Rolling Circle Amplification/G‐Quadruplex‐Based Dual‐Signal Ratiometric Electrochemical Aptasensor for Ultrasensitive Detection of Pathogenic Bacteria

Abstract

Accurate and efficient detection of pathogenic bacteria plays a crucial role in the diagnosis of infectious diseases. However, rapid and highly sensitive detection of specific bacteria in clinical samples remains challenging. In this study, we developed a ratiometric dual‐signal electrochemical biosensor for ultrasensitive detection of pathogenic bacteria, based on an aptamer recognition‐induced rolling circle amplification (RCA)/G‐quadruplex strategy. On the surface of a gold electrode chip, we used an aptamer sequence (P1) conjugated to ferrocene (Fc) to capture the target bacterium. This capture released a different, previously bound sequence (P2) sequence that initiated the RCA/G‐quadruplex cascade, which, in the presence of potassium ions, was able to bind the electrochemical indicator methylene blue (MB). We integrated the signals from the loss of Fc and the appearance of MB (IMB/IFC ratio) to quantify the target bacteria concentration. This biosensor showed excellent detection performance and specificity, with a detection limit of 10 CFU/mL. Notably, it showed great diagnostic potential for clinical infectious diseases caused by pathogenic bacteria in precise/personalized medicine applications.

Recent Advances in Aptamer-Based Biosensors for Bacterial Detection

“…This high sensitivity suggests the sensor's applicability in food safety and prevention. In another recent example, Ding et al [164] developed a novel ratiometric dual-signal electrochemical aptasensor for pathogenic bacteria at the single-cell level. This sensor was based on the aptamer-recognition-induced rolling circle amplification/G-quadruplex strategy [165][166][167].…”

Aptamer-Based Biosensors for Bacterial Detection

“…This high sensitivity suggests the sensor's applicability in food safety and prevention. In another recent example, Ding et al [169] developed a novel ratiometric dual-signal electrochemical aptasensor for pathogenic bacteria at the single-cell level. This sensor was based on the aptamer recognition-induced Rolling Circle Amplification/G-quadruplex strategy [170][171][172].…”