1 research outputs found
Gold Nanoparticle-Based Enzyme-Linked Antibody-Aptamer Sandwich Assay for Detection of <i>Salmonella</i> Typhimurium
Enzyme-linked immunosorbent assay
(ELISA) provides a convenient means for the detection of <i>Salmonella
enterica</i> serovar Typhimurium (STM), which is important for
rapid diagnosis of foodborne pathogens. However, conventional ELISA
is limited by antibody–antigen immunoreactions and suffers
from poor sensitivity and tedious sample pretreatment. Therefore,
development of novel ELISA remains challenging. Herein, we designed
a comprehensive strategy for rapid, sensitive, and quantitative detection
of STM with high specificity by gold nanoparticle-based enzyme-linked
antibody-aptamer sandwich (nano-ELAAS) method. STM was captured and
preconcentrated from samples with aptamer-modified magnetic particles,
followed by binding with detector antibodies. Then nanoprobes carrying
a large amount of reporter antibodies and horseradish peroxidase molecules
were used for colorimetric signal amplification. Under the optimized
reaction conditions, the nano-ELAAS assay had a quantitative detection
range from 1 × 10<sup>3</sup> to 1 × 10<sup>8</sup> CFU
mL<sup>–1</sup>, a limit of detection of 1 × 10<sup>3</sup> CFU mL<sup>–1</sup>, and a selectivity of >10-fold for
STM in samples containing other bacteria at higher concentration with
an assay time less than 3 h. In addition, the developed nanoprobes
were improved in terms of detection range and/or sensitivity when
compared with two commercial enzyme-labeled antibody signal reporters.
Finally, the nano-ELAAS method was demonstrated to work well in milk
samples, a common source of STM contamination