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Projeto de investigação
Enhanced Cardiomyocyte Maturation by Electrical Stimulation Based on Conductive Biomaterials for Drug Development
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Influence of CO2 laser beam modelling on electronic and electrochemical properties of paper-based laser-induced graphene for disposable pH electrochemical sensors
Publication . Pinheiro, Tomás; Rosa, André; Ornelas, Cristina; Coelho, João; Fortunato, Elvira; Marques, Ana C.; Martins, Rodrigo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Elsevier BV
Laser-induced graphene (LIG) allows for the fabrication of cost-effective, flexible electrodes on a multitude of recyclable and sustainable substrates, for implementation within electrochemical biosensors. This work expands on current LIG research, by experimentally modeling the effects of several CO2 laser irradiation variables towards resulting conductive and electrochemical properties of paper-derived LIG. Instead of relying on the established paradigm of manipulating power and scan speed of the laser irradiation process for optimized outcomes, modeling of underlying laser operation principles for pulse modulation, regarding pulse repetition frequencies, pulse duration and defocus are presented as the key aspects dominating graphitization processes of materials. This approach shows that graphitization is dominated by appropriate pulse durations, dictating the time the substrate is exposed to each laser pulse, with laser fluence and irradiation defocus influencing the resulting conductive properties, with sheet resistances as low as 14 Ω sq−1. Similarly, fabrication settings controlled by these parameters have a direct influence on the properties of LIG-based electrochemical three-electrode cells, with optimized fabrication settings reaching electrochemically active surface area as high as 35 mm2 and heterogeneous electron transfer rates of 3.4 × 10−3 cm.s−1. As a proof-of-concept, the production of environmentally friendly, accessible, and biocompatible pH sensors is demonstrated, using two modification approaches, employing riboflavin and polyaniline as pH-sensitive elements.
One-step production of laser-induced graphene via CO2 laser on agarose-lignin membranes
Publication . Machado, Beatriz S.; Morais, Maria; Pinheiro, Tomás; Deuermeier, Jonas; Teixeira, Vasco; Nunes, Daniela; Martins, Rodrigo; Inácio, José M.; Fortunato, Elvira; Almeida, Henrique V.; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; NOVA Medical School|Faculdade de Ciências Médicas (NMS|FCM); IOP Publishing
Laser-induced graphene (LIG) is a highly promising material for bioelectronics due to its excellent electrical conductivity, high surface area and biocompatibility. Nevertheless, the functionalization of biocompatible substrates with LIG is essential to propel the use of LIG-derived technologies forward in bioengineering. This study demonstrates the successful fabrication of LIG on agarose-lignin membranes using a single-step CO2 laser process. Membranes with 3 or 5 wt.% agarose, and 0.25 or 0.5 wt.% lignin were characterized for thickness and swelling degree to assess their behavior in a human-mimicking media. The LIG was comprehensively studied, measuring electrical and sheet resistance, and by employing techniques such as Raman spectroscopy, scanning electron microscopy (SEM) coupled with energy-dispersive x-ray spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) to evaluate graphitization efficiency and investigate its physicochemical characteristics. Electrical measurements revealed that the lowest sheet resistance achieved was equal to 139 ± 2 Ω sq−1, with lower laser speeds (below 76.2 mm s−1) and higher power settings (above 2.5 W) leading to improved conductivity. SEM analysis revealed a three-dimensional porous structure with pore sizes ranging from nanometers to micrometers, contributing to enhanced electrical conductivity and suitability for bioelectronic applications. EDS mapping further identified carbon, oxygen, and sodium. XPS analysis provided detailed insights into the chemical states of carbon, indicating high-quality graphene formation. The integration of LIG with these flexible, biocompatible membranes highlights their potential for use in bioelectronic devices, including wearable sensors and implantable medical technologies. These findings underscore the potential of agarose-lignin-based LIG as a scalable, eco-friendly platform for future bioelectronic innovations.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
2022.08597.PTDC