Development of a Sensitive Diagnostic Device Based on Zeolitic Imidazolate Frameworks‑8 Using Ferrocene–Graphene Oxide as Electroactive Indicator for Pseudomonas aeruginosa Detection

Since Gram-negative bacteria have a predominant role in nosocomial infections, there are high demands to develop a fast and sensitive method for diagnosis of bacteria in clinical samples. To address this challenge, we designed a novel electrochemical biosensor based on aptamers immobilized in engineered zeolitic imidazolate Framework-8 (ZIFs-8) via EDC-NHS chemistry. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were conducted to monitor the electrochemical characterization. With respect to unique π–π interactions between aptamer and graphene oxide (GO), the differential pulse voltammetry technique was applied with ferrocene-graphene oxide (Fc-GO) as an electroactive indicator for the detection of Pseudomonas aeruginosa (P. aeruginosa). In the presence of P. aeruginosa, the configuration of the aptamer showed a change and Fc-GO was released from the electrode surface. On the basis of the signal-off strategy, the proposed biosensor exhibits a wide linear dynamic range (from 1.2 × 10¹ to 1.2 × 10⁷ CFU mL^–1) with a low detection limit. The results reveal that the fabricated aptasensor has high potential applicability in the field of monitoring disease therapy and controlling the safety of the clinical sites.