Aptamer-molecularly imprinted polymer sensors for the detection of bacteria in water

Bacteria pose a significant threat to human health as they can cause diseases and outbreaks; therefore rapid, easy, and specific detection of bacteria in a short time is crucial. Various methods such as polymerase chain reaction and enzyme-linked immunosorbent assay have been developed for bacteria detection. However, most of these methods require sample preparation, trained personnel, and 2-4 days for identification. In this study, an electrochemical sensor has been developed in which a molecularly imprinted polymer (MIP) and aptamer were used together as a bioreceptor for the multiplexed detection of Staphylococcus aureus and Escherichia coli. Non-Faradaic electrochemical impedance spectroscopy (EIS) was employed to assess bacterial detection. Sensor performance was assessed in buffer solution, deionized water and spiked tap water. Aptamer-molecularly imprinted polymer (Apta-MIP) based electrochemical sensors demonstrate high sensitivity and selectivity for the detection of S. aureus and E. coli, with limits of detection of 4 CFU/mL and 2 CFU/mL, respectively. Additionally, these sensors exhibited a broad dynamic range from 1 CFU/mL to 10⁸ CFU/mL. The Apta-MIPs performance surpasses those obtained for Aptasensors alone and MIPs alone, demonstrating the high efficiency of the double recognition effect that originates from the affinity between aptamer and bacteria and target-specific cavities on the polymer. This is the first study in which aptamers and imprinted polymers were used as a hybrid bioreceptors for multiplexed detection of bacteria. The Apta-MIP sensors produced in this study can be used as a point-of-care diagnostic tool for bacteria-related diseases and test of water quality.