3D printing for biosensors: from fabrication methods towards point-of-care testing devices

3D printing is reshaping the development of electrochemical biosensors by enabling design freedom, rapid prototyping, and low-cost fabrication, making it a strong candidate for point-of-care testing (POCT). Unlike existing reviews that emphasize printing methods, filament composition, or analytical applications, this work critically examines how the fabrication workflow influences biosensor performance, including biofunctionalization efficiency, signal transduction, and reproducibility. The role of surface activation/modification on biointerface stability is analyzed for enzymatic, non-enzymatic, immunosensing, and nucleic-acid-based 3D-printed sensors. Key bottlenecks, including filament heterogeneity, insufficient long-term studies, insufficient reproducibility statements, and scarce validation in real samples, are evaluated. By shifting the focus from analytical performance to biointerface features, this review identifies essential gaps hindering the transition of proof-of-concept to actual POCT devices. Finally, emerging strategies, including custom conductive filament approaches, reagent-free activation strategies, fully integrated 3D-printed electrochemical cells, and wearable architectures are discussed to guide future advancements in the field. • Critical review on 3D-printing fabrication protocols for point-of-care testing (POCT) devices. • We discuss how 3D-printing fabrication workflow affects main biosensors’ properties. • Special focus on enzymatic/non-enzymatic, nucleic-acid-based biosensors and immunosensors. • – Critical gaps on filament heterogeneity, long-term stability, reproducibility, real-world applications. • – Translation of proof-of-concept to actual POCT devices is discussed and perspectives stated.