Universal and Ultrasensitive Immunochromatographic Assay by Using an Antigen as a Bifunctional Element and Antialbumin Antibody on a Test Line

Abstract

A universal and ultrasensitive immunochromatographic assay (ICA) was established using antigen as a bifunctional element and antialbumin antibody in a test line. Preincubation was introduced for competitive recognition. After optimization, the linear detection of aflatoxin M1 (AFM1) with quantum dot bead (QB)-based ICA (QB-ICA) sensor ranged from 10 to 52 pg mL–1, with a 50% inhibitory concentration (IC50) of 23 pg mL–1, which was nearly 49.6-fold lower than those of ICA on a traditional structure with traditional pretreatment (IC50 = 1.10 ng mL–1) and 10-fold lower than those of ICA on a traditional structure with acid aid pretreatment (IC50 = 0.25 ng mL–1). The limit of detection (LOD) for AFM1 was 16 pg mL–1 in milk, which was approximately 16.3-fold times higher than those of ICA on a traditional structure with traditional pretreatment and 6.3-fold higher than those of ICA on a traditional structure with acid aid pretreatment. The LOD improved by 20-fold by using the proposed structure compared to that of conventional enzyme-linked immunosorbent assay (ELISA) for AFM1-spiked milk samples (IC10 = 0.12 ng mL–1). The performance and practicability of the established QB-ICA sensor were validated with a commercial ELISA kit. To evaluate universality, we successfully detected chloramphenicol, with IC50 of 0.42 ng mL–1. Given its high sensitivity and universality, the proposed QB-ICA can be used as an alternative for rapid, sensitive, and universal quantitative detection of all small-molecule analytes.

Immunochromatographic Assay Based on Polydopamine-Decorated Iridium Oxide Nanoparticles for the Rapid Detection of Salbutamol in Food Samples

“…Then, the optical intensity of the T-line was scanned with strip reader after reaction for 15 min. In this work, the limit of detection (LOD) was determined as the corresponding SAL concentration that caused a 10% inhibition of the T-line intensity by the IrO 2 @PDA-ICA, it was calculated using the following four-parameter logarithmic equation: where A 1 and A 2 are the asymptotic maximum (i.e., the T-line intensity in the absence of target analytes) and asymptotic minimum respectively, x 0 is equal to 50% inhibitory concentration (IC 50 ), and p is the curve slope at IC 50 .…”

“…Then, the optical intensity of the T-line was scanned with strip reader after reaction for 15 min. In this work, the limit of detection (LOD) was determined as the corresponding SAL concentration that caused a 10% inhibition of the T-line intensity by the IrO 2 @PDA-ICA, it was calculated using the following four-parameter logarithmic equation: 31…”

Lateral flow assays for viruses diagnosis: Up-to-date technology and future prospects

“…Quantum dots (QD) have become popular as fluorescent tags in the LFA system because of their excellent optical features such as wide excitation, quantifiable fluorescence intensity, and great stability. Many QD-based LFAs have been developed to accomplish high-level detection [ [66] , [67] , [68] ]. According to a recent study, some blood samples from COVID-19 patients cross-reacted to the SARS-CoV NP protein.…”

Recent Advances in Novel Lateral Flow Technologies for Detection of COVID-19

“…Many QD-based LFIAs have been developed to achieve ultrasensitive detection [ 62 , 103 , 104 , 105 ]. In a recent study, Wang et al reported a dual-mode LFIA for SARS-CoV-2 IgM/IgG detection based on QD nanobeads ( Figure 7 ) [ 63 ].…”