One-step production of laser-induced graphene via CO 2 laser on agarose–lignin membranes

• Published in: Flexible and printed electronics Vol. 10; no. 2; p. 25011
• Main Authors: Machado, Beatriz S, Morais, Maria, Pinheiro, Tomás, Deuermeier, Jonas, Teixeira, Vasco, Nunes, Daniela, Martins, Rodrigo, Inácio, José M, Fortunato, Elvira, Almeida, Henrique V
• Format: Journal Article
• Language: English
• Published: 01.06.2025
• ISSN: 2058-8585; 2058-8585
• DOI: 10.1088/2058-8585/ade167

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 CO 2 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.