Rapid, Quantitative, High-Sensitive Detection of Escherichia coli O157:H7 by Gold-Shell Silica-Core Nanospheres-Based Surface-Enhanced Raman Scattering Lateral Flow Immunoassay

Abstract

Escherichia coli O157:H7 is regarded as one of the most harmful pathogenic microorganisms related to foodborne diseases. This paper proposes a rapiddetection biosensor for the sensitive and quantitative analysis of E. coli O157:H7 in biological samples by surface-enhanced Raman scattering (SERS)-based lateral flow immunoassay (LFIA). A novel gold-shell silica-core (SiO 2 /Au) nanosphere (NP) with monodispersity, good stability, and excellent SERS activity was utilized to prepare highperformance tags for the SERS-based LFIA system. The SiO 2 /Au SERS tags, which were modified with two layers of Raman reporter molecules and monoclonal antibodies, effectively bind with E. coli O157:H7 and form sandwich immune complexes on the test lines. E. coli O157:H7 was quantitatively detected easily by detecting the Raman intensity of the test lines. Under optimal conditions, the limit of detection (LOD) of the SiO 2 /Au-based SERS-LIFA strips for the target bacteria was 50 cells/mL in PBS solution, indicating these strips are 2,000 times more sensitive than colloidal Au-based LFIA strips. Moreover, the proposed assay demonstrated high applicability in E. coli O157:H7 detection in biological samples, including tap water, milk, human urine, lettuce extract and beef, with a low LOD of 100 cells/mL. Results indicate that the proposed SERS-based LFIA strip is applicable for the sensitive and quantitative determination of E. coli O157:H7.

Point-of-care diagnostics for infectious diseases: From methods to devices

“…The SiO 2 /Au SERS tags were then modified with two layers of Raman reporter molecules and monoclonal antibodies for specifically and effectively binding with E. coli O157:H7 and forming sandwich immune complexes on the test lines. Under optimal conditions, this biosensor showed a detection limit of 50 cells mL −1 in PBS solution and 100 cells mL −1 in real samples, which are 2000 times more sensitive than colloidal Au-based lateral flow immunoassay strips [187] . Most recently, Lee et al developed a PCR-coupled paper-based SERS biosensor composed of silver-nanowires (AgNWs) for rapid and sensitive determination of Mycoplasma pneumoniae DNA at the POC ( Fig.…”

“…Moreover, the whole process of the biosensor could be completed within 50 min and exhibited recoveries from 95.0% to 106.4% with relative standard derivation less than 5.3% in real samples [186] . Shi et al designed a rapid SERS-based lateral flow immunoassay biosensor for the sensitive and quantitative POC detection of Escherichia coli ( E. coli ) O157:H7 in biological samples [187] . Firstly, novel gold-shell silica-core nanospheres (SiO 2 /Au) with monodispersity, good stability, and excellent SERS activity were prepared and utilized as high performance tags.…”

Rapid field determination of SARS-CoV-2 by a colorimetric and fluorescent dual-functional lateral flow immunoassay biosensor

“…Various composite nanoparticles have been explored as signal markers to overcome the drawbacks of Au-based LFIA and improve detection performance. Such markers include fluorescent microspheres, carbon-based nanoparticles (NPs), surface-enhanced Raman scattering (SERS) nanomaterials, up-converting phosphors, and many others [15] , [16] , [17] , [18] , [19] . As a new type of fluorescent materials, quantum dots (QDs) have been applied to LFIA systems.…”

“…Nonetheless, the clinical application of QD-based LFIA has limitations owing to the small particle size of QDs (5-20 nm) and their poor biocompatibility [17] . Thus, QDs are assembled on carrier materials (such as Fe 3 O 4 , polymer, SiO 2 , and latex) to prepare QD beads (QBs) [15] , [18] , [19] , [20] , [21] . Compared with QD-based LFIA, QB-based LFIA can produce a higher fluorescence signal and sensitivity [17] , [22] , [23] .…”

Lateral Flow Immunoassay of SARS-CoV-2 Antigen with SERS-Based Registration: Development and Comparison with Traditional Immunoassays

“…The effectiveness of the implementation of SERS nanotags in LFIA tests for the detection of various analytes was evaluated in a review by Khlebtsov et al [ 15 ]. The SERS-based LFIAs were successfully applied for quantitative detection of antibiotics [ 19 ], biomarkers [ 20 , 21 , 22 , 23 ], allergens [ 24 ], pathogens [ 25 , 26 ], and so on. To date, only a few researchers have proposed the integration of SERS nanotags with LFIA to improve the efficiency of COVID-19 diagnostics through serological IgM and IgG testing [ 18 , 27 ], whereas in the case of SARS-CoV-2 antigen detection, the SERS technique was not earlier applied.…”