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Coimbra P, Gil MH, Sousa HD, Duarte CM. {T O T S I U Rib N Tio T O T S I N}.. 2008:102-7. Abstract
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Silva JM, Duarte AR, Caridade SG, Picart C, Reis RL, Mano JF. {Tailored freestanding multilayered membranes based on chitosan and alginate}. Biomacromolecules. 2014;15. Abstract

© 2014 American Chemical Society. Engineering metabolically demanding tissues requires the supply of nutrients, oxygen, and removal of metabolic byproducts, as well as adequate mechanical properties. In this work, we propose the development of chitosan (CHIT)/alginate (ALG) freestanding membranes fabricated by layer-by-layer (LbL) assembly. CHIT/ALG membranes were cross-linked with genipin at a concentration of 1 mg·mL {\textless} sup {\textgreater} -1 {\textless} /sup {\textgreater} or 5 mg·mL {\textless} sup {\textgreater} -1 {\textless} /sup {\textgreater} . Mass transport properties of glucose and oxygen were evaluated on the freestanding membranes. The diffusion of glucose and oxygen decreases with increasing cross-linking concentration. Mechanical properties were also evaluated in physiological-simulated conditions. Increasing cross-linking density leads to an increase of storage modulus, Young modulus, and ultimate tensile strength, but to a decrease in the maximum hydrostatic pressure. The in vitro biological performance demonstrates that cross-linked films are more favorable for cell adhesion. This work demonstrates the versatility and feasibility of LbL assembly to generate nanostructured constructs with tunable permeability, mechanical, and biological properties.

Duarte AR, Mano JF, Reis RL. {The role of organic solvent on the preparation of chitosan scaffolds by supercritical assisted phase inversion}. Journal of Supercritical Fluids. 2012;72:326-32. Abstract

The aim of this study was to evaluate the possibility of preparing chitosan porous matrixes using supercritical fluid technology. Supercritical immersion precipitation technique was used to prepare scaffolds of a natural biocompatible polymer, chitosan for tissue engineering purposes. The physicochemical and biological properties of chitosan make it an excellent material for the preparation of drug delivery systems and for the development of new biomedical applications in many fields from skin to bone or cartilage. Supercritical assisted phase inversion experiments were carried out and the effect of different organic solvents on the morphology of the scaffolds was assessed. Chitosan scaffold morphology, porosity and pore size were evaluated by SEM and micro-CT. A thermodynamic analysis of the process was carried out and insights on the solubility parameter and Flory-Huggins interaction parameters are given. The preparation of a highly porous and interconnected structure of a natural material, chitosan, using a clean and environmentally friendly technology constitutes a new processing technology for the preparation of scaffolds for tissue engineering using these materials. © 2011 Elsevier B.V.

Duarte AR, Mano JF, Reis RL. {Thermosensitive polymeric matrices for three-dimensional cell culture strategies}. Acta Biomaterialia. 2011;7. Abstract

A completely new strategy for cell culture focusing on the design of three-dimensional (3D) smart surfaces by supercritical fluid technology has been developed. This approach might overcome the limitations on cell expansion and proliferation of currently existing techniques. An alternative technology, based on supercritical carbon dioxide, was used to polymerize poly(N- isopropylacrylamide) (PNIPAAm) and to foam poly(d,l-lactic acid) (P D,L LA), creating a thermosensitive 3D structure which has proven to have potential as a substrate for cell growth and expansion. We demonstrated that the thermosensitive matrices promoted cell detachment, thus P D,L LA scaffolds have the potential to be used as substrates for cell growth and expansion avoiding enzymatic and mechanical methods of cell harvesting. The harvested cells were replated to evaluate their viability, which was not compromised. A major advantage of this technology is the fact that the prepared materials can be recovered and reused. Therefore, the same substrate can be recycled and reused for different batches. An indirect impact of the technology developed is related to the field of biotechnology, as this novel technology for cell expansion can be applied to any adherent cell cultures. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Tutak W, Farooque T, Simon GC. {Tissue Engineering and Regenerative Medicine}. Journal of Tissue Engineering and Regenerative Medicine. 2012;6:1-429. Abstractpdf
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Turner NJ, Sicari BM, Keane TJ, Londono R, Crapo PM, Tottey S, Matsushima R, Shimatsu Y, Nam K, Kimura T, Fujisato T. {Tissue Engineering and Regenerative Medicine}. Journal of Tissue Engineering and Regenerative Medicine. 2012;6:1-429. Abstractpdf
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Duarte AR, Santo VE, Alves A, Silva SS, Moreira-Silva J, Silva TH, Marques AP, Sousa RA, Gomes ME, Mano JF, Reis RL. {Unleashing the potential of supercritical fluids for polymer processing in tissue engineering and regenerative medicine}. Journal of Supercritical Fluids. 2013;79:177-85. Abstractpdf

One of the major scientific challenges that tissue engineering and regenerative medicine (TERM) faces to move from benchtop to bedside regards biomaterials development, despite the latest advances in polymer processing technologies. A variety of scaffolds processing techniques have been developed and include solvent casting and particles leaching, compression molding and particle leaching, thermally induced phase separation, rapid prototyping, among others. Supercritical fluids appear as an interesting alternative to the conventional methods for processing biopolymers as they do not require the use of large amounts of organic solvents and the processes can be conducted at mild temperatures. However, this processing technique has only recently started to receive more attention from researchers. Different processing methods based on the use of supercritical carbon dioxide have been proposed for the creation of novel architectures based on natural and synthetic polymers and these will be unleashed in this paper. © 2013 Elsevier B.V. All rights reserved.

Duarte AR, Santo VE, Alves A, Silva SS, Moreira-Silva J, Silva TH, Marques AP, Sousa RA, Gomes ME, Mano JF, Reis RL. {Unleashing the potential of supercritical fluids for polymer processing in tissue engineering and regenerative medicine}. Journal of Supercritical Fluids. 2013;79:177-85. Abstractpdf

One of the major scientific challenges that tissue engineering and regenerative medicine (TERM) faces to move from benchtop to bedside regards biomaterials development, despite the latest advances in polymer processing technologies. A variety of scaffolds processing techniques have been developed and include solvent casting and particles leaching, compression molding and particle leaching, thermally induced phase separation, rapid prototyping, among others. Supercritical fluids appear as an interesting alternative to the conventional methods for processing biopolymers as they do not require the use of large amounts of organic solvents and the processes can be conducted at mild temperatures. However, this processing technique has only recently started to receive more attention from researchers. Different processing methods based on the use of supercritical carbon dioxide have been proposed for the creation of novel architectures based on natural and synthetic polymers and these will be unleashed in this paper. © 2013 Elsevier B.V. All rights reserved.

Barros AA, Aroso IM, Silva TH, Mano JF, Duarte AR, Reis RL. {Water and carbon dioxide: Green solvents for the extraction of collagen/gelatin from marine sponges}. ACS Sustainable Chemistry and Engineering. 2015;3:254-60. Abstract

Marine sponges are extremely rich in natural products and are considered a promising biological resource. The major objective of this work is to couple a green extraction process with a natural origin raw material to obtain sponge origin collagen/gelatin for biomedical applications. Marine sponge collagen has unique physicochemical properties, but its application is hindered by the lack of availability due to inefficient extraction methodologies. Traditional extraction methods are time consuming as they involve several operating steps and large amounts of solvents. In this work, we propose a new extraction methodology under mild operating conditions in which water is acidified with carbon dioxide (CO2) to promote the extraction of collagen/gelatin from different marine sponge species. An extraction yield of approximately 50{%} of collagen/gelatin was achieved. The results of Fourier transformed infrared spectroscopy (FTIR), circular dichroism (CD), and differential scanning calorimetry (DSC) spectra suggest a mixture of collagen/gelatin with high purity, and the analysis of the amino acid composition has shown similarities with collagen from other marine sources. Additionally, in vitro cytotoxicity studies did not demonstrate any toxicity effects for three of the extracts.

Duarte AR, Shariati A, Rovetto LJ, Peters CJ. {Water cavities of sH clathrate hydrate stabilized by molecular hydrogen: Phase equilibrium measurements}. Journal of Physical Chemistry B. 2008;112. Abstract

In this experimental phase equilibrium study, we show for the first time that it is possible to stabilize structure sH of hydrogen clathrate hydrate with the help of some selected promoters. It was established that the formation pressures of these systems are significantly higher than that of structure sII of hydrogen clathrate hydrate when tetrahydrofuran (THF) is used as a promoter. Although no experimental evidence is available yet, it is estimated that the hydrogen storage capacity of structure sH can be as high as 1.4 wt {%} of H 2 , which is about 40{%} higher compared to the hydrogen storage capacity in structure sH. © 2008 American Chemical Society.