Glycosylation-Engineered Chitosan Bioelectronic Interfaces for P. aeruginosa Gradient Analysis

Point-of-care diagnostics for pathogen detection are crucial for informed clinical pretreatment strategies, rendering the emergence of electro-fluidic systems increasingly attractive. However, both optical and electrical sensing strategies still face challenges in achieving high sensitivity and specificity. Herein, we present a facile and general approach for effectively integrating an electro-fluidic device that enables optical-electrical dual-mode gradient analysis of bacterial populations, mediated by a 2-lactobionamidoethyl methacrylate (SLM)-functionalized chitosan film (CS). Notably, this rationally synthesized CS@SLM exhibits robust interfacial monolayer adsorption performance, serving as a versatile sensing platform for specific bacterial recognition, uniform capture, and rapid accumulation of Pseudomonas aeruginosa. Furthermore, the biointerface demonstrates distinct concentration-dependent adsorption behavior, particularly in diluted bacterial solutions, achieving remarkably high removal efficiencies (78.3–100%) while facilitating bacterial detection at ultralow concentrations (≤101 CFU/mL, 0–10 min). These characteristics enable the creation of a pronounced concentration gradient through subsequent diffusion processes in microfluidic channels, allowing for differential analysis of bacterial populations with thousands of fold enhancement in signal variation. Importantly, the surface-immobilized bacteria retain their bioactivities and can be effectively integrated with electrodes via the engineered biointerface, highlighting significant potential for electro-fluidic multimodal sensing systems. Collectively, this general strategy and versatile biointerface provide new insights into designing advanced electro-fluidic devices for precise bacterial density control and effective infection management.