Publications by authors named "Ricardo Brito-Pereira"

Transient electronics, designed to disintegrate in a controlled manner after their useful life, have been proposed as a solution to mitigate the ecological and health impacts of electronic waste (e-waste). Despite this innovative approach, which has seen significant application in biologically integrated sensors and therapeutic devices, it still results in the accumulation of different materials and nanomaterials for the powering systems often based on batteries, which themselves contribute to the e-waste problem. Here, we explore the use of the silk cocoon from as a key component in the development of environmentally friendly all-silk electronics-based biobatteries.

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An electronic tongue is a sensor-based system designed to mimic human taste by detecting and analyzing the chemical properties of liquids through electrochemical methods. Here, we introduce the HITS concept, an electronic tongue system that enables rapid and sequential classification of various beverages. This system utilizes a single, cost-effective platform with interdigital electrodes made of carbon printed on recyclable poly(ethylene terephthalate) (PET), significantly reducing the need for multiple electrodes.

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Point-of-care (POC) devices can provide inexpensive, practical, and expedited solutions for applications ranging from biomedicine to environmental monitoring. This work reports on the development of low-cost microfluidic substrates for POC systems suitable for analytical assays, while also satisfying the need for social and environmentally conscious practices regarding circular economy, waste reduction, and the use of local resources. Thus, an innovative greener process to extract cellulose from plants including abaca, cotton, kozo, linen, and sisal, originating from different places around the world, is developed, and then the corresponding paper substrates are obtained to serve as platforms for POC assays.

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The continuous rising of infections caused by multidrug-resistant pathogens is becoming a global healthcare concern. Developing new bio-based materials with unique chemical and structural features that allow efficient interaction with bacteria is thus important for fighting this phenomenon. To address this issue, we report an antimicrobial biomaterial that results from clustering local facial amphiphilicity from amino-modified cellulose on silk fibroin β-sheets, by simply blending the two components through casting technology.

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Silk fibroin (SF) is a biocompatible natural protein with excellent mechanical characteristics. SF-based biomaterials can be structured using a number of techniques, allowing the tuning of materials for specific biomedical applications. In this study, SF films, porous membranes, and electrospun membranes were produced using solvent-casting, salt-leaching, and electrospinning methodologies, respectively.

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Tissue engineering (TE) aims to develop structures that improve or even replace the biological functions of tissues and organs. Mechanical properties, physical-chemical characteristics, biocompatibility, and biological performance of the materials are essential factors for their applicability in TE. Poly(vinylidene fluoride) (PVDF) is a thermoplastic polymer that exhibits good mechanical properties, high biocompatibility and excellent thermal properties.

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Portable analytical systems are increasingly required for clinical analysis or environmental monitoring, among others, being materials with tailored physicochemical properties among the main needs for successful functional implementation. This article describes the processing of fluorinated poly(vinylidene--trifluorethylene), P(VDF-TrFE), membranes with tailored morphological and physicochemical properties to be used as microfluidic substrates for portable analytical systems, commonly called point-of-care systems in the medical field. The morphology of the developed membranes includes spherulitic, porous, randomly oriented, and oriented fibers.

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Novel microfluidic substrates based on electrospun poly(l-lactic acid) (PLLA) membranes were developed to increase the limited range of commercially available paper substrates, commonly used for the fabrication of microfluidic paper-based analytical devices. PLLA's advantageous properties include biodegradability, biocompatibility, ease of being processed in various tailored morphologies, and cost effectiveness, among others. Oriented and nonoriented electrospun PLLA membranes were fabricated using electrospinning and the influence of fiber orientation, addition of hydrophilic additives, and plasma treatments on the morphology, physicochemical properties, and capillary flow rates were evaluated and compared with the commercial Whatman paper.

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Environmental issues promote the development of sensors based on natural polymers which are becoming an area of increasing interest. Piezoresistive sensors based on silk fibroin with carbon nanotubes (CNTs) as fillers were produced by solvent-casting in order to tune their electrical conductivity and electromechanical responses. It is shown that the carbonaceous fillers are well dispersed in the polymer matrix and the thermal and mechanical properties are independent of the CNT content.

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Battery separators based on silk fibroin (SF) have been prepared aiming at improving the environmental issues of lithium-ion batteries. SF materials with three different morphologies were produced: membrane films (SF-F), sponges prepared by lyophilization (SF-L), and electrospun membranes (SF-E). The latter materials presented a suitable porous three-dimensional microstructure and were soaked with a 1 M LiPF electrolyte.

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