Tuning the Structure, Conductivity, and Wettability of Laser-Induced Graphene for Multiplexed Open Microfluidic Environmental Biosensing and Energy Storage Devices

Abstract

The integration of microfluidics and electrochemical cells is at the forefront of emerging sensors and energy systems; however, a fabrication scheme that can create both the microfluidics and electrochemical cells in a scalable fashion is still lacking. We present a one-step, mask-free process to create, pattern, and tune laser-induced graphene (LIG) with a ubiquitous CO2 laser. The laser parameters are adjusted to create LIG with different electrical conductivity, surface morphology, and surface wettability without the need for postchemical modification. Such definitive control over material properties enables the creation of LIG-based integrated open microfluidics and electrochemical sensors that are capable of dividing a single water sample along four multifurcating paths to three ion selective electrodes (ISEs) for potassium (K+), nitrate (NO3 –), and ammonium (NH4 +) monitoring and to an enzymatic pesticide sensor for organophosphate pesticide (parathion) monitoring. The ISEs displayed near-Nernstian sensitivities and low limits of detection (LODs) (10–5.01 M, 10–5.07 M, and 10–4.89 M for the K+, NO3 –, and NH4 + ISEs, respectively) while the pesticide sensor exhibited the lowest LOD (15.4 pM) for an electrochemical parathion sensor to date. LIG was also specifically patterned and tuned to create a high-performance electrochemical micro supercapacitor (MSC) capable of improving the power density by 2 orders of magnitude compared to a Li-based thin-film battery and the energy density by 3 orders of magnitude compared to a commercial electrolytic capacitor. Hence, this tunable fabrication approach to LIG is expected to enable a wide range of real-time, point-of-use health and environmental sensors as well as energy storage/harvesting modules.

Electrooculography and Tactile Perception Collaborative Interface for 3D Human–Machine Interaction

“…In addition, there are still challenges in the interconnection and protection of ultrathin bare GETs. , Consequently, it is of great significance to develop ultrathin, flexible, stretchable, and air permeable graphene electrodes with simple preparation. Laser-induced graphene, with its simple preparation, is widely used in wearable electronics, such as strain sensors, − microfluidic biosensors, , electromagnetic interference shields, , multifunctional textiles, , etc. The development of a special transfer process combined with a laser induction process is helpful to realize the ultrathin graphene electrode for EOG signal acquisition.…”

Development of a Biosensor Based on Angiotensin‐Converting Enzyme II for Severe Acute Respiratory Syndrome Coronavirus 2 Detection in Human Saliva

“…Amongst the advantages of using LIG over commercial electrodes, we can cite the following: 1) Customizable design of the electrodes’ size and shape: the electrode can be digitally designed according to the project needs using any vector graphics software (e.g., CorelDRAW). The CO 2 laser can inscribe any pattern of the polymeric surface with micrometer resolution ( Ye et al, 2019 ; Soares et al, 2020 ); 2) Tunable electrode properties: by adjusting the laser inscribing parameters it is possible to modify material properties such as electrical conductivity, surface morphology, and surface wettability without the need for post-chemical modification ( Ye et al, 2019 ; Chen et al, 2022 ; Hjort et al, 2022 ); 3) Simplified manufacturing: LIG electrodes fabrication is a one-step process based on CO 2 -laser inscribing on a polyimide substrate. Fabricated electrodes can be further functionalized with nanoparticles and biomaterials according to the project needs ( Ye et al, 2019 ); 4) Low-cost: the lab manufacturing cost of the LIG electrodes described in this work is less than $1 USD a piece.…”

Surface Wettability for Skin‐Interfaced Sensors and Devices

“…[113] Efforts to address the challenges lead to the development of a mask-free laser scribing strategy to directly create wettability contrast on-demand by tuning both the surface morphology and chemical composition. [114][115][116] For example, the superwettability patterns with superhydrophilic porous graphene and superhydrophobic layered graphite on the PI substrate are prepared by laser scribing the target region of the substrate at low or high power, respectively. [114] Moreover, laser-induced heating can remove the low-surface-energy reagent to result in superhydrophilic regions on the superhydrophobic substrate.…”