Chen, Rui Huang, Xiaolin Xu, Hengyi Xiong, Yonghua Li, Yanbin Plasmonic Enzyme-Linked Immunosorbent Assay Using Nanospherical Brushes as a Catalase Container for Colorimetric Detection of Ultralow Concentrations of <i>Listeria monocytogenes</i> Plasmonic enzyme-linked immunosorbent assay (pELISA) based on catalase (CAT)-mediated gold nanoparticle growth exhibits ultrahigh sensitivity for detecting disease-related biomarkers using sandwich formats. However, the limit of detection (LOD) of this strategy for <i>Listeria monocytogenes</i> is only around 10<sup>3</sup> CFU/mL, which considerably exceeds the amount of <i>L. monocytogenes</i> commonly present in food products (<100 CFU/g). Herein, we report an improved pELISA method for detection of <i>L. monocytogenes</i> at ultralow concentrations with the sandwich formats using silica nanoparticles carrying poly­(acrylic acid) brushes as a “CAT container” to increase enzyme loading for enhancing the detection signal. Under optimal conditions, the proposed pELISA exhibits good specificity and excellent sensitivity for <i>L. monocytogenes</i> with a LOD of 8 × 10<sup>1</sup> CFU/mL in 0.01 M phosphate-buffered saline, via a reaction that can be discriminated by the naked eye. The LOD obtained by this method was 2 and 5 orders of magnitude lower than that of conventional CAT-based pELISA and horseradish peroxidase (HRP)-based conventional ELISA, respectively. Coupled with large-volume immunomagnetic separation, the LOD for <i>L. monocytogenes</i>-spiked lettuce samples reached 8 × 10<sup>1</sup> CFU/g. The improved pELISA also exhibited a great potential in detecting a single cell of <i>L. monocytogenes</i> in 100 μL of solution. nanoparticle;100 μ L;sensitivity;detection;pELISA;method;sandwich formats;HRP;Listeria;ELISA;increase enzyme loading;exhibit;LOD;CFU 2015-12-30
    https://acs.figshare.com/articles/journal_contribution/Plasmonic_Enzyme_Linked_Immunosorbent_Assay_Using_Nanospherical_Brushes_as_a_Catalase_Container_for_Colorimetric_Detection_of_Ultralow_Concentrations_of_i_Listeria_monocytogenes_i_/2093761
10.1021/acsami.5b10181.s001