graphene were developed using the layer-by-layer process.
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Affiliation(s)
- Magda Silva
- 3B's Research Group
- Biomaterials, Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- Guimarães
| | - Sofia G. Caridade
- 3B's Research Group
- Biomaterials, Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- Guimarães
| | - Ana C. Vale
- ICVS/3B's
- Associate PT Government Laboratory
- Braga/Guimarães
- Portugal
- Institute for Polymers and Composites/I3N
| | - Eunice Cunha
- Institute for Polymers and Composites/I3N
- Department of Polymer Engineering
- University of Minho
- 4800-058 Guimarães
- Portugal
| | - Maria P. Sousa
- 3B's Research Group
- Biomaterials, Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- Guimarães
| | - João F. Mano
- 3B's Research Group
- Biomaterials, Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- Guimarães
| | - Maria C. Paiva
- Institute for Polymers and Composites/I3N
- Department of Polymer Engineering
- University of Minho
- 4800-058 Guimarães
- Portugal
| | - Natália M. Alves
- 3B's Research Group
- Biomaterials, Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- Guimarães
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12
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Delgado-Lima A, Paiva MC, Machado AV. The influence of melt mixing on the stability of cellulose acetate and its carbon nanotube composites. Journal of Polymer Engineering 2016. [DOI: 10.1515/polyeng-2015-0388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Cellulose derivatives, such as cellulose acetate (CA), are commonly used due to their ease of processing. These polymers present interesting mechanical properties and biodegradability, but low thermal stability under melt processing conditions. Composites of carbon nanotubes (CNTs) and cellulose derivatives are expected to present enhanced properties, depending on the effect of nanotubes on polymer structure and thermal properties. This work aims to investigate the influence of melt mixing on the stability of CA and its CNT composites. Composites with 0 wt%, 0.1 wt% and 0.5 wt% CNTs, as received and functionalized with pyrrolidine groups, were prepared using a batch mixer and an extruder. Chain scission of CA occurred during processing, but the effect was considerably reduced in the presence of CNTs. The incorporation of small amounts of CNTs (with or without functionalization) decreased polymer degradation by thermomechanical effects induced during polymer processing.
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13
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Moura D, Mano JF, Paiva MC, Alves NM. Chitosan nanocomposites based on distinct inorganic fillers for biomedical applications. Sci Technol Adv Mater 2016; 17:626-643. [PMID: 27877909 PMCID: PMC5102025 DOI: 10.1080/14686996.2016.1229104] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/22/2016] [Accepted: 08/22/2016] [Indexed: 05/17/2023]
Abstract
Chitosan (CHI), a biocompatible and biodegradable polysaccharide with the ability to provide a non-protein matrix for tissue growth, is considered to be an ideal material in the biomedical field. However, the lack of good mechanical properties limits its applications. In order to overcome this drawback, CHI has been combined with different polymers and fillers, leading to a variety of chitosan-based nanocomposites. The extensive research on CHI nanocomposites as well as their main biomedical applications are reviewed in this paper. An overview of the different fillers and assembly techniques available to produce CHI nanocomposites is presented. Finally, the properties of such nanocomposites are discussed with particular focus on bone regeneration, drug delivery, wound healing and biosensing applications.
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Affiliation(s)
- Duarte Moura
- 3B’s Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B’s, Associate PT Government Laboratory, Braga, Guimarães, Portugal
- Institute for Polymers and Composites/I3 N, Department of Polymer Engineering, University of Minho, Guimarães, Portugal
| | - João F. Mano
- 3B’s Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B’s, Associate PT Government Laboratory, Braga, Guimarães, Portugal
| | - Maria C. Paiva
- Institute for Polymers and Composites/I3 N, Department of Polymer Engineering, University of Minho, Guimarães, Portugal
| | - Natália M. Alves
- 3B’s Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B’s, Associate PT Government Laboratory, Braga, Guimarães, Portugal
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14
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Santos RM, Vilaverde C, Cunha E, Paiva MC, Covas JA. Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates. Soft Matter 2016; 12:77-86. [PMID: 26439171 DOI: 10.1039/c5sm01366f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene-graft-maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity.
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Affiliation(s)
- R M Santos
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - C Vilaverde
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - E Cunha
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - M C Paiva
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - J A Covas
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
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15
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16
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Gusmão R, Melle-Franco M, Geraldo D, Bento F, Paiva MC, Proença F. Probing the surface of oxidized carbon nanotubes by selective interaction with target molecules. Electrochem commun 2015. [DOI: 10.1016/j.elecom.2015.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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17
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Cunha E, Proença MF, Costa F, Fernandes AJ, Ferro MAC, Lopes PE, González-Debs M, Melle-Franco M, Deepak FL, Paiva MC. Self-assembled functionalized graphene nanoribbons from carbon nanotubes. ChemistryOpen 2015; 4:115-9. [PMID: 25969808 PMCID: PMC4420582 DOI: 10.1002/open.201402135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Indexed: 11/06/2022] Open
Abstract
Graphene nanoribbons (GNR) were generated in ethanol solution by unzipping pyrrolidine-functionalized carbon nanotubes under mild conditions. Evaporation of the solvent resulted in regular few-layer stacks of graphene nanoribbons observed by transmission electron microscopy (TEM) and X-ray diffraction. The experimental interlayer distance (0.49–0.56 nm) was confirmed by computer modelling (0.51 nm). Computer modelling showed that the large interlayer spacing (compared with graphite) is due to the presence of the functional groups and depends on their concentration. Stacked nanoribbons were observed to redissolve upon solvent addition. This preparation method could allow the fine-tuning of the interlayer distances by controlling the number and/or the nature of the chemical groups in between the graphene layers.
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Affiliation(s)
- Eunice Cunha
- Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurem 4800-058, Guimarães, Portugal
| | - Maria Fernanda Proença
- Department of Chemistry, University of Minho, Campus of Gualtar 4710-057, Braga, Portugal
| | - Florinda Costa
- Physics of Semiconductors, Optoelectronics & Disordered Systems/I3N, University of Aveiro 3810-193, Aveiro, Portugal
| | - António J Fernandes
- Physics of Semiconductors, Optoelectronics & Disordered Systems/I3N, University of Aveiro 3810-193, Aveiro, Portugal
| | - Marta A C Ferro
- CICECO, Department of Ceramics & Glass Engineering, University of Aveiro 3810-193, Aveiro, Portugal
| | - Paulo E Lopes
- PIEP-Pole for Innovation in Polymer Engineering, University of Minho, Campus of Azurém 4800-058, Guimarães, Portugal
| | - Mariam González-Debs
- International Iberian Nanotechnology Laboratory (INL Av. Mestre José Veiga, 4715-330, Braga, (Portugal)
| | - Manuel Melle-Franco
- Computer Science & Technology Center, University of Minho Campus of Gualtar, 4710-057, Braga, Portugal
| | - Francis Leonard Deepak
- International Iberian Nanotechnology Laboratory (INL Av. Mestre José Veiga, 4715-330, Braga, (Portugal)
| | - Maria C Paiva
- Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurem 4800-058, Guimarães, Portugal
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18
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Mata D, Amaral M, Fernandes AJS, Colaço B, Gama A, Paiva MC, Gomes PS, Silva RF, Fernandes MH. Diels-Alder functionalized carbon nanotubes for bone tissue engineering: in vitro/in vivo biocompatibility and biodegradability. Nanoscale 2015; 7:9238-9251. [PMID: 25928241 DOI: 10.1039/c5nr01829c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The risk-benefit balance for carbon nanotubes (CNTs) dictates their clinical fate. To take a step forward at this crossroad it is compulsory to modulate the CNT in vivo biocompatibility and biodegradability via e.g. chemical functionalization. CNT membranes were functionalised combining a Diels-Alder cycloaddition reaction to generate cyclohexene (-C6H10) followed by a mild oxidisation to yield carboxylic acid groups (-COOH). In vitro proliferation and osteogenic differentiation of human osteoblastic cells were maximized on functionalized CNT membranes (p,f-CNTs). The in vivo subcutaneously implanted materials showed a higher biological reactivity, thus inducing a slighter intense inflammatory response compared to non-functionalized CNT membranes (p-CNTs), but still showing a reduced cytotoxicity profile. Moreover, the in vivo biodegradation of CNTs was superior for p,f-CNT membranes, likely mediated by the oxidation-induced myeloperoxidase (MPO) in neutrophil and macrophage inflammatory milieus. This proves the biodegradability faculty of functionalized CNTs, which potentially avoids long-term tissue accumulation and triggering of acute toxicity. On the whole, the proposed Diels-Alder functionalization accounts for the improved CNT biological response in terms of the biocompatibility and biodegradability profiles. Therefore, CNTs can be considered for use in bone tissue engineering without notable toxicological threats.
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Affiliation(s)
- D Mata
- CICECO, Materials and Ceramic Eng. Dept., Univ. of Aveiro, 3810-193 Aveiro, Portugal.
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19
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Novais RM, Simon F, Pötschke P, Villmow T, Covas JA, Paiva MC. Poly(lactic acid) composites with poly(lactic acid)-modified carbon nanotubes. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pola.26778] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Rui M. Novais
- Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém; 4800-058 Guimarães Portugal
| | - Frank Simon
- Institute of Physical Chemistry and Polymer Physics; Leibniz Institute of Polymer Research Dresden; Hohe Str. 6 D-01069 Dresden Germany
| | - Petra Pötschke
- Institute of Macromolecular Chemistry; Leibniz Institute of Polymer Research Dresden; Hohe Str. 6 D-01069 Dresden Germany
| | - Tobias Villmow
- Institute of Macromolecular Chemistry; Leibniz Institute of Polymer Research Dresden; Hohe Str. 6 D-01069 Dresden Germany
| | - José A. Covas
- Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém; 4800-058 Guimarães Portugal
| | - Maria C. Paiva
- Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém; 4800-058 Guimarães Portugal
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20
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Rodrigues MM, Fernandes PÁ, Haddad JP, Paiva MC, Souza MDCM, Andrade TCA, Fernandes AP. Frequency of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Mycoplasma hominis and Ureaplasma species in cervical samples. J OBSTET GYNAECOL 2011; 31:237-41. [PMID: 21417648 DOI: 10.3109/01443615.2010.548880] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We investigated the relative frequencies of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Mycoplasma hominis and Ureaplasma sp. in cervical samples. PCR analyses were performed in ectocervical and endocervical samples from 224 patients attending public health services in Belo Horizonte and Contagem, Minas Gerais Brazil. A high prevalence of colonisation of the cervix (6.3% for C. trachomatis, 4.0% for N. gonorrhoeae, 0.9% for M. genitalium, 21.9% for M. hominis, 38.4% for Ureaplasma sp.) was demonstrated not only for pathogens classically associated to cervicitis (C. trachomatis and N. gonorrhoeae), but also for M. hominis and Ureaplasma sp. These findings may be useful to guide more adequate diagnosis to interrupt transmission and to avoid negative impacts on the female reproductive tract.
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Affiliation(s)
- M M Rodrigues
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmacia, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte, Minas Gerais, CEP 31270-901, Brazil
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21
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Araújo R, Fernandes FM, Proença MF, Silva CJR, Paiva MC. The 1,3-dipolar cycloaddition reaction in the functionalization of carbon nanofibers. J Nanosci Nanotechnol 2007; 7:3441-3445. [PMID: 18330154 DOI: 10.1166/jnn.2007.815] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Carbon nanofibers were functionalized using a reaction scheme described in the literature for 1,3-dipolar cycloaddition of azomethine ylides generated in situ by the condensation of an alpha-amino acid and an aldehyde. The reagents used were Z-Gly-OH and paraformaldehyde. Their reaction with carbon nanofibers was studied as a solid mixture by controlled heating in the DSC. An oxazolidinone intermediate was formed as the major product. Z-Gly-OH and paraformaldehyde were also reacted with a model compound (anthracene) in DMF solution leading to the formation of a considerable amount of anthraquinone. These studies suggested that, under the conditions investigated, the 1,3-dipolar cycloaddition reaction was not favoured, and the main result of functionalization was the formation of quinone-type groups as a consequence of an oxidation process.
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Affiliation(s)
- R Araújo
- Departamento de Engenharia de Polímeros, Instituto de Polímeros e Compósitos, Universidade do Minho, 4800-058 Guimarães, Portugal
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22
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Fernandes FM, Araújo R, Proença MF, Silva CJR, Paiva MC. Functionalization of carbon nanofibers by a Diels-Alder addition reaction. J Nanosci Nanotechnol 2007; 7:3514-3518. [PMID: 18330166 DOI: 10.1166/jnn.2007.818] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This paper reports functionalization of CNF via a Diels-Alder addition reaction and the characterization of the obtained materials. The functionalization was assessed by a calorimetric technique (DSC) and the morphology of CNF modified materials was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The functionalization was observed to be dependent on the preparative conditions. Detailed analysis of the CNF modified material surface using TEM, shows a deposited layer homogeneously distributed over the CNF structures with an average thickness of about 15 nm. Finally the chemical activity of the raw CNF and functionalized CNF was analyzed to determine the pH of the point of zero charge (pHpzc) values. The results obtained showed that the functionalized CNF materials presented enhanced acid activity comparatively with the modified carbonaceous materials reported in literature.
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Affiliation(s)
- F M Fernandes
- Departamento de Química, Universidade do Minho, 4710-057 Braga, Portugal
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23
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Abstract
AbstractUnidirectional composite material samples with ultrahigh modulus carbon fibres, treated and untreated by oxygen plasma, and a polycarbonate matrix were prepared and tested. Dynamic mechanical analysis (DMA) was used to study interfacial fibre/matrix interaction and the fragmentation test method was applied to determine interfacial shear strength. For the composite samples with treated carbon fibres, analyzed by DMA, a consistent shift of the loss modulus peak toward higher temperature was observed. The damping ratio was highly affected by residual stresses along the carbon fibre direction due to the large difference of thermal expansion coefficients of matrix and fibres. Critical fibre length and interfacial shear strength, obtained from the fragmentation test, showed substantial improvement for treated fibres as compared to the untreated ones. Plasma oxidation of the fibre surface improved considerably the fibre-matrix interaction. Care must be taken interpreting the DMA results, due to specific characteristics of the system studied.
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Affiliation(s)
- Maria C. Paiva
- 1Department of Polymer Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal
- 2IPC – Institute for Polymers and Composites, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal
| | - João F. Mano
- 1Department of Polymer Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal
- 33B’s Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
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24
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Tafuri WL, Melo MN, Paiva MC, Mosser DM, Tafuri WL. Kinetics of an experimental inflammatory reaction induced by Leishmania major during the implantation of paraffin tablets in mice. Virchows Arch 2000; 437:429-35. [PMID: 11097369 DOI: 10.1007/s004280000231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In leishmaniasis, macrophages play important but potentially divergent roles. They act as the host cell in which the parasite may reside and replicate, and, at the same time, they act as an effector cell with the potential to eliminate the parasite. In this work, we experimentally induced an inflammatory model that provokes a continued recruitment of the monocytes to the site of inflammation. This model was carried out by means of implanting paraffin tablets under the skin of Balb/c or C57BL/6 mice. Mice were then infected with Leishmania major to determine how the monocyte inflammatory response to paraffin could influence the course of infection with L. major. Mice were sacrificed 15, 21, 30, and 45 days after infection, and skin and inflammatory capsule were collected for histopathology. At 15 days and 21 days, the lesions induced by L. major in combination with paraffin contained markedly increased numbers of parasites relative to lesions in parallel control animals infected with L. major (without paraffin). Both Balb/c and C57BL/6 mice exhibited high parasite numbers in their lesions. The intense parasite burden observed following paraffin implantation would suggest that the monocytes-macrophages that are recruited to the lesion are acting more as a host cell permitting parasite growth than as an effector cell capable of eliminating L. major. At later times, the two strains of mice stratified according to their genetic susceptibility/resistance profiles. Susceptible Balb/c mice continue to have large parasite burdens, whereas the resistant C56BL/6 mice begin to control parasite numbers. This later observation indicates that the genetic difference between susceptible and resistant strains is not due to differences in monocyte recruitment and cannot be reversed through the altering of monocyte inflammation.
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Affiliation(s)
- W L Tafuri
- Departamento de Patologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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