Substrate-Independent Laser-Induced Graphene Electrodes for Microfluidic Electroanalytical Systems

Abstract

Laser-induced graphene’s (LIG) inherent graphene-like and highly porous characteristics and its simple, scalable, and inexpensive fabrication render it a desirable electrode material for bio- and chemosensors. The best LIG electrodes are made in polyimide foils using a CO2 laser scriber, which unfortunately limits their integration into more sophisticated analytical devices due to polyimide’s inertness. The transfer of LIG electrodes onto standard polymer substrates used in microfluidic systems and their use in microfluidic assays were therefore studied and the resulting electrodes characterized morphologically, chemically, and electroanalytically. It was found that a direct pressure-driven transfer produces highly functional transfer-LIG (tLIG) electrodes. tLIG differed from LIG electrodes with respect to a much smoother surface and hence a lower active surface area, a loss of the graphene characteristic Raman 2D peak, and a slight decrease in electron transfer rates. However, their performance in amperometric detection strategies were comparable also when used in adhesive-tape-enabled microfluidic channels for the detection of p-aminophenol. tLIG outperformed LIG electrodes in their ability to be integrated into more advanced microfluidic channel systems made of an all-polymethyl methacrylate (PMMA) substrate for the biosensing detection of alkaline phosphatase, commonly used as a biomarker and as a biosensor amplification system. LIG and tLIG have hence the potential to change electroanalytical sensing in diagnostic systems as their fabrication requires minimal resources, is highly scalable, and allows their integration into simple and, as tLIG, also sophisticated analytical systems.

Laser-induced graphene (LIG)-driven medical sensors for health monitoring and diseases diagnosis

“…It was also applied in energy storage micro-supercapacitors (MSCs) [ 24 , 26 ], cell culture [ 27 ], and fuel cell [ 28 ]. Meanwhile, LIG possesses characteristics such as flexibility, chemical resistance, and porosity, which makes useful as a porous channel or electrode material in microfluidic devices [ 29 ]. The various applications of LIG are shown in Fig.…”

Miniaturized sensor for electroanalytical and electrochemiluminescent detection of pathogens enabled through laser-induced graphene electrodes embedded in microfluidic channels

“…12 In one of their previous studies, Griesche et al have demonstrated the integration of laser-induced graphene electrodes into a laminated microfluidic device for sensitive electrochemical detection. 13 Laser-induced graphene is a porous, graphene-like carbon material that is created by laser irradiation of a precursor material under ambient conditions. 14 The most common precursor material is commercially available polyimide foil, 14 but researchers also demonstrated LIG formation on other polymers 15,16 and carbon-based materials like wood, 17 cloth, paper and food.…”

Compacted Laser‐Induced Graphene with Bamboo‐Like Carbon Nanotubes for Transformable Capacitive Energy Storage Electrodes

“…Laser-assisted techniques enable high processing efficiency in the production of 3D-structured graphene owing to the very short synthesis time and simple patterning process. [21] For this reason, LIG is widely used in the fields of chemical sensors, [22] triboelectric nanogeneratoers, [23] microfluidic devices, [24] electrocatalysts, [25] and especially supercapacitors. [17,18,[26][27][28][29] The LIG-based materials have demonstrated high performance in energy storage applications due to its excellent electrical conductivity (25 S cm −1 ), specific surface area (340 m 2 g −1 ), and tunable properties.…”