Development of ELISA-Like Fluorescence Assay for Melamine Detection Based on Magnetic Dummy Molecularly Imprinted Polymers

Abstract

We present a directly competitive fluorescence assay for highly sensitive detection of melamine in milk using magnetic dummy molecularly imprinted polymers (MDMIPs). The detection principle is based on competitive binding between the fluorescent label and melamine on the MDMIPs. The fluorescent label was obtained by combining fluorescein isothiocyanate (FITC) with melamine in ethanol and water. MDMIPs were prepared on the surface of Fe 3 O 4 @SiO 2 nanoparticles using 2,4-diamino-6-methyl-1,3,5-triazine as dummy template. The MDMIPs were characterized and their adsorption capacity was evaluated based on their static adsorption and Scatchard analysis. Results suggest that MDMIPs were successfully coated on the Fe 3 O 4 @SiO 2 surface and had a core-shell structure. Adsorption experiments suggested that the MDMIPs had higher specific recognition capacities for melamine and FITC-melamine (FITC-Mel) than did magnetic dummy molecularly non-imprinted polymers. Competitive binding between FITC-Mel and melamine was performed under the optimum conditions to determine melamine quantitatively. The linear range of this fluorescence assay was 0.1-20 mg/L for melamine detection. The detection limit was 0.05 mg/L in negative milk samples. The assay was also successfully employed to detect melamine in spiked milk samples, with satisfactory recoveries, i.e., between 70.2% and 92.7%.

Recent Advances and Future Trends in the Detection of Contaminants by Molecularly Imprinted Polymers in Food Samples

“…Recent studies have shown that MIP-based sensors successfully combine the advantages of MIP receptors and various sensing platforms, and have great potential for application in food detection. MIPs devices based on their signal transduction principles include optical (Liu G. et al, 2018), electrochemical (Ai et al, 2018), and biosensing technologies (Zhang et al, 2018). The comparison of different detection methods for chemical pollutants based on MIPs-Sensor is given in Table 2.…”

Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis

“…Fluorescence sensors for melamine in milk and infant milk powder were established by detecting the fluorescence intensity of FITC-Mel in the respective solutions. The linear range is 0.1–20.0 mg/Kg and the detection limit is 0.05 mg/Kg [59].…”

A biomimetic enzyme-linked immunosorbent assay (BELISA) for the analysis of gonadorelin by using molecularly imprinted polymer-coated microplates

“…In this context, several efforts have been already devoted to discovering new signal reporters to increase ELISA sensitivity [3] and to pinpoint capturing agents, i.e., mimetics [8], able to flank and/or supplant antibodies that generally are expensive and sensitive to environmental conditions. Looking at mimetic capturing agents, the literature has highlighted aptamers and molecularly imprinted polymers (MIPs) as the most promising ones to develop diagnostic "antibody-free" ELISA-like format assays, i.e., enzymelinked oligonucleotide assay (ELONA) [6,9], biomimetic enzyme-linked immunoassay (BELISA) [10][11][12][13][14][15][16][17][18][19], pseudo-ELISA [7,[20][21][22][23], or nanoparticle-based assay (MINA) [1,15,[24][25][26][27][28][29]. At present, a positive imbalance of the literature is in favor of aptamers, with only a few reports about MIPs starting from 2014.…”