Colorimetric detection of Listeria monocytogenes using one-pot biosynthesized flower-shaped gold nanoparticles

The present study described a novel fast, simple and green one-pot synthesis approach of flower-shaped gold nanoparticles (flower-shaped AuNPs) by using antioxidant plant extracts. The AuNPs synthesized by Alchemilla mollis extract showed maximum absorbance at 610 nm and were polydispersed flower-shaped with average size (±SD) of 68.7 ± 2.8 nm. We have explored a colorimetric sensing assay for rapid detecting Listeria monocytogenes by using single-stranded DNA (ssDNA) conjugated flower-shaped AuNPs. ssDNA were used as probe for DNA detection and the synthesized flower-shaped AuNPs were used as indicators. The limit of detection for hlyA gene and genomic DNA of Listeria monocytogenes were 48.4 ng and 100.4 ng, respectively. The proposed assay is fast and specific for Listeria monocytogenes detection, with the improved color change and stability.