Recent developments in nanotechnology-based printing electrode systems for electrochemical sensors

In this review, the state-of-the-art of screen, inkjet, and three-dimensional (3D) printing electrode technologies of diverse types, manufacturing processes, and applications are critically reviewed for the first time. Emerging printing electrode-based technologies for advanced fabrication of printed electrode materials have given rise to the development of printed electrode devices and systems, thereby opening new avenues for several electrochemical applications. Additionally, their properties can be fine-tuned for specific electrochemical applications by embedding and/or immobilizing nano-structured materials. Nano-based printed or modified electrodes exhibit attractive features such as enhanced performance, cost-effectiveness, scalability, and high selectivity towards various targeted electroactive analytes. Furthermore, these nano-sized printed electrodes are flexible and portable, and thus are applicable for on-site measurements. However, their performance is affected by the type of printed electrode materials and fabrication methods employed. Hence, this review delves on the various electrode materials, printing methods and their applications for biosensors as well as for the detection of organic and inorganic compounds. The printed electrode materials that focus on properties such as selectivity, sensitivity and limit of detection available in the literature are highlighted in this review. Finally, future prospects, possibilities, and challenges of these advanced printing electrode technologies are deliberated.