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This paper reports on single step and rapid fabrication of interdigitated electrodes (IDEs) using an inkjet printing-based approach. A commercial inkjet-printed circuit board (PCB) printer was used to fabricate the IDEs on a glass substrate. The inkjet printer was optimized for printing IDEs on a glass substrate using a carbon ink with a specified viscosity. Electrochemical impedance spectroscopy in the frequency range of 1 Hz to 1 MHz was employed for chemical sensing applications using an electrochemical workstation. The IDE sensors demonstrated good nitrite quantification abilities, detecting a low concentration of 1 ppm. Taste simulating chemicals were used to experimentally analyze the ability of the developed sensor to detect and quantify tastes as perceived by humans. The performance of the inkjet-printed IDE sensor was compared with that of the IDEs fabricated using maskless direct laser writing (DLW)-based photolithography. The DLW–photolithography-based fabrication approach produces IDE sensors with excellent geometric tolerances and better sensing performance. However, inkjet printing provides IDE sensors at a fraction of the cost and time. The inkjet printing-based IDE sensor, fabricated in under 2 min and costing less than USD 0.3, can be adapted as a suitable IDE sensor with rapid and scalable fabrication process capabilities.

Controlled, stable and uniform temperature environment with quick response are crucial needs for many lab-on-chip (LOC) applications requiring thermal management. Laser Induced Graphene (LIG) heater is one such mechanism capable of maintaining a wide range of steady state temperature. LIG heaters are thin, flexible, and inexpensive and can be fabricated easily in different geometric configurations. In this perspective, herein, the electro-thermal performance of the LIG heater has been examined for different laser power values and scanning speeds. The experimented laser ablated patterns exhibited varying electrical conductivity corresponding to different combinations of power and speed of the laser. The conductivity of the pattern can be tailored by tuning the parameters which exhibit, a wide range of temperatures making them suitable for diverse lab-on-chip applications. A maximum temperature of 589 °C was observed for a combination of 15% laser power and 5.5% scanning speed. A LOC platform was realized by integrating the developed LIG heaters with a droplet-based microfluidic device. The performance of this LOC platform was analyzed for effective use of LIG heaters to synthesize Gold nanoparticles (GNP). Finally, the functionality of the synthesized GNPs was validated by utilizing them as catalyst in enzymatic glucose biofuel cell and in electrochemical applications.