Nélson Castro

University of Minho

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Co-Authors

S. Lanceros‐Méndez

Ikerbasque

V. Correia

Universidade do Porto

Clarisse Ribeiro

Universidade Federal de Juiz de Fora

Margarida M. Fernandes

University of Minho

Nélson Pereira

Centro Hospitalar do Tâmega e Sousa

M.P. Silva

University of Beira Interior

Pedro Costa

University of Minho

P. Martins

University of Minho

S. Reis

University of Aveiro

José Luis Vilas‐Vilela

University of the Basque Country

Cooperative Institutions

University of Minho

Basque Center for Materials, Applications and Nanostructures

Clinical Academic Center of Braga

University of the Basque Country

International Iberian Nanotechnology Laboratory

Ikerbasque

Euskadiko Parke Teknologikoa

Departamento de Ciência e Tecnologia

Vitenparken

Universidade do Porto

Author Statistics

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Research Field

Marked Object Recognition Multitouch Screen Printed Touchpad for Interactive Applications

Sensors (2017)

J. Serrado Nunes Nélson Castro Sérgio Gonçalves Nélson Pereira V. Correia

The market for interactive platforms is rapidly growing, and touchscreens have been incorporated in an increasing number of devices. Thus, the area of smart objects and devices is strongly increasing by adding interactive touch and multimedia content, leading to new uses and capabilities. In this work, a flexible screen printed sensor matrix is fabricated based on silver ink in a polyethylene terephthalate (PET) substrate. Diamond shaped capacitive electrodes coupled with conventional capacitive reading electronics enables fabrication of a highly functional capacitive touchpad, and also allows for the identification of marked objects. For the latter, the capacitive signatures are identified by intersecting points and distances between them. Thus, this work demonstrates the applicability of a low cost method using royalty-free geometries and technologies for the development of flexible multitouch touchpads for the implementation of interactive and object recognition applications.

Touchpad

10.3390/s17122786

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Citations (10)

Design, Construction and Validation of a New Generation of Bioreactors for Tissue Engineering Applications.

Nélson Castro

Source

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Citations (0)

Magnetically Activated Electroactive Microenvironments for Skeletal Muscle Tissue Regeneration

ACS Applied Bio Materials (2020)

Sylvie Ribeiro Clarisse Ribeiro Estela O. Carvalho Carmen R. Tubío Nélson Castro

This work reports on magnetoelectric biomaterials suitable for effective proliferation and differentiation of myoblast in a biomimetic microenvironment providing the electromechanical stimuli associated with this tissue in the human body. Magnetoelectric films are obtained by solvent casting through the combination of a piezoelectric polymer, poly(vinylidene fluoride-trifluoro-ethylene), and magnetostrictive particles (CoFe2O4). The nonpoled and poled (with negative and positive surface charge) magnetoelectric composites are used to investigate their influence on C2C12 myoblast adhesion, proliferation, and differentiation. It is demonstrated that the proliferation and differentiation of the cells are enhanced by the application of mechanical and/or electrical stimulation, with higher values of maturation index under mechanoelectrical stimuli. These results show that magnetoelectric cell stimulation is a full potential approach for skeletal muscle tissue engineering applications.

10.1021/acsabm.0c00315

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Citations (52)

Triboelectric Energy Harvesting Response of Different Polymer-Based Materials

Materials (2020)

T. Rodrigues-Marinho Nélson Castro V. Correia Pedro Costa S. Lanceros‐Méndez

Energy harvesting systems for low-power devices are increasingly being a requirement within the context of the Internet of Things and, in particular, for self-powered sensors in remote or inaccessible locations. Triboelectric nanogenerators are a suitable approach for harvesting environmental mechanical energy otherwise wasted in nature. This work reports on the evaluation of the output power of different polymer and polymer composites, by using the triboelectric contact-separation systems (10 N of force followed by 5 cm of separation per cycle). Different materials were used as positive (Mica, polyamide (PA66) and styrene/ethylene-butadiene/styrene (SEBS)) and negative (polyvinylidene fluoride (PVDF), polyurethane (PU), polypropylene (PP) and Kapton) charge materials. The obtained output power ranges from 0.2 to 5.9 mW, depending on the pair of materials, for an active area of 46.4 cm2. The highest response was obtained for Mica with PVDF composites with 30 wt.% of barium titanate (BT) and PA66 with PU pairs. A simple application has been developed based on vertical contact-separation mode, able to power up light emission diodes (LEDs) with around 30 cycles to charge a capacitor. Further, the capacitor can be charged in one triboelectric cycle if an area of 0.14 m2 is used.

Polyvinylidene fluoride

Contact electrification

Mechanical energy

Polypropylene

Ferroelectric Polymers

10.3390/ma13214980

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Citations (24)

Silk Fibroin Magnetoactive Nanocomposite Films and Membranes for Dynamic Bone Tissue Engineering Strategies

SSRN Electronic Journal (2020)

Ander Reizabal Ricardo Brito‐Pereira Margarida M. Fernandes Nélson Castro V. Correia

Bone-related diseases are one of the most common health conditions that limit the quality of life of elderly. Novel materials for bone tissue engineering that actively assist on the regeneration of bone tissue are thus needed. In this work, magnetoactive scaffolds comprised of silk fibroin (SF) with different content of filler- cobalt ferrite nanoparticles- were produced by solvent-casting and electrospinning technique and further evaluated for bone cells growth under static and dynamic magnetic stimulation. The materials were evaluated for their enhanced electric properties, analyzed through the silk fibroin β-sheet content, an important factor for the envisaged cell stimulation strategy, which are in much higher content in films (~50%) than in electrospun fibres (~25%). Cell culture experiments under varying magnetic field, induced a magneto-mechanical stimulation on the materials, hence on cells, promoting improved cell viability after 4 days of culture. The scaffold morphology was found to play an important role in pre-osteoblast proliferation rate, being larger for cells growing on films, which is related to the topography of the material but also to the increased β-sheet content. It is shown that the use of magnetic cues on magnetoactive biocompatible scaffolds is a promising strategy for remote stimulation of bone for its regeneration.

Fibroin

10.2139/ssrn.3539234

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Citations (1)

Physically Active Bioreactors for Tissue Engineering Applications

Advanced Biosystems (2020)

Nélson Castro Sylvie Ribeiro Margarida M. Fernandes Clarisse Ribeiro Vanessa F. Cardoso

Abstract Tissue engineering (TE) is a strongly expanding research area. TE approaches require biocompatible scaffolds, cells, and different applied stimuli, which altogether mimic the natural tissue microenvironment. Also, the extracellular matrix serves as a structural base for cells and as a source of growth factors and biophysical cues. The 3D characteristics of the microenvironment is one of the most recognized key factors for obtaining specific cell responses in vivo, being the physical cues increasingly investigated. Supporting those advances is the progress of smart and multifunctional materials design, whose properties improve the cell behavior control through the possibility of providing specific chemical and physical stimuli to the cellular environment. In this sense, a varying set of bioreactors that properly stimulate those materials and cells in vitro, creating an appropriate biomimetic microenvironment, is developed to obtain active bioreactors. This review provides a comprehensive overview on the important microenvironments of different cells and tissues, the smart materials type used for providing such microenvironments and the specific bioreactor technologies that allow subjecting the cells/tissues to the required biomimetic biochemical and biophysical cues. Further, it is shown that microfluidic bioreactors represent a growing and interesting field that hold great promise for achieving suitable TE strategies.

Biocompatible material

10.1002/adbi.202000125

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Citations (44)

Magnetic Bioreactor for Magneto-, Mechano- and Electroactive Tissue Engineering Strategies

Sensors (2020)

Nélson Castro Margarida M. Fernandes Clarisse Ribeiro V. Correia Rikardo Mínguez

Biomimetic bioreactor systems are increasingly being developed for tissue engineering applications, due to their ability to recreate the native cell/tissue microenvironment. Regarding bone-related diseases and considering the piezoelectric nature of bone, piezoelectric scaffolds electromechanically stimulated by a bioreactor, providing the stimuli to the cells, allows a biomimetic approach and thus, mimicking the required microenvironment for effective growth and differentiation of bone cells. In this work, a bioreactor has been designed and built allowing to magnetically stimulate magnetoelectric scaffolds and therefore provide mechanical and electrical stimuli to the cells through magnetomechanical or magnetoelectrical effects, depending on the piezoelectric nature of the scaffold. While mechanical bioreactors need direct application of the stimuli on the scaffolds, the herein proposed magnetic bioreactors allow for a remote stimulation without direct contact with the material. Thus, the stimuli application (23 mT at a frequency of 0.3 Hz) to cells seeded on the magnetoelectric, leads to an increase in cell viability of almost 30% with respect to cell culture under static conditions. This could be valuable to mimic what occurs in the human body and for application in immobilized patients. Thus, special emphasis has been placed on the control, design and modeling parameters governing the bioreactor as well as its functional mechanism.

Magneto

10.3390/s20123340

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Citations (32)

Electronic optimization for an energy harvesting system based on magnetoelectric Metglas/poly(vinylidene fluoride)/Metglas composites

Smart Materials and Structures (2016)

S. Reis M.P. Silva Nélson Castro V. Correia J. G. Rocha

Harvesting magnetic energy from the environment is becoming increasingly attractive for being a renewable and inexhaustible power source, ubiquitous and accessible in remote locations. In particular, magnetic harvesting with polymer-based magnetoelectric (ME) materials meet the industry demands of being flexible, showing large area potential, lightweight and biocompatibility. In order to get the best energy harvesting process, the extraction circuit needs to be optimized in order to be useful for powering devices. This paper discusses the design and performance of five interface circuits, a full-wave bridge rectifier, two Cockcroft–Walton voltage multipliers (with 1 and 2 stages) and two Dickson voltage multipliers (with 2 and 3 stages), for the energy harvesting from a Fe61.6Co16.4Si10.8B11.2 (Metglas)/polyvinylidene fluoride/Metglas ME composite. Maximum power and power density values of 12 μW and 0.9 mW cm−3 were obtained, respectively, with the Dickson voltage multiplier with two stages, for a load resistance of 180 kΩ, at 7 Oe DC magnetic field and a 54.5 kHz resonance frequency. Such performance is useful for microdevice applications in hard-to-reach locations and for traditional devices such as electric windows, door locking, and tire pressure monitoring.

Metglas

Rectifier (neural networks)

10.1088/0964-1726/25/8/085028

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Citations (50)

Improving Definition of Screen-Printed Functional Materials for Sensing Application

ACS Applied Electronic Materials (2024)

Lia Campos‐Arias Nikola Peřinka Yin Cheung Lau Nélson Castro Nélson Pereira

Screen printing is one of the most used techniques for developing printed electronics. It stands out for its simplicity, scalability, and effectivity. Specifically, the manufacturing of hybrid integrated circuits has promoted the development of the technique, and the photovoltaic industry has enhanced the printing process by developing high-performance metallization pastes and high-end screens. In recent years, fine lines of 50 μm or smaller are about to be adopted in mass production, and screen printing has to compete with digital printing techniques such as inkjet printing, which can reach narrower lines. In this sense, this work is focused on testing the printing resolution of a high-performance stainless-steel screen with commercial conductive inks and functional lab-made inks based on reduced graphene oxide using an interdigitated structure. We achieved electrically conductive functional patterns with a minimum printing resolution of 40 μm for all inks.

Screen printing

Printed Electronics

Conductive ink

Inkjet Printing

Digital printing

10.1021/acsaelm.3c01415

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Citations (2)

A 3D-Printed Portable UV and Visible Photoreactor for Water Purification and Disinfection Experiments

Nanomaterials (2024)

Nélson Castro Joana M. Queirós Dinis C. Alves Margarida M. Fernandes S. Lanceros‐Méndez

Water scarcity and contamination are urgent issues to be addressed. In this context, different materials, techniques, and devices are being developed to mitigate contemporary and forthcoming water constraints. Photocatalysis-based approaches are suitable strategies to address water contamination by degrading contaminants and eliminating microbes. Photoreactors are usually designed to perform photocatalysis in a scalable and standardised way. Few or none have been developed to combine these characteristics with portability, flexibility, and cost effectiveness. This study reports on designing and producing a portable (490 g), low-cost, and multifunctional photoreactor that includes adjustable radiation intensity and two types of wavelengths (UV-A and visible), including combined agitation in a compact mechanism produced through 3D printing technology. The mechanical, electrical, and optical subsystems were designed and assembled into a robust device. It is shown that it is possible to apply radiations that can reach 65 mW/cm

Software portability

Visible spectrum

10.3390/nano14060525

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Citations (0)