3D-Engineered Electroactive Biosensors for Rapid and Sensitive Detection of Environmental Contaminants

The growing concern about water pollution has intensified the demand for rapid and sensitive pollutant monitoring. Electroactive biosensors (e-biosensors) hold significant potential in detecting toxic pollutants through bioelectrical signal responses but are constrained by inefficient electron and mass transport within conventional biofilm-based architectures. Here, we address both limitations by developing a 3D-engineered e-biosensor with a synergistically optimized material composition and geometric architecture. A novel electroactive living material was fabricated by incorporating Ca²⁺-doped PEDOT:PSS to enhance microbial extracellular electron transport. The living material was then engineered into a grid-structure e-biosensor by extrusion-based 3D bioprinting, significantly improving analyte mass transport to the sensing cells. This dual optimization resulted in the 3D-engineered e-biosensor exhibiting a 6.3-fold increase in baseline current, a 1.9-fold improvement in signal-to-noise ratio, and an extended operational stability (>140 h) relative to conventional biofilm-based counterparts. Moreover, the 3D-engineered e-biosensors demonstrated a rapid response (<20 min) to various toxic pollutants, including Cr(VI) and nitrobenzene. Additionally, we constructed a portable device integrating the 3D-engineered e-biosensors and successfully validated its effectiveness and reproducibility for pollution monitoring in real waters. This work establishes a new paradigm for e-biosensor engineering by integrating materials science and digital biomanufacturing, offering an innovative solution for water pollution monitoring.