Recent Advances in Silica-Nanomaterial-Assisted Lateral Flow Assay

Abstract

Lateral flow assays (LFAs) have attracted much attention as rapid and affordable point-of-care devices for medical diagnostics. The global SARS-CoV-2 pandemic has further highlighted the importance of LFAs. Many efforts have been made to enhance the sensitivity of LFAs. In recent years, silica nanomaterials have been used to either amplify the signal of label materials or provide stability, resulting in better detection performance. In this review, the recent progress of silica-nanomaterial-assisted LFAs is summarized. The impact of the structure of silica nanomaterials on LFA performance, the challenges and prospects in this research area are also discussed.

Keywords: lateral flow assay; point-of-care device; signal amplification; silica nanomaterials.

Figure 1

Schematic illustration of a silica-nanomaterial-assisted lateral flow assay (LFA). In LFAs, silica nanomaterials usually work as a protective shell to stabilize label materials, a carrier to enrich label materials for signal amplification or the colored label itself. Reprinted with permission from References [20,21,22,23].

Figure 3

Silica-nanomaterial-assisted fluorescent LFA. (A) LFA using silica-shell-encapsulated QDs for simultaneous detection of four mycotoxins. (B) A core–shell SiO₂-QD nanocomposite (SiO₂@PEI-QD) was developed for use as an LFA label for rapid detection of Salmonella typhimurium in milk. (C) QDs were loaded into DMSNs for signal amplification, and the impacts of DMSN size on QD–DMSN interaction and the LOD of resultant LFA were also investigated. (D) Dendritic mesoporous silica-encapsulated UCNPs for SARS-CoV-2 detection. Reprinted with permission from References [6,19,56,65].

Figure 6

Silica-nanomaterial-assisted SERS-LFA. (A) Core–shell Au/MBA@mSiO₂ nanoparticles used as SERS-LFA labels for co-detection of CRP and SAA. (B) Silica sphere immobilized dual-layer Raman reporters for anti-SARS-CoV-2 IgM/IgG detection. Reprinted with permission from References [81,84].

Figure 2

Silica-nanomaterial-assisted colorimetric LFA. (A) A silica shell was grown on AuNPs to enhance stability and avoid aggregation of label materials in order to enhance the detection sensitivity for vanillin in milk powder. (B) Multiple AuNPs were deposited onto solid silica sphere for the semiquantitative detection of prostate-specific antigens. (C) Multiple AuNPs were loaded into dendritic mesoporous silica nanoparticles for semiquantitative analysis. Reprinted with permission from References [21,34,41].

Figure 4

Dual-model LFA with both QDs (florescent) and AuNPs (colorimetric) integrated into DMSNs for early diagnosis of kidney injury. Reprinted with permission from Reference [22].

Figure 5

Silica-nanomaterial-assisted ECL-LFA. (A) [Ru(Bpy)₃]²⁺-loaded MSNs as ECL probes for sensitive and quantitative detection of troponin I. (B) MSN-based aptamer-gated indicator releasing strategy for antibiotic detection. Reprinted with permission from References [70,72].