Urease-induced metallization of gold nanorods for the sensitive detection of Salmonella enterica Choleraesuis through colorimetric ELISA

Abstract

We applied urease-induced silver metallization on the surface of gold nanorods (AuNR) to improve colorimetric ELISA for the rapid and sensitive detection of Salmonella enterica Choleraesuis. To this end, we introduced a biotin-streptavidin system as a bridge to determine the correlation between urease and S. enterica Choleraesuis concentrations. The captured urease can catalyze the hydrolysis of urea into carbon dioxide and ammonia, and the generated ammonia can then induce the deposition of silver shell on the surface of AuNR in the presence of silver nitrate and glucose. With the decreased aspect ratio (length divided by width) of AuNR, a multicolor change of AuNR solution and a significant blue shift in the longitudinal localized surface plasmon resonance absorption peak (∆λ max) of AuNR were obtained at the target concentrations of 1.21 × 10 1 to 1.21 × 10 8 cfu/mL. Consequently, the detection limits of our proposed colorimetric ELISA were as low as 1.21 × 10 2 cfu/mL for qualitative detection with naked eyes, and 1.21 × 10 1 cfu/mL for quantitative detection, in which changes in ∆λ max of AuNR were recorded with a microplate reader. These values were at least 2 to 3 orders of magnitude lower than those obtained with conventional horseradish peroxidase-based ELISA. The analytical performance of our developed colorimetric ELISA in terms of selectivity, accuracy, reliability, and practicability were investigated by analyzing S. enterica Choleraesuis-spiked pasteurized whole milk samples.

Clinical Applications of Visual Plasmonic Colorimetric Sensing

“…A colorimetric ELISA was improved to enable the detection of Salmonella enterica Choleraesuis using urease-induced silver metallization on the surface of gold nanorods (AuNR) [79]. To produce the LSPR change, this strategy involved enzyme-mediated AuNP metallization and silver deposition on nanoparticle surfaces combined with ELISA format.…”

A novel electrochemical immunosensor based on Fe3O4@graphene nanocomposite modified glassy carbon electrode for rapid detection of Salmonella in milk

“…Therefore, the combination of Fe 3 O 4 and graphene can overcome the inherent limitations of metal oxides and provide a platform for the detection of Salmonella. As noble metal nanomaterials, gold (Au), palladium (Pd), silver (Ag), and so on are widely used in biosensors due to their excellent conductivity, biocompatibility, and catalytic activity (Solanki et al, 2011;Gao et al, 2019a). Existing studies have shown that gold nanoparticles (AuNPs) can form strong Au-NH 2 bonds with amino groups on antibody (Ab; Haji-Hashemi et al, 2018;Fan et al, 2019).…”

A Sandwich‐type Electrochemical Immunosensor for the Sensitive Determination of Salmonella Typhimurium in Food

“…However, this approach is labor-intensive that required qualified personnel to take 3-5 days for a positive result. Other approaches, for instance, enzyme-linked immunosorbent assays (ELISA) [7,8] and polymerase chain reactions (PCR) [9,10], not only require complex nucleic acid extraction procedure (PCR) but also need specialized instrumentation and highly trained personnel [11][12][13]. Therefore, a rapid and simple approach is highly needed for the detection of Salmonella.…”