Enhancing the Sensitivity of Lateral Flow Immunoassay by Magnetic Enrichment Using Multifunctional Nanocomposite Probes

Abstract

For lateral flow immunoassay (LFIA), it is an important challenge to enhance the detection sensitivity to the same level as polymerase chain reaction or enzyme-linked immunosorbent assay to make LFIA pervasive in the field of on-site environmental analysis. We recently demonstrated that the LFIA sensitivity is dramatically enhanced by using Pt-nanoparticle−latex nanocomposite beads (Pt-P2VPs) as probes for the detection of the influenza A (H1N1) antigen compared with using conventional Au colloids as probes. Here, to further enhance the LFIA sensitivity using Pt-P2VPs, superparamagnetic iron oxide nanoparticles (SPIONs) were chemically conjugated to Pt-P2VPs (Pt-P2VP@SPION) to give them magnetic separation capability (enrichment and/or purification). To investigate the effect of magnetic enrichment on the LFIA sensitivity in a sandwich format, the C-reactive protein (CRP) was chosen as a model analyte and anti-CRP antibody (CRPAb)-conjugated Pt-P2VP@SPION (Pt-P2VP@SPION-CRPAb) beads were used as probes. The visual limit of detection (LOD) of LFIA was successfully lowered by increasing the magnetic enrichment factor φ. The minimum LOD under the present experimental conditions was 0.08 ng/mL for φ = 40, which is 26-fold lower than that of the standard Au-nanoparticle-based LFIA. In theory, the LOD can be unlimitedly decreased by just increasing φ. However, the times required for both the antigen−antibody binding reaction and magnetic separation dramatically increase with φ. We also propose solutions to overcome this drawback.

Toward Next Generation Lateral Flow Assays: Integration of Nanomaterials

“…(A, ii, a) TEM image, (b) HAADF-STEM image, and (c–f) EDS elemental mapping images of Pt–P2VP@SPION. Reprinted (adapted) with permission from ref . Copyright 2021 American Chemical Society.…”

“…The former has been applied by Ren et al, 73 who have used antibody-functionalized magnetic particles in order to concentrate valosin containing protein up to 10-fold, yielding a 4000-times greater sensitivity than the conventional LFA. 73 Similarly, Son Le et al 74 have used superparamagnetic iron oxide nanoparticles (SPIONs) that provide a magnetic enrichment factor (φ) = 40, for the detection of C-reactive protein. This enables a 26-fold lower LoD (0.08 ng mL −1 ) compared to the conventional AuNPbased LFA (Figure 4A).…”

“…This enables a 26-fold lower LoD (0.08 ng mL −1 ) compared to the conventional AuNPbased LFA (Figure 4A). 74 Magnetic enrichment strategies have shown great performance in the lab over the past decade; however, their commercialization has been hindered by the fact that they usually require multiple washing steps that make the assay less user-friendly and more prone to error.…”

Utilizing Heterostructured Porous Particles to Improve Traditional Paper Chromatography for Spontaneous Protein Separation

“…Spacing between fibers is large enough to propel the self-flow of the liquid, in high contrast with classical column chromatography (Figure ). On the basis of liquid self-transport, lateral flow strips and paper-based microfluidics − for sensitive protein, − DNA, , and RNA − detection have been fabricated, which shows great potential in resource-poor areas. Moreover, paper chromatography has been used to separate organics − and inorganic metal ions , since Martin used two-dimensional paper chromatography to complete the qualitative analysis of proteins. − It might be promising in self-driven protein separation.…”

Characterization of FcγRIa (CD64) as a Ligand Molecule for Site-Specific IgG1 Capture: A Side-By-Side Comparison with Protein A

“…Various techniques (fluorescence, optic, electrochemical) are available for IgG detection and enhanced their sensitivity by applying surface modification and nanoparticle conjugation (gold, magnetic, quantum dots, etc. ). ,,− An optic-based approach, surface plasmon resonance, offers many advantages such as real-time monitoring, low sample consumption, and reduced assay time . Analytical characterization of the FcγRIa as an alternative ligand molecule for site-directed IgG1 capture was performed in the current study.…”