Advantage of Eu³⁺‐Doped Polystyrene Microspheres Compared with Colloidal Gold Used in Immunochromatographic Assays for the Detection of Melamine in Milk

Abstract

Colloidal gold and Eu -doped fluorescent microspheres were applied as labels to develop the immunochromatographic strips for detecting melamine in milk. Under the optimized condition, the visual detection limit of colloidal gold-immunochromatographic test strip (ICTS) was 150 μg/L of melamine in phosphate-buffered saline (PBS), although the visual detection limit of fluorescent nanoparticles (FN)-ICTS was 75 μg/L in PBS. As thermal acceleration test, FN-ICTS could be stored at 37 °C for at least 11 d before sample testing, but the color of the lines on colloidal gold-ICTS faded away after 7-d storage. The visual result of FN-ICTS was more stable than that of colloidal gold-ICTS, and the fluorescence intensity of the line on FN-ICTS could be maintained up to 30 d at 22 °C after sample testing. Once the immunochromatographic strips were used to detect melamine in milk, no negative effect of milk components on the performance of FN-ICTS was identified, whereas the performance of colloidal gold-ICTS was significantly influenced by milk matrix.

Effects of low‐dose melamine exposure during pregnancy on maternal and fetal kidneys in rats

“…Although advancement of detection methods and the monitoring of food safety can help reduce the incidence of high melamine adulteration, low‐level unintentional melamine contamination of the food chain by giving food animals melamine‐laced animal feed, degradation of the pesticide cyromazine, migration from melamine‐ware and breakdown of melamine foam may still post risk of the contact of the compound. Detection of melamine in the breast milk, whole fetus, and amniotic fluid indicated the contact of melamine through the placental and the lactational transfer, that is, the melamine contact can be as early as in utero and some of the melamine is recirculating in the amniotic fluid in rats .…”

Rapid Monitoring of Vancomycin Concentration in Serum Using Europium (III) Chelate Nanoparticle-Based Lateral Flow Immunoassay

“…In recent years, by combining fluorescence-based LFIAs with portable strip readers, LFIAs can satisfy the requirement of semi-quantification detection ( Chen Z. et al, 2020 ; Kim et al, 2021 ; Wang et al, 2021 ). The application of lanthanide-doped polystyrene nanomaterials can remedy the defects of conventional fluorescent dyes, which include photobleaching, poor stability, or poor quantum yield, and the advantages of simplicity and rapidity can be retained ( Tang et al, 2017 ). Furthermore, lanthanide chelates are appropriate as immunoassay markers for trace analysis with the advantages of long fluorescence decay time, large Stoke shift between excitation light and emission light, narrow excited fluorescence band, sharp fluorescence emission, and excellent photo-stability, all of which lead to outstanding analysis sensitivity and accuracy ( Liu et al, 2021 ).…”

Comparison of the detection performance of two different one-step-combined test strips with fluorescent microspheres or colored microspheres as tracers for influenza A and B viruses

“…They are based on immunochromatographic assays and have been used widely in several fields, such as medical science, food security and so on [9, 10]. Compared to colloidal gold detection [11], the use of fluorescent microspheres for tracers is rapid, sensitive, and reliable [12–14]. Following lighting with an ordinary UV lamp or special equipment, reaction bands of the fluorescent microspheres for tracers can be observed with the naked eye.…”