Upconversion Nanophosphor-Involved Molecularly Imprinted Fluorescent Polymers for Sensitive and Specific Recognition of Sterigmatocystin.

Jing-Min Liu,Shuo Wang,Guo-Zhen Fang,Feng-Zhen Cao

doi:10.3390/polym9070299

Abstract

Originated from the bottom-up synthetic strategy, molecularly imprinted polymers (MIPs) possess the inherent ability of selective and specific recognition and binding of the target analytes, with their structural cavities that can match the target molecules in respect to size, shape, and functional groups. Herein, based on the high selectivity of MIPs and the fluorescence properties of the β-NaYF4:Yb3+, Er3+ upconversion nanoparticles, MIPs with both specificity and fluorescent signals are fabricated to recognize trace sterigmatocystin (ST) with high selectivity and sensitivity. The structure analogue of ST, 1,8-dihydroxyanthraquinone (DT), was employed as the template molecule, acrylamide as the functional monomer, 3-methacryloyloxypropyltrimethoxysilane as the crosslinking agent, and a new molecular imprinting technique of non-aqueous sol-gel method is used to synthesize a molecularly imprinted material with high selectivity to ST. Under optimal conditions, the fluorescence enhancement of fluorescent MIPs increased as the concentration of ST increased. In the range of 0.05–1.0 mg L−1, fluorescence enhancement and the concentration showed a good linear relationship with a detection limit of 0.013 mg L−1. Real sample analysis achieved the recoveries of 83.8–88.8% (RSD 5.1%) for rice, 82.1–87.5% (RSD 4.6%) for maize, and 80.6–89.2% (RSD 3.0%) for soybeans, respectively, revealing the feasibility of the developed method.

Highlights

Originated from the intention to create binding sites in bottom-up synthetic polymers, molecular imprinting technology (MIT) has acted as a powerful tool for preparing materials that can bind to analytes reversibly and selectively in the presence of the interferents, and has provided a promising and advantageous alternative to satisfy the need of analytical methods with high sensitivity and good reliability for food safety inspection [1,2,3,4]
Compared with the conventional fluorescence probes, like semi-conductor QDs and organic dyes, Upconversion Nanoparticles (UCNPs) possess the capability of avoiding auto-fluorescence and have long lifetimes and low photobleaching, are fit to act as the signal-reporter for the determination of target molecules against complex sample matrix
Stability

Summary

Introduction

Originated from the intention to create binding sites in bottom-up synthetic polymers, molecular imprinting technology (MIT) has acted as a powerful tool for preparing materials that can bind to analytes reversibly and selectively in the presence of the interferents, and has provided a promising and advantageous alternative to satisfy the need of analytical methods with high sensitivity and good reliability for food safety inspection [1,2,3,4]. Involvement of MIT into the design of fluorescence probes/sensors strategies produced well-performed nanophosphor-encoded imprinting polymers, combining the advantages of high selectivity of MIPs with high sensitivity of luminescence of functional nanophosphors (e.g., Quantum Dots (QDs) or upconversion nanoparticles). QDs-embedded MIPs probe has been extensively studied and applied, but suffered from high toxicity, poor anti-photobleaching, and high background interference from the sample matrix [17,20,21]

Methods

Results

Conclusion