@article {17121, title = {Cellulose acetate fibres loaded with daptomycin for metal implant coatings}, journal = {Carbohydrate polymers}, year = {2021}, pages = {118733}, abstract = {

Multifunctional polymeric coatings containing drug delivery vehicles can play a key role in preventing/reducing biofilm formation on implant surfaces. Their requirements are biocompatibility, good adhesion, and controllable drug release. Although cellulose acetate (CA) films and membranes are widely studied for scaffolding, their applications as a protective coating and drug delivery vehicle for metal implants are scarce. The reason is that adhesion to stainless steel (SS) substrates is non-trivial. Grinding SS substrates enhances the adhesion of dip-coated CA films while the adhesion of electrospun CA membranes is improved by an electrosprayed chitosan intermediate layer. PMMA microcapsules containing daptomycin have been successfully incorporated into CA films and fibres. The released drug concentration of 3 x10-3 mg/mL after 120 minutes was confirmed from the peak luminescence intensity under UV radiation of simulated body fluid (SBF) after immersion of the fibres.

}, url = {https://doi.org/10.1016/j.carbpol.2021.118733}, author = {Faria, Jaime and Bruno Dion{\'\i}sio and Iris Soares and Baptista, Ana Catarina and Ana Cl{\'a}udia Marques and L{\'\i}dia Gon{\c c}alves and Ana Bettencourt and Carlos Baleiz{\~a}o and Ferreira, Isabel} } @article {17122, title = {Electronic control of drug release from gauze or cellulose acetate fibres for dermal applications}, journal = {Journal of Materials Chemistry B}, volume = {9}, year = {2021}, pages = {3515-3522}, abstract = {

Electronic controlled drug release from fibres was studied using ibuprofen as a model drug, one of the most popular analgesics, to impregnate gauze and cellulose acetate (CA) membranes. Conductivity in the range of 1{\textendash}10 mS cm-1 was obtained in polypyrrole (Ppy) functionalised gauze and CA fibres, providing voltage-controlled drug release in a system consisting of Ppy/Ibuprofen/Ppy membranes and an Ag electrode. SEM images evidenced the Ppy adhesion to fibres and Micro Raman spectra proved drug incorporation and release. A small wound adhesive built with these membranes retains ibuprofen at 1.5 V and quickly releases it when -0.5 V is applied.

}, url = {https://pubs.rsc.org/en/content/articlelanding/2021/TB/D1TB00249J}, author = {Baptista, Ana Catarina and Brito, Miguel and Marques, Ana and Ferreira, Isabel} } @article {17125, title = {Carbon threads sweat-based supercapacitors for electronic textiles}, journal = {Scientific Reports}, volume = {10}, year = {2020}, pages = {7703}, abstract = {

Flexible and stretchable energy-storage batteries and supercapacitors suitable for wearable electronics are at the forefront of the emerging field of intelligent textiles. In this context, the work here presented reports on the development of a symmetrical wire-based supercapacitor able to use the wearer{\textquoteright}s sweat as the electrolyte. The inner and outer electrodes consists of a carbon-based thread functionalized with a conductive polymer (polypyrrole) which improves the electrochemical performances of the supercapacitor. The inner electrode is coated with electrospun cellulose acetate fibres, as the separator, and the outer electrode is twisted around it. The electrochemical performances of carbon-based supercapacitors were analyzed using a simulated sweat solution and displayed a specific capacitance of 2.3 F.g-1, an energy of 386.5 mWh.kg-1 and a power density of 46.4 kW.kg-1. Moreover, cycle stability and bendability studies were performed. Such energy conversion device has exhibited a stable electrochemical performance under mechanical deformation, over than 1000 cycles, which make it attractive for wearable electronics. Finally, four devices were tested by combining two supercapacitors in series with two in parallel demonstrating the ability to power a LED.

}, url = {https://www.nature.com/articles/s41598-020-64649-2}, author = {Nuno Lima and Baptista, Ana Catarina and Bruno M. Morais Faustino and Sofia Taborda and Marques, Ana and Ferreira, Isabel} } @article {17112, title = {Conductive Electrospun Polyaniline/Polyvinylpyrrolidone Nanofibers: Electrical and Morphological Characterization of New Yarns for Electronic Textiles}, journal = {Fibers}, volume = {8}, year = {2020}, pages = {24}, abstract = {

Advanced functionalities textiles embedding electronic fibers, yarns and fabrics are a demand for innovative smart cloths. Conductive electrospun membranes and yarns based on polyaniline/polyvinylpyrrolidone (PANI/PVP) were investigated using the chemical modification of PANI instead of using conventional coating processes as in-situ polymerization. PANI was synthesized from the aniline monomer and the influence of the oxidant-to-monomer ratio on electrical conductivity was studied. The optimized conductivity of pellets made with pressed PANI powders was 21 S{\textperiodcentered}cm-1. Yarns were then prepared from the t-Boc-PANI/PVP electrospun membranes followed by PANI protonation to enhance their electrical properties. Using this methodology, electrospun membranes and yarns were produced with electrical conductivities of 1.7 {\texttimes} 10-2 and 4.1 {\texttimes} 10-4 S{\textperiodcentered}cm-1.

}, url = {https://doi.org/10.3390/fib8040024}, author = {Patr{\'\i}cia Perdig{\~a}o and Bruno Faustino and Faria, Jaime and Canejo, Jo{\~a}o Paulo and Borges, Jo{\~a}o Borges and Ferreira, Isabel and Baptista, Ana Catarina} } @proceedings {17124, title = {Demo of PolySense: How to Make Electrically Functional Textiles}, journal = {CHI Conference on Human Factors in Computing Systems}, year = {2020}, pages = {1-4}, abstract = {

We demonstrate a simple and accessible method for enhancing textiles with custom piezo-resistive properties. Based on in-situ polymerization, our method offers seamless integration at the material level, preserving a textile{\textquoteright}s haptic and mechanical properties. We demonstrate how to enhance a wide set of fabrics and yarns using only readily available tools. During each demo session, conference attendees may bring textile samples which will be polymerized in a shared batch. Attendees may keep these samples. While the polymerization is happening, attendees can inspect pre-made samples and explore how these might be integrated in functional circuits. Examples objects created using polymerization include rapid manufacturing of on-body interfaces, tie-dyed motion-capture clothing, and zippers that act as potentiometers.

}, url = {https://doi.org/10.1145/3334480.3383148}, author = {P. Strohmeier and C. Honnet and H. Perner-Wilson and M. Teyssier and B. Fruchard and Baptista, Ana Catarina and J. Steimle} } @article {17127, title = {Customized tracheal design using 3D printing of a polymer hydrogel: influence of UV laser cross-linking on mechanical properties}, journal = {3D Printing in Medicine}, volume = {5}, year = {2019}, pages = {12}, abstract = {

Background
The use of 3D printing of hydrogels as a cell support in bio-printing of cartilage, organs and tissue has attracted much research interest. For cartilage applications, hydrogels as soft materials must show some degree of rigidity, which can be achieved by photo- or chemical polymerization. In this work, we combined chemical and UV laser polymeric cross-linkage to control the mechanical properties of 3D printed hydrogel blends. Since there are few studies on UV laser cross-linking combined with 3D printing of hydrogels, the work here reported offered many challenges.

Methods
Polyethylene glycol diacrylate (PEGDA), sodium alginate (SA) and calcium sulphate (CaSO4) polymer paste containing riboflavin (vitamin B2) and triethanolamine (TEOHA) as a biocompatible photoinitiator was printed in an extrusion 3D plotter using a coupled UV laser. The influence of the laser power on the mechanical properties of the printed samples was then examined in unconfined compression stress-strain tests of 1 {\texttimes} 1 {\texttimes} 1 cm3 sized samples. To evaluate the adhesion of the material between printed layers, compression measurements were performed along the parallel and perpendicular directions to the printing lines.

Results
At a laser density of 70 mW/cm2, Young{\textquoteright}s modulus was approximately 6 MPa up to a maximum compression of 20\% in the elastic regime for both the parallel and perpendicular measurements. These values were within the range of biological cartilage values. Cytotoxicity tests performed with Vero cells confirmed the cytocompatibility.

Conclusions
We printed a partial tracheal model using optimized printing conditions and proved that the materials and methods developed may be useful for printing of organ models to support surgery or even to produce customized tracheal implants, after further optimization.

}, url = {https://threedmedprint.biomedcentral.com/articles/10.1186/s41205-019-0049-8}, author = {Ana Filipa Cristov{\~a}o and David Sousa and Filipe Silvestre and Ropio, In{\^e}s and Ana Gaspar and C{\'e}lia Henriques and Velhinho, Alexandre and Baptista, Ana Catarina and Miguel Faustino and Ferreira, Isabel} } @article {17126, title = {Synthesis of thermoelectric magnesium-silicide pastes for 3D printing, electrospinning and low-pressure spray}, journal = {Materials for Renewable and Sustainable Energy}, volume = {8}, year = {2019}, pages = {21}, abstract = {

In this work, eco-friendly magnesium-silicide (Mg2Si) semiconducting (n-type) thermoelectric pastes for building components concerning energy-harvesting devices through 3D printing, spray and electrospinning were synthetized and tested for the first time. The Mg2Si fine powders were obtained through the combination of ball milling and thermal annealing under Ar atmosphere. While the latter process was crucial for obtaining the desired Mg2Si phase, the ball milling was indispensable for homogenizing and reducing the grain size of the powders. The synthetized Mg2Si powders exhibited a large Seebeck coefficient of ~ 487 {\textmu}V/K and were blended with a polymeric solution in different mass ratios to adjust the paste viscosity to the different requirements of 3D printing, electrospinning and low-pressure spray. The materials produced in every single stage of the paste synthesis were characterized by a variety of techniques that unequivocally prove their viability for producing thermoelectric parts and components. These can certainly trigger further research and development in green thermoelectric generators (TEGs) capable of adopting any form or shape with enhanced thermoelectric properties. These green TEGs are meant to compete with common toxic materials such as Bi2Te3, PbTe and CoSb that have Seebeck coefficients in the range of ~ 290{\textendash}700 μV/K, similar to that of the produced Mg2Si powders and lower than that of 3D printed bulk Mg2Si pieces, measured to be ~ 4866 μV/K. Also, their measured thermal conductivities proved to be significantly lower (~ 0.2 W/mK) than that reported for Mg2Si (>= 4 W/mK). However, it is herein demonstrated that such thermoelectric properties are not stable over time. Pressureless sintering proved to be indispensable, but difficultly achievable by long thermal annealing (even above 32 h) in inert atmosphere at 400 {\textdegree}C, at least for bulk Mg2Si pieces constituted by a mean grain size of 2{\textendash}3 μm. Hence, for overcoming this sintering challenge and become the silicide{\textquoteright}s extrusion viable in the production of bulk thermoelectric parts, alternative pressureless sintering methods will have to be further explored.

}, url = {https://link.springer.com/article/10.1007\%2Fs40243-019-0159-7}, author = {Marques, Ana and Miglietta, Davide and G. Gaspar and Baptista, Ana Catarina and Gaspar, A. and Perdig{\~a}o, P. and Iris Soares and Bianchi, Catarina and David Sousa and Bruno M. Morais Faustino and Amaral, V. S. and Santos, T. and Gon{\c c}alves, A. P. and R.C. da Silva and Giorgis, Fabrizio and Ferreira, Isabel} } @article {17109, title = {Using water to control electrospun Polycaprolactone fibre morphology for soft tissue engineering}, journal = {Journal of Polymer Research}, volume = {26}, year = {2019}, pages = {222}, abstract = {

Control of the properties of electrospun polycaprolactone can be achieved by adjusting the acetic acid:water ratio used to dissolve and electrospin the polymer. In this work, we studied the effect of using up to 15 wt\% water in the solvent mixture. Solution conductivity and viscosity and fibre morphology vary dramatically with water content and solution age. Two days after initial solution preparation, electrospinning yields regular fibres for a water content of 0 wt\% and 5 wt\%, irregular fibres for a 10 wt\% water content and irregular and fused fibres for a 15 wt\% water content. Fibres with the highest crystallinity (60\%) were obtained from solutions containing 5 wt\% water while the highest elastic modulus (8.6 {\textpm} 1.4 MPa) and tensile stress (4.3 {\textpm} 0.3 MPa) pertain to fibres obtained from solutions containing 10 wt\% water. Enzymatic fibre degradation is faster the higher the water content in the precursor solution. Adhesion ratio of human foetal fibroblasts was highest on scaffolds obtained from precursor solutions containing 0 wt\% water. Cell population increases for all scaffolds and populations quickly become equivalent, with no statistically significant differences between them. Cells exhibit a more extended morphology on the 5 wt\% scaffold and a more compact morphology on the 0 wt\% scaffold. In summary, a small water content in the solvent allows a significant control over fibre diameter, scaffold properties and the production of scaffolds that support cell adhesion and proliferation. This strategy can be used in soft tissue engineering to influence cell behaviour and the degradation rate of the scaffolds.

}, url = {https://link.springer.com/article/10.1007/s10965-019-1890-6}, author = {Susana Gomes and Diana Querido and Jos{\'e} Lu{\'\i}s Ferreira and Borges, Jo{\~a}o Borges and C{\'e}lia Henriques and Silva, Jorge Carvalho} } @article {17104, title = {Cellulose paper functionalised with polypyrrole and poly(3,4-ethylenedioxythiophene) for paper battery electrodes}, journal = {Organic Electronics}, volume = {62}, year = {2018}, pages = {530-535}, abstract = {

A simple process of commercial paper functionalisation via in situ polymerisation of conductive polymers onto cellulose fibres was investigated and applied as electrodes in paper-based batteries. The functionalisation involved polypyrrole (PPy) and Poly (3,4-ethylenedioxythiophene) (PEDOT) as conductive polymers with the process of functionalisation optimised for each polymer individually with respect to oxidant-to-monomer ratios and polymerisation times and temperature. Paper with conductivity values of 44 mS/cm was obtained by exposing the samples to pyrrole vapour for a period of 30 min at room temperature; however, polymerisation at temperatures of 40 {\textdegree}C lead to higher conductivity values to up 141 mS/cm. Consequently, functionalised PPy and PEDOT papers were applied as cathodes in batteries with Al foil anodes and commercial paper soaked in an electrolyte solution of NaCl.

}, url = {https://doi.org/10.1016/j.orgel.2018.06.025}, author = {Ropio, In{\^e}s and Baptista, Ana Catarina and Nobre, Joana and J. Correia and F. Belo and S. Taborda and B. M. Morais Faustino and Borges, Jo{\~a}o Borges and A. Kovalenko and Ferreira, Isabel} } @article {12918, title = {Cellulose-based electrospun fibers functionalized with polypyrrole and polyaniline for fully organic batteries}, journal = {Journal of Materials Chemistry A}, volume = {6}, year = {2018}, pages = {256-265}, abstract = {

A novel cellulose-based bio-battery made of electrospun fibers activated by biological fluids has been developed. This work reports a new concept for a fully organic bio-battery that takes advantage of the high surface to volume ratio achieved by an electrospun matrix composed of sub-micrometric fibers that acts simultaneously as the separator and the support of the electrodes. Polymer composites of polypyrrole (PPy) and polyaniline (PANI) with cellulose acetate (CA) electrospun matrix were produced by in situ chemical oxidation of pyrrole and aniline on the CA fibers. The structure (CA/PPy|CA|CA/PANI) generated a power density of 1.7 mW g-1 in the presence of simulated biological fluids, which is a new and significant contribution to the domain of medical batteries and fully organic devices for biomedical applications.

}, url = {http://pubs.rsc.org/en/content/articlelanding/2018/ta/c7ta06457h/unauth$\#$!divAbstract}, author = {Baptista, Ana Catarina and Ropio, In{\^e}s and Romba, Beatriz and Nobre, Joana and C{\'e}lia Henriques and Silva, Jorge Carvalho and Martins, J. I. and Borges, Jo{\~a}o Paulo and Ferreira, Isabel} } @article {13909, title = {Functional Stimuli-Responsive Gels: Hydrogels and Microgels}, journal = {Gels}, volume = {4}, year = {2018}, pages = {54}, abstract = {

One strategy that has gained much attention in the last decades is the understanding and further mimicking of structures and behaviours found in nature, as inspiration to develop materials with additional functionalities. This review presents recent advances in stimuli-responsive gels with emphasis on functional hydrogels and microgels. The first part of the review highlights the high impact of stimuli-responsive hydrogels in materials science. From macro to micro scale, the review also collects the most recent studies on the preparation of hybrid polymeric microgels composed of a nanoparticle (able to respond to external stimuli), encapsulated or grown into a stimuli-responsive matrix (microgel). This combination gave rise to interesting multi-responsive functional microgels and paved a new path for the preparation of multi-stimuli {\textquotedblleft}smart{\textquotedblright} systems. Finally, special attention is focused on a new generation of functional stimuli-responsive polymer hydrogels able to self-shape (shape-memory) and/or self-repair. This last functionality could be considered as the closing loop for smart polymeric gels.

}, url = {https://www.mdpi.com/2310-2861/4/2/54}, author = {Coro Echeverria and Fernandes, Susete N. and Godinho, Maria Helena and Borges, Jo{\~a}o Borges and Paula I P Soares} } @article {12922, title = {Fluorescent and conductive cellulose acetate-based membranes with porphyrins}, journal = {Materials today Communications}, volume = {11}, year = {2017}, pages = {26-37}, abstract = {

The unique properties of electrospun nanofibers combined with functional compounds allow the preparation of novelty materials that can be employed in a wide range of applications. Among a vast number of polymers, Cellulose Acetate (CA) it is considered easy to electrospun and it was employed as the polymeric matrix, where free and iridium-porphyrins were incorporated. Two different solvent systems were employed according to the porphyrin used, and the best dispersion level on both the electrospun solution and the membranes, was achieved with the iridium porphyrin. The nanofibers with this porphyrin also exhibited electrical properties, while the fluorescence was quenched by the presence of specific axial ligands.

}, url = {https://www.sciencedirect.com/science/article/pii/S2352492816301234}, author = {Delgado-Lima, Ana and Borges, Jo{\~a}o Paulo and Ferreira, Isabel and Machado, Ana} } @inbook {12923, title = {Hybrid polysaccharide-based systems for biomedical applications}, booktitle = {Hybrid Polymer Composite Materials: Applications}, year = {2017}, pages = {107-149}, publisher = {Woodhead Publishing, Elsevier}, organization = {Woodhead Publishing, Elsevier}, address = {USA}, abstract = {

Hybrid materials have been widely studied for structural applications. Polysaccharide-based fibers, especially cellulosic fibers, have been explored in the last two decades as substitutes of the traditional reinforcements made of glass or carbon fibers due to their mechanical properties. However, their biocompatibility, biodegradability, and chemistry have attracted the researchers and new developments in the field of smart and functional materials arise in diverse applications. This chapter will focus on the biomedical applications of polysaccharide-based smart and functional materials, namely those concerning biosensors and actuators, theranostic systems, and tissue-engineering applications. Special attention will be given to cellulose- and chitin/chitosan-based hybrid materials because these are the two most abundant polysaccharides and probably the most promising for the development of hybrid materials for biomedical applications. Biomimetic strategies for the development of smart and functional hybrid materials will also be highlighted.

}, url = {https://doi.org/10.1016/B978-0-08-100785-3.00004-8}, author = {Paula I P Soares and Coro Echeverria and Baptista, Ana Catarina and Jo{\~a}o, Carlos and Fernandes, Susete and Almeida, Ana and Silva, Jorge Carvalho and Godinho, Maria Helena and Borges, Jo{\~a}o Paulo}, editor = {Manju Kumari Thakur and Thakur, Vijay Kumar and Asokan Pappu} } @article {12919, title = {Towards the development of multifunctional hybrid fibrillary gels: production and optimization by colloidal electrospinning}, journal = {RSC Advances}, volume = {7}, year = {2017}, pages = {48972-48979}, abstract = {

The incorporation of thermosensitive microgels that can act as active sites into polymeric fibers through colloidal electrospinning originates multifunctional, highly porous, and biocompatible membranes suitable for biomedical applications. The use of polyvinylpyrrolidone (PVP), a biocompatible, water-soluble polymer as a fiber template, not only allows the use of a simple set-up to produce composite membranes, but also avoids the use of organic solvents to prepare such systems. Further crosslinking with ultraviolet (UV) radiation avoids membrane dissolution in physiological conditions. Highly porous, UV crosslinked composite membranes with monodisperse mean fiber diameters around 530 nm were successfully produced. These composite membranes showed a Young Modulus of 22 MPa, and an ultimate tensile strength of 3 MPa, accessed in the mechanical tests. Furthermore, the same composite membranes were able to swell about 30 times their weight after 1 hour in aqueous medium. In this work composite multifunctional membranes were designed and extensively studied. PVP, a biocompatible water-soluble polymer, was used as a fiber template to incorporate thermoresponsive poly-(N-isopropylacrylamide) (PNIPAAm)-based microgels into the composite membrane using colloidal electrospinning. The design of multifunctional membranes can be further tailored to several biomedical applications such as temperature-controlled drug delivery systems.

}, url = {http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra07166c$\#$!divAbstract}, author = {Faria, Jaime and Coro Echeverria and Borges, Jo{\~a}o Paulo and Godinho, Maria Helena and Paula I P Soares} } @article {10734, title = {Chitosan-based nanoparticles as drug delivery systems for doxorubicin: optimization and modelling}, journal = {Carbohydrate polymers}, volume = {147}, year = {2016}, pages = {304-312}, abstract = {

In the present work, two drug delivery systems were produced by encapsulating doxorubicin into chitosan and O-HTCC (ammonium-quaternary derivative of chitosan) nanoparticles. The results show that doxorubicin release is independent of the molecular weight and is higher at acidic pH (4.5) than at physiological pH. NPs with an average hydrodynamic diameter bellow 200 nm are able to encapsulate up to 70\% and 50\% of doxorubicin in the case of chitosan and O-HTCC nanoparticles, respectively. O-HTCC nanoparticles led to a higher amount of doxorubicin released than chitosan nanoparticles, for the same experimental conditions, although the release mechanism was not altered. A burst effect occurs within the first hours of release, reaching a plateau after 24 h. Fitting mathematical models to the experimental data led to a concordant release mechanism between most samples, indicating an anomalous or mixed release, which is in agreement with the swelling behavior of chitosan described in the literature.

}, keywords = {Chitosan, Doxorubicin, Drug delivery, Mathematical modelling, O-HTCC}, isbn = {0144-8617}, url = {http://www.sciencedirect.com/science/article/pii/S0144861716302570}, author = {Paula I P Soares and Sousa, Ana Isabel and Silva, Jorge Carvalho and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @article {10815, title = {Iron oxide nanoparticles stabilized with a bilayer of oleic acid for magnetic hyperthermia and MRI applications}, journal = {Applied Surface Science}, volume = {383}, year = {2016}, pages = {240-247}, abstract = {

Iron oxide nanoparticles (Fe3O4, IONPs) are promising candidates for several biomedical applications such as magnetic hyperthermia and as contrast agents for magnetic resonance imaging (MRI). However, their colloidal stability in physiological conditions hinders their application requiring the use of biocompatible surfactant agents. The present investigation focuses on obtaining highly stable IONPs, stabilized by the presence of an oleic acid bilayer. Critical aspects such as oleic acid concentration and pH were optimized to ensure maximum stability. NPs composed of an iron oxide core with an average diameter of 9 nm measured using transmission electron microscopy (TEM) form agglomerates with an hydrodynamic diameter of around 170 nm when dispersed in water in the presence of an oleic acid bilayer, remaining stable (zeta potential of -120 mV). Magnetic hyperthermia and the relaxivities measurements show high efficiency at neutral pH which enables their use for both magnetic hyperthermia and MRI.

}, url = {http://www.sciencedirect.com/science/article/pii/S0169433216309709}, author = {Paula I P Soares and Laia, C{\'e}sar and Alexandra Carvalho and Laura Pereira and Coutinho, Joana and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @inbook {10329, title = {Natural Nanofibres for Composite Applications}, booktitle = {Fibrous and Textile Materials for Composite Applications}, year = {2016}, pages = {261-299}, publisher = {Springer Singapore}, organization = {Springer Singapore}, address = {Singapore}, abstract = {

Cellulose and chitin are the two most abundant natural polysaccharides. Both have a semicrystalline microfibrillar structure from which nanofibres can be extracted. These nanofibres are rod-like microcrystals that can be used as nanoscale reinforcements in composites due to their outstanding mechanical properties. This chapter starts by reviewing the sources, extraction methods and properties of cellulose and chitin nanofibres. Then, their use in the fabrication of structural and functional nanocomposites and the applications that have been investigated are reviewed. Nanocomposites are materials with internal nano-sized structures. They benefit from the properties of the nanofillers: low density, nonabrasive, nontoxic, low cost, susceptibility to chemical modifications and biodegradability. Diverse manufacturing technologies have been used to produce films, fibres, foams, sponges, aerogels, etc. Given their natural origin and high stiffness, these polymers have attracted a lot of attention not only in the biomedical and tissue engineering fields but also in areas such as pharmaceutics, cosmetics, agriculture, biosensors and water treatment.

}, url = {http://link.springer.com/chapter/10.1007/978-981-10-0234-2_8}, author = {Jo{\~a}o, Carlos and Baptista, Ana Catarina and Ferreira, Isabel and Silva, Jorge Carvalho and Borges, Jo{\~a}o Paulo}, editor = {Sohel Rana and Raul Fangueiro} } @article {10816, title = {Thermal and magnetic properties of chitosan-iron oxide nanoparticles}, journal = {Carbohydrate polymers}, volume = {149}, year = {2016}, pages = {382-390}, abstract = {

Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications.
In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan.

}, keywords = {Chitosan, Iron oxide nanoparticles, Magnetic hyperthermia, Magnetite}, isbn = {0144-8617}, url = {http://www.sciencedirect.com/science/article/pii/S0144861716305008}, author = {Paula I P Soares and Diana Machado and Laia, C{\'e}sar and Laura Pereira and Coutinho, Joana and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @article {10994, title = {Towards the development of multifunctional chitosan-based iron oxide nanoparticles: Optimization and modelling of doxorubicin release}, journal = {Carbohydrate Polymers}, volume = {153}, year = {2016}, pages = {212-221}, abstract = {

In the present work composite nanoparticles with a magnetic core and a chitosan-based shell were produced as drug delivery systems for doxorubicin (DOX). The results show that composite nanoparticles with a hydrodynamic diameter within the nanometric range are able to encapsulate more DOX than polymeric nanoparticles alone corresponding also to a higher drug release. Moreover the synthesis method of the iron oxide nanoparticles influences the total amount of DOX released and a high content of iron oxide nanoparticles inhibits DOX release. The modelling of the experimental results revealed a release mechanism dominated by Fickian diffusion.

}, url = {10.1016/j.carbpol.2016.07.109}, author = {Paula I P Soares and Sousa, Ana Isabel and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Borges} } @article {10335, title = {Down conversion photoluminescence on PVP/Ag-nanoparticles electrospun composite fibers}, journal = {Optical Materials}, volume = {39}, year = {2015}, pages = {278{\textendash}281}, abstract = {

The influence of Ag nanoparticles (Ag NPs) on the luminescence of electrospun nonwoven mats made of polyvinylpyrrolidone (PVP) has been studied in this work. The PVP fibers incorporating 2.1{\textendash}4.3 nm size Ag NPs show a significant photoluminescence (PL) band between 580 and 640 nm under 325 nm laser excitation. The down conversion luminescence emission is present even after several hours of laser excitation, which denotes the durability and stability of fibers to consecutive excitations. As so these one-dimensional photonic fibers made using cheap methods is of great importance for organic optoelectronic applications, fluorescent clothing or counterfeiting labels.

}, url = {http://dx.doi.org/10.1016/j.optmat.2014.11.015}, author = {Baptista, Ana Catarina and Botas, Alexandre and Almeida, Ana and Nicolau, Ana and Falc{\~a}o, Bruno and Soares, Manuel and Leit{\~a}o, Joaquim Pratas and Rodrigo Martins and Borges, Jo{\~a}o Paulo and Ferreira, Isabel} } @article {10331, title = {One-pot synthesis of dual-stimuli responsive hybrid PNIPAAm-chitosan microgels}, journal = {Materials \& Design}, volume = {86}, year = {2015}, pages = {745-751}, abstract = {

The incorporation of magnetic nanoparticles into poly(N-isopropylacrylamide) (PNIPAAm) and chitosan microgels gives rise to hybrid systems that combine the microgels swelling capacity with the interesting features presented in magnetic nanoparticles. The presence of chitosan that act as surfactant for magnetic nanoparticles provides a simplistic approach which allows the encapsulation of magnetic nanoparticles without any previous surface modification. Spherical and highly monodisperse microgels with diameters in the range of 200 to 500 nm were obtained. The encapsulation of magnetic nanoparticles in the polymer matrix was confirmed by high resolution Scanning Electron Microscopy in transmission mode. Volume phase transition of the microgels was accessed by Dynamic Light Scattering measurements. It was observed that the thermosensitivity of the PNIPAM microgels still persists in the hybrid microgels; however, the swelling ability is compromised in the microgels with highest chitosan content. The heating performance of the hybrid magnetic microgels, when submitted to an alternating magnetic field, was also evaluated demonstrating the potential of these systems for hyperthermia treatments.

}, url = {http://www.sciencedirect.com/science/article/pii/S0264127515302392}, author = {Coro Echeverria and Paula I P Soares and Ana Robalo and Laura Pereira and Novo, Carlos and Ferreira, Isabel and Borges, Jo{\~a}o Paulo} } @article {10332, title = {Thermal and magnetic properties of iron oxide colloids: influence of surfactants}, journal = {Nanotechnology}, volume = {26}, year = {2015}, pages = {425704}, abstract = {

Iron oxide nanoparticles (NPs) have been extensively studied in the last few decades for several biomedical applications such as magnetic resonance imaging, magnetic drug delivery and hyperthermia. Hyperthermia is a technique used for cancer treatment which consists in inducing a temperature of about 41{\textendash}45 {\textdegree}C in cancerous cells through magnetic NPs and an external magnetic field. Chemical precipitation was used to produce iron oxide NPs 9 nm in size coated with oleic acid and trisodium citrate. The influence of both stabilizers on the heating ability and in vitro cytotoxicity of the produced iron oxide NPs was assessed. Physicochemical characterization of the samples confirmed that the used surfactants do not change the particles{\textquoteright} average size and that the presence of the surfactants has a strong effect on both the magnetic properties and the heating ability. The heating ability of Fe3O4 NPs shows a proportional increase with the increase of iron concentration, although when coated with trisodium citrate or oleic acid the heating ability decreases. Cytotoxicity assays demonstrated that both pristine and trisodium citrate Fe3O4 samples do not reduce cell viability. However, oleic acid Fe3O4 strongly reduces cell viability, more drastically in the SaOs-2 cell line. The produced iron oxide NPs are suitable for cancer hyperthermia treatment and the use of a surfactant brings great advantages concerning the dispersion of NPs, also allowing better control of the hyperthermia temperature.

}, url = {http://iopscience.iop.org/article/10.1088/0957-4484/26/42/425704/meta}, author = {Paula I P Soares and Frederik Lochte and Coro Echeverria and Laura Pereira and Coutinho, Joana and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @inbook {10394, title = {Application of Hyperthermia for Cancer Treatment: Recent Patents Review}, booktitle = {Topics in Anti-Cancer Research, Vol. 3}, year = {2014}, pages = {342-383}, publisher = {Bentham Science Publishers}, organization = {Bentham Science Publishers}, abstract = {

Cancer is one of the main causes of death in the world and its incidence increases every day. Current treatments are insufficient and present many breaches. Hyperthermia is an old concept and was early established as a cancer treatment option, mainly in superficial cancers. More recently, the concept of intracellular hyperthermia emerged wherein magnetic particles are concentrated at the tumor site and remotely heated using an applied magnetic field to achieve hyperthermic temperatures (42-45{\textordmasculine}C). Many patents have been registered in this area since the year 2000. This chapter presents the most relevant information organized in two main categories according to the use or not of nanotechnology. The patents without nanotechnology were divided into the following subcategories: 1) external Radio-Frequency devices; 2) hyperthermic perfusion; 3) frequency enhancers; 4) applying heat to the target site using a catheter; and 5) injection of magnetic and ferroelectric particles. The patents with nanotechnology were divided into three subcategories: 1) hyperthermia devices; 2) nanoparticles; and 3) nanostructures. The use of magnetic nanoparticles is a very promising treatment approach since it may be used for diagnostic and treatment. Magnetic nanoparticle could be applied to detect and diagnose the tumor and to carry a pharmacological active drug to be delivered in the tumor site or apply hyperthermia through an external magnetic field.

}, url = {http://ebooks.benthamscience.com/book/9781608059089/chapter/125650/}, author = {Paula I P Soares and Ferreira, Isabel and Borges, Jo{\~a}o Paulo}, editor = {Atta-ur-Rahman and Khurshid Zaman} } @inbook {10338, title = {Cellulose-Based Liquid Crystalline Composite Systems}, booktitle = {Nanocellulose Polymer Nanocomposites: Fundamentals and Applications}, year = {2014}, pages = {215-235}, publisher = {John Wiley \& Sons, Inc.}, organization = {John Wiley \& Sons, Inc.}, address = {Hoboken, NJ, USA}, url = {http://onlinelibrary.wiley.com/doi/10.1002/9781118872246.ch8/summary}, author = {Borges, Jo{\~a}o Paulo and Canejo, Jo{\~a}o Paulo and Fernandes, Susete and Brogueira, Pedro and Godinho, Maria Helena}, editor = {Thakur, Vijay Kumar} } @article {10339, title = {Effects of surfactants on the magnetic properties of iron oxide colloids}, journal = {Journal of Colloid and Interface Science}, volume = {419}, year = {2014}, pages = {46{\textendash}51}, abstract = {

Iron oxide nanoparticles are having been extensively investigated for several biomedical applications such as hyperthermia and magnetic resonance imaging. However, one of the biggest problems of these nanoparticles is their aggregation.
Taking this into account, in this study the influence of three different surfactants (oleic acid, sodium citrate and Triton X-100) each one with various concentrations in the colloidal solutions stability was analyzed by using a rapid and facile method, the variation in the optical absorbance along time.
The synthesized nanoparticles through chemical precipitation showed an average size of 9 nm and a narrow size distribution. X-ray diffraction pattern and Fourier Transform Infrared analysis confirmed the presence of pure magnetite. SQUID measurements showed superparamagnetic properties with a blocking temperature around 155 K. In addition it was observed that neither sodium citrate nor Triton X-100 influences the magnetic properties of the nanoparticles. On the other hand, oleic acid in a concentration of 64 mM decreases the saturation magnetization from 67 to 45 emu/g. Oleic acid exhibits a good performance as stabilizer of the iron oxide nanoparticles in an aqueous solution for 24 h, for concentrations that lead to the formation of the double layer.

}, url = {http://dx.doi.org/10.1016/j.jcis.2013.12.045}, author = {Paula I P Soares and Alves, Ana and Laura Pereira and Coutinho, Joana and Ferreira, Isabel and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @article {10337, title = {Electrospinning polycaprolactone dissolved in glacial acetic acid: Fiber production, nonwoven characterization, and In Vitro evaluation}, journal = {Journal of Applied Polymer Science}, volume = {131}, year = {2014}, pages = {41068}, abstract = {

The electrospinning of polycaprolactone (PCL) dissolved in glacial acetic acid and the characterization of the resultant nonwoven fiber mats is reported in this work. For comparison purposes, PCL fiber mats were also obtained by electrospinning the polymer dissolved in chloroform. Given the processing parameters chosen, results show that 14 and 17 wt \% PCL solutions are not viscous enough and yield beaded fibers, 20 and 23 wt \% solutions give rise to high quality fibers and 26 wt \% solutions yield mostly irregular and fused fibers. The nonwoven mats are highly porous, retain the high tensile strain of PCL, and the fibers are semicrystalline. Cells adhere and proliferate equally well on all mats, irrespective of the solvent used in their production. In conclusion, mats obtained by electrospinning PCL dissolved in acetic acid are also a good option to consider when producing scaffolds for tissue engineering. Moreover, acetic acid is miscible with polar solvents, which may allow easier blending of PCL with hydrophilic polymers and therefore achieve the production of electrospun nanofibers with improved properties.

}, url = {http://onlinelibrary.wiley.com/doi/10.1002/app.41068/full}, author = {Ferreira, Jos{\'e} Luis and Susana Gomes and C{\'e}lia Henriques and Borges, Jo{\~a}o Paulo and Silva, Jorge Carvalho} } @inbook {7329, title = {Cellulose-based bioelectronic devices}, booktitle = {Cellulose - Medical, Pharmaceutical and Electronic Applications}, number = {4}, year = {2013}, publisher = {InTech}, organization = {InTech}, author = {Baptista, Ana Catarina and Ferreira, Isabel and Borges, Jo{\~a}o}, editor = {Theo van de Ven and Louis Godbout} } @inbook {7330, title = {Cellulose-based composite systems for biomedical applications}, booktitle = {Biomass based Biocomposites}, year = {2013}, pages = {47-60}, publisher = {Smithers Rapra Technology}, organization = {Smithers Rapra Technology}, chapter = {3}, address = {U.K.}, author = {Baptista, Ana Catarina and Ferreira, Isabel and Borges, Jo{\~a}o Paulo}, editor = {Thakur, Vijay Kumar and Singha, A.S.} } @article {7340, title = {Electrospun fibers in composite materials for medical applications}, journal = {Journal of Composites and Biodegradable Polymers }, volume = {1}, year = {2013}, pages = {56-65}, abstract = {

The development of nanoscaled materials has deserved a remarkable interest for biomedical applications. Biological tissues are essentially composite materials with particular mechanical properties that should be carefully considered during the design of innovative biomedical scaffolds. Electrospun membranes are often found in medical applications due to its high specific surface which creates a 3D porous structure that mimics the native extracellular matrix. These electrospun membranes can also be designed to have enhanced mechanical properties, biocompatibility and cellular response making them appealing and inspiring to be used in composites materials.
This paper reviews the new insights in the development of advanced nanostructured composites materials based on electrospun fibers. From tissue engineering to bioelectronics, these composite materials can be found in the most promising research developments for the medical applications.

}, url = {http://www.savvysciencepublisher.com/jms/index.php/jcbp/article/view/100/pdf_6}, author = {Baptista, Ana Catarina and Ferreira, Isabel and Borges, Jo{\~a}o Paulo} } @inbook {7331, title = {Nanofibers and nanoparticles in biomedical applications}, booktitle = {Bioengineered Nanomaterials}, year = {2013}, publisher = {CRC Press (Taylor \& Francis Group)}, organization = {CRC Press (Taylor \& Francis Group)}, chapter = {4}, address = {USA}, url = {https://books.google.pt/books?id=yW3SBQAAQBAJ\&pg=PA65\&lpg=PA65\&dq=Nanofibers+and+nanoparticles+in+biomedical+applications,+Chapter+4\&source=bl\&ots=HmUX3jZ9iP\&sig=2SqCqbb-f0yhM389O_H7m7bd4_s\&hl=pt-PT\&sa=X\&ved=0ahUKEwjQjMDNuM3ZAhXBbhQKHSaACE0Q6AEILTAA$\#$v=one}, author = {Baptista, Ana Catarina and Paula I P Soares and Ferreira, Isabel and Borges, Jo{\~a}o Paulo}, editor = {Tiwari, Atul and Tiwari, Ashutosh} } @article {7333, title = {Strongly Photosensitive and Fluorescent F8T2 Electrospun Fibers}, journal = {Macromol Mater Eng}, volume = {298}, number = {2}, year = {2013}, pages = {174-180}, abstract = {

Electrospun fibers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2) with exceptional electro-optical performance are obtained. The I/T characteristics measured in fibers with 7{\textendash}15 {\textmu}m diameter and 1 mm length show a semiconductor behavior; their thermal activation energy is 0.5 eV and the dark conductivity at RT is 5 {\texttimes} 10-9 (Ω cm)-1. Besides exhibiting a photosensitivity of about 60 under white light illumination with a light power intensity of 25 mW {\textperiodcentered} cm-2, the fibers also attain RT photoluminescence in the cyan, yellow, and red wavelength range under ultraviolet, blue, and green light excitation, respectively. Optical microscope images of F8T2 reveal homogeneous electrospun fibers, which are in good agreement with the uniformly radial fluorescence observed.

}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mame.201200009/abstract?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+27th+February+from+09\%3A00-14\%3A00+GMT+\%2F+04\%3A00-09\%3A00+EST+\%2F+17\%3A00-22\%3A00+SGT+for+essential+maintenance.++Apolog}, author = {Ferreira, Isabel and Baptista, Ana Catarina and Leit{\~a}o, Joaquim Pratas and Soares, Jorge and Elvira Fortunato and Rodrigo Martins and Borges, Jo{\~a}o Paulo} } @article {10395, title = {Application of Hyperthermia for Cancer Treatment: Recent Patents Review}, journal = {Recent Patents on Anti-Cancer Drug Discovery}, volume = {7}, year = {2012}, month = {2012}, pages = {64-73}, abstract = {

Cancer is one of the main causes of death in the world and its incidence increases every day. Current treatments are insufficient and present many breaches. Hyperthermia is an old concept and since early it was established as a cancer treatment option, mainly in superficial cancers. More recently the concept of intracellular hyperthermia emerged wherein magnetic particles are concentrated at the tumor site and remotely heated using an applied magnetic field to achieve hyperthermic temperatures (42-45{\textdegree}C). Many patents have been registered in this area since the year 2000. This review presents the most relevant information, organizing them according to the hyperthermic method used: 1) external Radio- Frequency devices; 2) hyperthermic perfusion; 3) frequency enhancers; 4) apply heating to the target site using a catheter; 5) injection of magnetic and ferroelectric particles; 6) injection of magnetic nanoparticles that may carry a pharmacological active drug. The use of magnetic nanoparticles is a very promising treatment approach since it may be used for diagnostic and treatment. An ideal magnetic nanoparticle would be able to detect and diagnose the tumor, carry a pharmacological active drug to be delivered in the tumor site, apply hyperthermia through an external magnetic field and allow treatment monitoring by magnetic resonance imaging.

}, keywords = {Cancer treatment, catheter, chemotherapeutic agent, conventional therapies, external magnetic field, heat therapy, Hyperthermia, hyperthermic perfusion, Magnetic nanoparticles, Radio-Frequency}, isbn = {1574-8928/2212-3970}, url = {http://www.eurekaselect.com/node/89176/article}, author = {Paula I P Soares and Ferreira, Isabel and Rui Igreja and Novo, Carlos and Borges, Jo{\~a}o Paulo} } @article {soares2012doxorubicin, title = {Doxorubicin vs. ladirubicin: methods for improving osteosarcoma treatment}, journal = {Mini reviews in medicinal chemistry}, volume = {12}, number = {12}, year = {2012}, pages = {1239{\textendash}1249}, publisher = {Bentham Science Publishers}, abstract = {

Osteosarcoma is the most common primary bone tumor in children and adolescents, with a 5-year disease free survival rate of 70\%. Current chemotherapy regimens comprise a group of chemotherapeutic agents in which doxorubicin is included. However, tumor resistance to anthracyclines and cardiotoxicity are limiting factors for its usage. Liposomal formulations of doxorubicin improve its anti-cancer effects but are still insufficient. The research in this area has lead to the production of anthracyclines analogues, such as ladirubicin, the leading compound of alkylcyclines. This new anticancer agent has shown promising results in vivo and in vitro, being effective against osteosarcoma cell lines, including those with a multidrug resistant phenotype. In phase I clinical trials, this molecule caused mild side effects and did not induce significant cardiotoxicity at doses ranging from 1 to 16 mg/m2, resulting in a peak plasma concentration (Cmax) ranging from 0.5 to 1.5 μM. The recommended doses for phase II studies were 12 and 14 mg/m2 in heavily and minimally pretreated/non-pretreated patients, respectively. Phase II clinical trials in ovary, breast, colorectal cancer, NSCLC and malignant melanoma are underway. Given the improved molecular targeting efficacy of these new compounds, ongoing approaches have sought to improve drug delivery systems, to improve treatment efficacy while reducing systemic toxicity. The combination of these two approaches may be a good start for the discovery of new treatment for osteosarcoma.

}, url = {http://dx.doi.org/10.2174/138955712802762022}, author = {Paula I P Soares and Dias, S{\'e}rgio and Novo, Carlos and Ferreira, Isabel and Borges, Jo{\~a}o Paulo} } @article {franco2012electrospun, title = {Electrospun hydroxyapatite fibers from a simple sol{\textendash}gel system}, journal = {Materials Letters}, volume = {67}, number = {1}, year = {2012}, pages = {233{\textendash}236}, publisher = {Elsevier}, abstract = {

This work reports the production of hydroxyapatite (HA) sub-micron fibers by combining electrospinning and a non-alkoxide sol{\textendash}gel system, using cheap precursors. Phosphorus pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as precursors of phosphorus and calcium, respectively. The fibers were electrospun from a mixture of the gel formed from the system Ca(NO3)2.4H2O/P2O5 with polymeric solutions of polyvinylpyrrolidone (PVP) in water and ethanol/water mixtures. The fibers were analyzed for their morphology (Scanning Electron Microscopy, SEM), chemical composition (Fourier Transform Infrared Spectroscopy, FTIR) and structure (X-ray diffraction, XRD). The fibers obtained were composed mainly of type B carbonated HA with traces of β-tricalcium phosphate (β-TCP). SEM analysis revealed that increasing the concentration of water in the solvent system, used in the preparation of electrospinning solutions, led to fibers with smaller diameters and narrower diameter distribution.

}, url = {10.1016/j.matlet.2011.09.090}, author = {Franco, Patr{\'\i}cia Q and Jo{\~a}o, Carlos and Silva, Jorge Carvalho and Borges, Jo{\~a}o Paulo} } @inbook {borges2011all, title = {All-cellulosic based composites}, booktitle = {Cellulose Fibers: Bio-and Nano-Polymer Composites}, year = {2011}, pages = {399{\textendash}421}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, abstract = {

The use of cellulosic fibers as load bearing constituents in composite materials has increased over the last decade due to their relative cheapness compared to conventional materials such as glass and aramid fibers, their ability to recycle, and because they compete well in terms of strength per weight of material. All-cellulosic based composites prepared from cellulose derivatives based matrices and microcrystalline cellulosic fibers made by direct coupling between fibers and matrix present interesting mechanical and gas permeation properties, thus being potential candidates for packaging materials. Both the cellulosic matrix and the reinforcing fibers are biocompatible and widely used in the pharmaceutical industry, which is very important for the envisaged application. In addition to their biocompatibility, cellulosic systems have the ability to form both thermotropic and lyotropic chiral nematic phases, and the composites produced from the latter show improved mechanical properties due to fiber orientation induced by the anisotropic matrix. The preparation and characterization (morphological, topographical, mechanical, gas barrier properties) of all-cellulosic based composites are described in this chapter.

}, url = {http://link.springer.com/chapter/10.1007/978-3-642-17370-7_15}, author = {Borges, Jo{\~a}o Paulo and Godinho, Maria Helena and Figueirinhas, Joao Luis and de Pinho, MN and Belgacem, Mohamed Naceur}, editor = {Susheel Kalia and B. S. Kaith and Inderjeet Kaur} } @article {7332, title = {Thin and flexible bio-batteries made of electrospun cellulose-based membranes}, journal = {Biosens Bioelectron}, volume = {26}, number = {5}, year = {2011}, pages = {2742-5}, abstract = {

The present work proposes the development of a bio-battery composed by an ultrathin monolithic structure of an electrospun cellulose acetate membrane, over which was deposited metallic thin film electrodes by thermal evaporation on both surfaces. The electrochemical characterization of the bio-batteries was performed under simulated body fluids like sweat and blood plasma [salt solution{\textendash}0.9\% (w/w) NaCl]. Reversible electrochemical reactions were detected through the cellulose acetate structure. Thus, a stable electrochemical behavior was achieved for a bio-battery with silver and aluminum thin films as electrodes. This device exhibits the ability to supply a power density higher than 3 muW cm(-2). Finally, a bio-battery prototype was tested on a sweated skin, demonstrating the potential of applicability of this bio-device as a micropower source.

}, keywords = {*Bioelectric Energy Sources Cellulose/*chemistry Elastic Modulus *Electric Power Supplies Electrochemistry/methods Equipment Design Equipment Failure Analysis *Membranes, Artificial Rotation}, url = {10.1016/j.bios.2010.09.055}, author = {Baptista, Ana Catarina and Martins, J. I. and Elvira Fortunato and Rodrigo Martins and Borges, Jo{\~a}o Paulo and Ferreira, Isabel} } @article {ribeiro2009development, title = {Development of a new chitosan hydrogel for wound dressing}, journal = {Wound repair and regeneration}, volume = {17}, number = {6}, year = {2009}, pages = {817{\textendash}824}, publisher = {Blackwell Publishing Inc}, abstract = {

Wound healing is a complex process involving an integrated response by many different cell types and growth factors in order to achieve rapid restoration of skin architecture and function. The present study evaluated the applicability of a chitosan hydrogel (CH) as a wound dressing. Scanning electron microscopy analysis was used to characterize CH morphology. Fibroblast cells isolated from rat skin were used to assess the cytotoxicity of the hydrogel. CH was able to promote cell adhesion and proliferation. Cell viability studies showed that the hydrogel and its degradation by-products are noncytotoxic. The evaluation of the applicability of CH in the treatment of dermal burns in Wistar rats was performed by induction of full-thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with CH were considerably smaller than those of the controls. Histological analysis revealed lack of a reactive or a granulomatous inflammatory reaction in skin lesions with CH and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may aid the re-establishment of skin architecture.

}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1524-475X.2009.00538.x/full}, author = {Ribeiro, Maximiano P and Espiga, Ana and Silva, Daniela and Baptista, Patricia and Henriques, Joaquim and Ferreira, Catarina and Silva, Jorge Carvalho and Borges, Jo{\~a}o Paulo and Pires, Eduardo and Chaves, Paula and Correia, Il{\'\i}dio J} } @article {almeida2009electro, title = {Electro-optical light scattering shutter using electrospun cellulose-based nano-and microfibers}, journal = {Applied Physics Letters}, volume = {95}, number = {4}, year = {2009}, pages = {043501}, publisher = {AIP Publishing}, abstract = {

Electrospun cellulose-based nano and microfibers and a nematic liquid crystal are used to assemble an electro-optical (EO) light-scattering device that shows enhanced characteristics when compared to similar devices. Based on the controlled scattering of light in the composite system, the device can achieve light transmission coefficients tunable from 1\% up to around 89\%. Simulation of the EO behavior indicates that the roughness of the polymer-liquid crystal interface is crucial for the optical performance of the device.

}, url = {http://scitation.aip.org/content/aip/journal/apl/95/4/10.1063/1.3186640}, author = {Almeida, Pedro L and Kundu, Sudarshan and Borges, Jo{\~a}o Paulo and Godinho, Maria Helena and Figueirinhas, Joao L.} }