Impedimetric Detection of Bacteria Using Hierarchical 3D Nanostructured Gold

摘要

Impedimetric electrochemical sensing offers direct, label-free, cost-effective, accurate, and rapid detection of biological analytes. Among different types of nanostructured platforms, hierarchical structures of gold have proven to be beneficial for impedimetric and direct diagnosis of bacteria. In this research, a two-step electrodeposition method was used to achieve hierarchical nanostructures of gold for impedimetric distinction of E. coli-k12. The current observations demonstrate that the two-step electrodeposition method can convert sharp and needle-shaped structures of gold into curved and smooth structures that are able to detect bacteria, with enhanced sensitivity. The results of Electrochemical impedance spectroscopy (EIS) showed a limit of detection of approximately 90 CFU in 30 µl of solution and a linear range of detection between 3×10³and 3×10⁷CFU mL-1 for the final sensor. In addition, this structure can detect bacteria in less than 10 minutes. Ultimately, this ultrasensitive label-free bacteria sensor, based on a novel engineered hybrid method, opens interesting avenues in bacteria sensing with exciting detection abilities. Keywords: E. coli bacteria, electrodeposition, hierarchical nanostructures of gold, electrochemical impedance spectroscopy (EIS).