Development of quantum dot‐based fluorescence lateral flow immunoassay strip for rapid and quantitative detection of serum interleukin‐6

Abstract

Background Interleukin‐6 (IL‐6) is an inflammatory factor that increases rapidly in response to infectious diseases including sepsis. The aim of this study is to develop a quantum dot (QD)‐based fluorescence lateral flow immunoassay (LFIA) strip that can rapidly and accurately detect IL‐6 levels. Methods QD‐based LFIA strips were fabricated by conjugating CdSe/ZnS QDs to the IL‐6 antibody. Performance verification and clinical sample analysis were carried out to evaluate the newly developed strip. Results QD‐based LFIA strips were successfully fabricated. The test strip's linear range was 10–4000 pg/ml, with a linear correlation coefficient of R2 ≥ .959. The sensitivity of the test strip was 1.995 pg/ml. The recovery rate was 95.72%–102.63%, indicating satisfying accuracy. The coefficient of variation (CV) of the intra‐assay was 2.148%–3.903%, while the inter‐assay was 2.412%–5.293%, verifying the strip's high precision. The cross‐reaction rates with various interleukins (IL‐1α, IL‐1β, IL‐2, IL‐4, and IL‐8) and interferon‐γ (IFN‐γ) were all <0.1%. When the strip was placed in a 50°C oven for 1, 2, 3, and 4 weeks, the test results were not significantly altered compared to storage at room temperature. Furthermore, 200 clinical serum samples were analyzed to compare the strip with the Beckman chemiluminescence immunoassay (CLIA) kit, which revealed a high correlation (n = 200, R2 = .9971) for the detection of IL‐6. Conclusions The QD‐based test strip can rapidly and quantitatively detect IL‐6 levels, thus meeting the requirement of point‐of‐care test (POCT) and showing excellent clinical prospects.

Ultrasensitive lateral-flow assays via plasmonically active antibody-conjugated fluorescent nanoparticles

“…2d) enabled the detection down to 93 fg ml −1 (Fig. 2e, five-parameter logistic fit), which represents a 1,785-fold improvement in the LOD compared with conventional AuNP-based LFAs and at least an order of magnitude higher than the previously reported LFAs [43][44][45][46] . The LOQ of fluorometric p-LFA (298 fg ml −1 ) is 2,288-fold better than the LOQ of colorimetric LFA (682 pg ml −1 ).…”

Self-Assembling Antibody Network Simplified Competitive Multiplex Lateral Flow Immunoassay for Point-of-Care Tests

“…The coefficients of variation (CVs) at each concentration were below 15%. 39 Compared to mCNAN-mLFIA, the CV of intra-assay precision was decreased by 3.45% for the Tc line and 5.39% for the Ts line (Figure 4A,B), while the CV of the interassay precision was decreased by 8.29% for the Tc line and 13.19% for the Ts line for CNAN-mLFIA (Figure 4C,D). The CV of CNAN-mLFIA was <15% in all cases, indicating that higher precision can be obtained for CNAN-mLFIA.…”

“…The interassay precision was determined on 10 consecutive days with two replicates. The coefficients of variation (CVs) at each concentration were below 15% . Compared to mCNAN-mLFIA, the CV of intra-assay precision was decreased by 3.45% for the Tc line and 5.39% for the Ts line (Figure A,B), while the CV of the interassay precision was decreased by 8.29% for the Tc line and 13.19% for the Ts line for CNAN-mLFIA (Figure C,D).…”

Optical Nanobiosensor-Based Point-of-Care Testing for Cardiovascular Disease Biomarkers

“…In another work, Luo et al also fabricated an IL-6 antibody immobilized CdSe/ZnS QDs-based fluorescence lateral flow immunoassay (LFIA) strip for selective detection of IL-6 in human serum. 187 Recently, Wu et al successfully demonstrated a new approach using fluorescent titanium nanoclusters (Ti NCs) for highly selective sensitive detection of CK-MM in myocardial infarction. 188 The sensing phenomenon of Ti NCs is the strong binding nature with the phosphate group of ATPS, in which the creatine was converted into phosphocreatine as shown in Figure 7c.…”