Fluorescent Ru(phen)₃²⁺-Doped Silica Nanoparticles-Based ICTS Sensor for Quantitative Detection of Enrofloxacin Residues in Chicken Meat

Abstract

A Ru(phen)3(2+)-doped silica fluorescent nanoparticle (FN)-based immunochromatographic test strip (ICTS) sensor was developed for rapid, high sensitivity, easy to use, and low cost quantitative detection of enrofloxacin (ENR) residues in chicken meat. The fluorescence signal intensity of the FNs at the test line (FI(T)) and control line (FI(C)) was determined with a prototype of a portable fluorescent strip reader. Unique properties of Ru(phen)3(2+) doped silica nanoparticles (e.g., large Stokes shift, high emission quantum yield, and long fluorescence lifetime) were combined with the advantages of ICTS and an easy to make portable fluorescent strip reader. The signal was based on FI(T)/FI(C) ratio to effectively eliminate strip to strip variation and matrix effects. Various parameters that influenced the strip were investigated and optimized. Quantitative ENR detection with the FNs ICTS sensor using 80 μL sample took only 20 min, which is faster than the commercial ELISA kit (that took 90 min). The linear range of detection in chicken extract was established at 0.025-3.500 ng/mL with a half maximal inhibitory concentration at 0.22 ± 0.02 ng/mL. Using the optimized parameters, the limit of detection (LOD) for ENR using the FNs ICTS sensor was recorded at 0.02 ng/mL in chicken extract. This corresponds to 0.12 μg/kg chicken meat which is two (2) orders of magnitude better that the maximum residue limits (MRLs) imposed in Japan (10 μg/kg) and three (3) orders of magnitude better than those imposed in China. The intra- and inter-assay coefficient of variations (CVs) were 6.04% and 12.96% at 0.5 ng/mL, 6.92% and 12.61% at 1.0 ng/mL, and 6.66% and 11.88% at 2.0 ng/mL in chicken extract, respectively. The recoveries using the new FNs ICTS sensor from fifty (50) ENR-spiked chicken samples showed a highly significant correlation (R(2) = 0.9693) with the commercial enzyme-linked immunosorbent assay (ELISA) kit. The new FNs ICTS sensor is a simple, rapid, sensitive, accurate, and inexpensive quantitative detection of ENR residues in chicken meat and extracts.

Nanoparticle-based lateral flow biosensors

“…Although the results are satisfying, QDs and UPTs exhibit better limits of detection and working ranges. Huang et al (2013) covered silica microparticles with Ru phen 3 2 ( ) + complex, which also exhibits fluorescent properties, obtaining a good limit of detection, 20 pg/mL. Edwards and Baeumner (2006) and Khreich et al (2008) used liposomes to encapsulate fluorescent dyes, getting higher sensitivity when using larger particles, with limits of detection close to 20 pg/mL.…”

Rapid and quantitative detection of 4(5)-methylimidazole in caramel colours: A novel fluorescent-based immunochromatographic assay

“…In recent years, fluorescent microspheres, instead of colloidal gold, have been developed and used in ICA format with increased sensitivity and accuracy (Majdinasab et al, 2015;Wang et al, 2014). For example, fluorescence-based ICA has been established for sulfamethazine and enrofloxacin residue detection (Chen et al, 2013;Huang et al, 2013). The fluorescence-based ICA was shown to be able to test low-molecular weight compounds with high sensitivity and high specificity.…”

Development of immunochromatographic strip test using fluorescent, micellar silica nanosensors for rapid detection of B. abortus antibodies in milk samples

“…Each silica nanoparticle can contain a large number of photochemically active species allowing bright luminescence and a high quantum yield (Ambrogio et al 2011;Folling et al 2008;Huang et al 2013;Kim et al 2013). Additionally, silica nanoparticles with fluorophores as cargo warrant a stable, robust, sensitive nanosensing system, as fluorescence is a detection methodology with a high signal to noise ratio, and easily distinguishes compounds based on a separate excitation and emission spectra.…”