Dual-Signal Readout Nanospheres for Rapid Point-of-Care Detection of Ebola Virus Glycoprotein

Abstract

Rapid detection of highly contagious pathogens is the key to increasing the probability of survival and reducing infection rates. We developed a sensitive and quantitative lateral flow assay for detection of Ebola virus (EBOV) glycoprotein with a novel multifunctional nanosphere (RNs@Au) as a reporter. Each RNs@Au contains hundreds of quantum dots and dozens of Au nanoparticles and can achieve enhanced dual-signal readout (fluorescence signal for quantitative detection and colorimetric signal for visual detection). Antibody (Ab) and streptavidin (SA) were simultaneously modified onto the RNs@Au to label the target and act as signal enhancer. After the target was labeled by the Ab-RNs@Au-SA and captured on the test line, biotin-modified RNs@Au was used to amplify the dual signal by the reaction of SA with biotin. The assay enables naked-eye detection of 2 ng/mL glycoprotein within 20 min, and the quantitative detection limit is 0.18 ng/mL. Additionally, the assay has been successfully tested in field work for detecting EBOV in spiked urine, plasma, and tap water samples and is thus a promising candidate for early diagnosis of suspect infections in EBOV-stricken areas.

Development of a SERS-based lateral flow immunoassay for rapid and ultra-sensitive detection of anti-SARS-CoV-2 IgM/IgG in clinical samples

“…The corresponding calibration curve was plotted by S protein antibody concentration and is shown in Fig. 3 C. The limit of detection (LOD) of the SERS results was 1 pg/mL, which was calculated via the IUPAC standard method (LOD = Y blank + 3SD, where Y blank represents the average SERS signal of the blank control and 3SD represent three times the standard deviation of the blank control) [ 35 , 36 ]. By comparison, the LOD of the SERS-LFIA strips based on the SERS signal was 1000 times more sensitive than that obtained from the SiO 2 @Ag aggregation-based visualization result.…”

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

“…Error bars showed the standard deviation (SD) of five detections. The LOD of E. coli O157:H7 analyzed using the LFIA strips was 50 cells/mL based on the IUPAC formula (LOD = y blank + 3 × SD blank , where y blank and SD blank are the average Raman intensity and the SD of the blank control, respectively) (Hu et al, 2017;Putnin et al, 2019). The SiO 2 /Au-based SERS-LFIA strips were characterized by SEM to prove that the SERS signal came from the SERS tags fixed on the test line.…”

Lateral Flow Immunoassay for Naked Eye Detection of Mycobacterium tuberculosis

“…Incorporation of nanoparticles (NPs), such as gold nanoparticles (AuNPs) with different biorecognition elements (antibodies, peptide arrays, polymers, and aptamers), provides an effective strategy to enhance the performance of the detection systems. The AuNP-based paper biosensor initiated intensive studies recently for the diagnosis of various infectious diseases, such as malaria [14], hepatitis B virus (HBV) [15], dengue [16], Ebola virus (EBOV) [17], and other viruses [18,19]. In this context, three types of paper-based immunoassays have been demonstrated, including colorimetric-based, fluorescence-based, and electrochemicalbased immunoassays.…”