A Universal Bacterial Catcher Au–PMBA-Nanocrab-Based Lateral Flow Immunoassay for Rapid Pathogens Detection

Abstract

In traditional lateral flow immunoassays (LFIA) for pathogens detection, capture antibody (CA) is necessary and usually conjugated to Au nanoparticles (NPs) in order to label the target analyte. However, the acquisition process of the Au–CA nanoprobe is relatively complicated and costly, which will limit the application of LFIA. Herein, p-mercaptophenylboronic acid-modified Au NPs (namely Au–PMBA nanocrabs), were synthesized and applied for a new CA-independent LFIA method. The stable Au–PMBA nanocrabs showed outstanding capability to capture both Gram-negative bacteria and Gram-positive bacteria through covalent bonding. The acquired Au–PMBA–bacteria complexes were dropped onto the strip, and then captured by the detection antibody on the test line (T-line). Take Escherichia coli O157:H7 as an example, the gray value of T-line was proportional to the bacteria concentration and the linear range was 103–107 cfu·mL–1. This CA-independent strategy exhibited higher sensitivity than the traditional CA-dependent double antibody sandwich method, because detection limit of the former one was 103 cfu·mL–1 only by visual observation, which was reduced by 3 orders of magnitude. Besides, this platform successfully screened E. coli O157:H7 in four food samples with recoveries ranging from 90.25% to 107.25%. This CA-independent LFIA showed great advantages and satisfactory potential for rapid foodborne pathogens detection in real samples.

Boronate-Affinity Cross-Linking-Based Ratiometric Electrochemical Detection of Glycoconjugates

“…In aqueous media, the PBA groups exist in two forms: the negatively charged tetrahedral form (PhB­(OH) 3 − ) and the neutral trigonal planar form (PhB­(OH) 2 ) . In aqueous basic media, the addition of a hydroxyl ion (OH – ) to the trigonal planar form (sp 2 -hybridized) yields the tetrahedral form (sp 3 -hybridized). , Although both of them can react with cis -diols to form the cyclic boronate esters, the reaction of the tetrahedral form with cis -diols is much easier. , Moreover, in aqueous media, the resulting tetrahedral anions are much more stable than the trigonal planar esters . The covalent B–O bond is stable; however, the formation of the boronate esters is pH-dependent .…”

“…1 In aqueous basic media, the addition of a hydroxyl ion (OH − ) to the trigonal planar form (sp 2 -hybridized) yields the tetrahedral form (sp 3hybridized). 1,49 Although both of them can react with cisdiols to form the cyclic boronate esters, 2 the reaction of the tetrahedral form with cis-diols is much easier. 1,2 Moreover, in aqueous media, the resulting tetrahedral anions are much more stable than the trigonal planar esters.…”

Metabolism-Triggered Colorimetric Sensor Array for Fingerprinting and Antibiotic Susceptibility Testing of Bacteria

“…To further confirm the presence of d -AA on AuNPs, we synthesized AuNPs using the same method except replacing the d -AA with sodium citrate. With the absence of d -AA, the as-prepared AuNPs exhibit typical FT-IR spectra of sodium citrate-protected AuNPs (c-AuNPs), showing none characteristic peaks of d -AA (Figure S5). All these results suggest that the d -AA have been successfully wrapped on the surface of AuNPs.…”

Current Scenario of Pathogen Detection Techniques in Agro-Food Sector

“…A microfluidics-based on-chip artificial pore has been reported to sense the bacterial pathogens [ 124 ]. The on-site detection of pathogens using POC devices mostly comprise lateral flow tests and lateral flow assays [ 125 , 126 ]. Further, the integration of sensing modalities with smartphones has been easily implemented in pathogen detection [ 127 , 128 ].…”