A review on thermoplastic electrodes: From fabrication to electrochemical (Bio)sensing applications

Thermoplastic Electrodes (TPEs) are widely explored for electroanalysis due to their intrinsic characteristics, including affordability, potential scalability, and versatility. The electrode composition typically consists of a carbon source with a thermoplastic polymer, generating a conductive composite that can be easily molded upon heating. This feature enables the replication of electrode patterns in different shapes and sizes. This adaptability in design allows the integration of TPEs with other analytical systems operating under hydrodynamic conditions, such as microfluidic devices, expanding their applicability in electrochemical sensing. This review provides an overview of thermoplastic electrodes, starting with the historical development of carbon paste electrodes (CPEs). While most recent review articles focus only on 3D printing fabrication, we adopt a broader perspective by exploring alternative methods, such as templating and hot embossing. Insights into each technique are discussed, raising its respective advantages and limitations. We further discuss the thermoplastic composite composition, comparing the electrochemical performance of commercial and lab-made thermoplastic composites. In this sense, fabrication methods for thermoplastic composites are also considered, including approaches for filament production. Finally, recent advancements in electrochemical (bio)sensors are discussed, highlighting the potential of TPEs for future diagnostic applications. Given their cost-effectiveness and simplicity of fabrication, this review article will further encourage the development of new TPEs, specifically in resource-limited laboratories, fostering greater accessibility to practical analytical solutions.