Dual Aptamer-Copper (II) Phosphate Nanocomposite-Based Point-of-Care Biosensor for the Determination of Escherichia coli O157:H7 through Pressure Monitoring with a Hand-Held Barometer

Abstract

Here, two types of aptamer (specific to E. coli O157:H7 pathogenic bacteria) Cu₃(PO₄)₂ nanocomposites loaded with Fe₃O₄ nanoparticles (aptamer@Fe₃O₄, magnetic separation) and platinum nanoparticles (PtNPs) (aptamer@PtNP) were prepared in house via enzymatic hydrolysis of H₂O₂ to O₂ through a one-step method. In the proposed point-of-care biosensor, these nanocomposites were used as capture and signal probes for the determination of pathogenic E. coli O157:H7 bacteria via hand-held barometers detecting gas pressure signals in a sealed bottle. The pressure signal was linear when the concentration of E. coli O157:H7 was from 10³ to 10⁸ CFU/mL. With the easily prepared dual aptamer-Cu₃(PO₄)₂ nanocomposites and the hand-held barometer signal readout, the proposed point-of-care biosensor was shown to be a potential tool for the determination of pathogenic bacteria in underdeveloped areas.

Keywords:

• Aptamer
• copper (II) phosphate
• Escherichia coli O157:H7
• hand-held barometer
• nanocomposites
• point-of-care biosensor

Disclosure statement

The authors declare that there are no conflicts of interest.

Additional information

Funding

This work was financially supported by the National Key Research and Development Program of China (Grant Number 2016YFD0501000).