A signal amplification system on a lateral flow immunoassay detecting for hepatitis e‐antigen in human blood samples

Abstract

Hepatitis B e-antigen (HBeAg) is the secretory form of the nucleocapsid of the hepatitis B virus (HBV), which is a marker of viral replication. In this study, a novel signal amplification system (SAS) based on the lateral flow immunoassay (LFIA) was used for rapid detection of HBeAg in blood samples from patients or blood donors. In this assay, the detection antibody was conjugated with gold nanoparticles (GNPs), and the capture antibody was labeled with biotin. The presence of targeting antigen HBeAg in blood sample would act as a bridge with biotinylated captured antibody and GNP-conjugated detection antibody to form the dendritic nanoparticle complex. The dendritic complexes in the sample solution were migrated and immobilized on the testing line of strip coated with antibiotin antibodies. Signal intensity was massively amplified by the SAS, which was positively correlated with the concentration of targeting antigen in the blood sample and was assessed by eyes or strip scanner. The SAS worked only when targeting antigens were present in the sample. By using this SAS-LFIA, we were able to detect a very low concentration of HBeAg (9 ng/mL), which was 27-fold sensitive than that by conventional LFIA (cLFIA). A number of 420 blood samples were detested by this novel SAS-LFIA, the results were in accordance with those of enzymelinked immunosorbent assay (ELISA) completely, while the cLFIA missed an HBeAgpositive sample. In conclusion, the novel SAS has high specificity and sensitivity, which can be used to replace the conventional rapid test and ELISA in clinical diagnosis. K E Y W O R D S detection, hepatitis B e-antigen, lateral flow immunoassay, sensitivity and specificity, signal amplification system

Point-of-Care Testing for Hepatitis Viruses: A Growing Need

“…Rapid tests for the detection of HBeAg are available, but they generally have poor sensitivities ranging from 29.8% to 82%, making them impractical for accurately assessing the stage of chronic HBV infection or evaluating the risk of mother-to-child transmission at the POC [96][97][98][99]. However, a recently reported LFT using nanoparticle complexes to amplify the test-line signal exhibited high sensitivity and specificity for the detection of HBeAg [100]. Rapid tests for antibody markers that are related to HBV infection have also met with limited success.…”

Lateral Flow Assay for Hepatitis B Detection: A Review of Current and New Assays

“…The formation of dendritic nanoparticle complexes relies on biotinylated-captured monoclonal antibodies, targeting antigen molecules and nanoparticle-labeled detection monoclonal antibodies, which work only in the presence of targeting antigen in the sample solution. The signal amplification based on dendritic nanoparticles conjugated with the LFA system to detect HBeAg was developed by Si et al [ 107 ] and tested against 420 clinical samples (30 serum samples of HBsAg and HBeAg positive, 99 plasma samples of HBsAg and HBeAg positive, and 291 plasma samples of HBsAg negative). The LFA was able to detect HBeAg as low as 9 ng/mL, which was 27-fold sensitive compared with conventional LFA.…”

Study of Gold Nanoparticles Conjugated with SARS-CoV-2 S1 Spike Protein Fragments

“…We detected a shift in the peak maximum of the absorption spectrum, as can be seen in Figure 6, from 532 nm for the AuNP suspension to 540 nm for the AuNPs conjugated with SARS-CoV-2 spike protein fragments. The characteristic peak shift to higher wavelengths is indicative of the successful conjugation [41]. The lower peak intensity of the unconjugated AuNPs and conjugated AuNPs was due to losses of unconjugated AuNPs during the centrifugation and purification steps.…”