Highly Sensitive Colorimetric Detection of Listeria monocytogenes by Using Gold Nanoparticles Based on Magnetic Metal-Organic Framework Separation

Abstract

In this study, magnetic metal organic framework composites as capture probe and immunofunctionalized gold nanoparticles as signal probe were used to develop a rapid colorimetric method for the detection of Listeria monocytogenes. Under optimal conditions, the visual detection limit for L. monocytogenes was 1.2 × 103 CFU/mL. The results of ultraviolet spectroscopy showed a good linear relationship in the range of 1.2 × 101‒1.2 × 108 CFU/mL (Y = 0.519 ‒ 0.043X, R2 = 0.978), the detection limit was as low as 0.45 CFU/mL, and the intra-batch coefficient of variation of all concentration gradients was between 0.31% and 1.30%. The recoveries for spiked chicken breast were 91.1%‒108.7% with coefficient of variation less than 7.4%, and the result was consistent with that of the plate counting method. In conclusion, the proposed assay is rapid, accurate sensitive, and highly applicable to the detection of foodborne pathogens.

Keywords

• listeria monocytogenes; gold nanoparticles; colorimetric assay; magnetic separation