Just as embroiderers, with needle and thread, can transform plain fabric into an intricate pattern, engineers can use lasers and polymers to create flexible, complex structures that could transform life-saving sensing technology. An interdisciplinary team at the University of Pittsburgh\u2019s Swanson School of Engineering has developed a new manufacturing strategy that reveals where and how laser-induced graphene (LIG) forms on polymers.<\/p>\n
The research opens new opportunities for flexible microelectrodes and neurochemical biosensors.<\/p>\n
\u00a0\u201cMiniaturizing Laser-Induced Graphene for Biosensors by Spatial Control of Initiation and Side-Selective Microfabrication on Commercial Polymers<\/a>\u201d (DOI: 10.1002\/admt.202502433<\/a>) was selected as a cover feature in Issue 7 of the Advanced Materials Technologies, published in April 2026.<\/p>\n \u201cGraphene is an ultrathin form of carbon that conducts electricity extremely well, which makes it a powerful material for building flexible sensors and bioelectronic devices,\u201d said Mostafa Bedewy<\/a>, associate professor of mechanical engineering and materials science<\/a> at the Swanson School and senior author.<\/p>\n Although there are many ways to produce graphene, researchers are increasingly turning to laser technology to carbonize polyimides, a flexible form of polymer, producing the conductive, porous material. Controlling this process at the microscale, however, has been a challenge.<\/p>\n By applying a layer of iron-oxide-based ink to the surface of the polymer prior to near-infrared pulsed laser processing, the Pitt researchers established a tunable tradeoff between electrode thickness and electrical performance. Using computer modeling, they discovered how localized thermal gradients drive graphene growth and thinning, providing predictive insights into the relationships that define LIG functionality.<\/p>\n The researchers revealed how controlling the initial point of carbonization governs graphene electrode line thickness, conductivity, and location. They also fabricated graphene on the top, bottom, or both surfaces of a polymer film, dramatically expanding how it could be used for sensing technology.<\/p>\n \u201cRather than only focusing on making graphene microelectrodes as thin as possible, this work set out to understand and control how graphene forms during laser processing from a laser-matter interaction perspective,\u201d said Bedewy. \u201cAfter we understand that process science, we can optimize variables like thickness, conductivity, and device function.\u201d<\/p>\n The resulting graphene microelectrodes combine mechanical flexibility with robust electrical and electrochemical performance, enabling sensitive electrochemical detection of neurotransmitters such as dopamine and serotonin. Importantly, the approach avoids lithography and cleanroom processing, which are more complex and expensive, making it compatible with scalable and low-cost manufacturing.<\/p>\n \u201cSide-selective graphene formation is particularly exciting for bioelectronics,\u201d said Tracy Cui<\/a>, professor of bioengineering<\/a> at the Swanson School and a collaborator on the project. \u201cBeing able to choose which surface of a soft polymer becomes electrically or electrochemically active expands the design space for neural probes, chemical sensors, and implantable devices.\u201d<\/p>\n The work was led by Soumalya Ghosh<\/a>, a PhD student in mechanical engineering who developed the experimental workflows and linked processing conditions to material structure, properties, and electrochemical performance.<\/p>\n \u201cWhat stood out was how graphene properties sensitively respond to the way carbonization is initiated,\u201d said Ghosh. \u201cBy tuning that initiation step, we can balance electrode thickness and conductivity to meet the needs of different sensing applications.\u201d<\/p>\n These findings dovetail with another recent study led by Bedewy and Cui, which showed that laser scanning strategy itself is a powerful control parameter for tuning electrochemical performance in laser-induced graphene biosensors. In that work<\/a>, published in the January 2026 issue of ACS Applied Materials & Interfaces, the researchers demonstrated that speed-dependent sequential laser irradiation can significantly lower electrode impedance and boost sensing sensitivity by modifying graphene morphology and electrochemical interfaces.<\/p>\n Together, these studies highlight how laser processing can be deliberately engineered to optimize the fabrication of graphene-based electrodes with tailored properties for next-generation flexible and implantable bioelectronic devices.<\/p>\n \u201cThis research reflects the type of collaborative environment that thrives here in the Swanson School,\u201d said William (Buddy) Clark<\/a>, professor and interim chair of mechanical engineering and materials science. \u201cFlexible electronics have always been a challenge, so I\u2019m excited to see how this important project evolves.\u201d<\/p>\n Beyond neurotransmitter detection, the researchers envision the process being extended to other flexible electronics, wearable sensors, and multifunctional biointerfaces where spatial control of material properties is critical.<\/p>\n