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Sulfonylureas, a family of anti-diabetic drugs widely used in the clinical treatment of type 2 diabetes, have recently emerged as an illegal adulterant in functional foods, to enhance the claimed anti-diabetic activity. To establish a screening assay method against their adulteration, with the aid of molecular simulation of hapten, two antibodies were raised and complementarily used to enhance the broad-specificity of an enzyme-linked immunosorbent assay (ELISA), which demonstrated simultaneous detection capability to 6 sulfonylureas; the detection limits ranged from 0.02 to 1.0 ng/mL, and recoveries were between 78.3% to 104.5%. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) confirmed the reliability of the proposed ELISA, based on real samples. These results suggest that the proposed ELISA could be an ideal method for screening to monitor for illicit adulteration of sulfonylureas in functional pill products.

Propiconazole (PCZ) is a fungicide popularly used to prevent and control wheat and rice bakanae disease, etc. However, it was recently found to be illegally employed as a plant regulator to induce thick stems and dark green leaves of Brassica campestris, a famous vegetable in Guangdong, South China. Due to a lack of available recognition molecules to the target analyte, it is still a big challenge to establish a rapid surveillance screening method. In this study, a novel chiral hapten was rationally designed, and an artificial immunogen was then prepared for the generation of a specific antibody against propiconazole for the first time. Using the obtained antibody, a highly sensitive time-resolved fluorescence microspheres lateral flow immunochromatographic assay (TRFMs-LFIA) was established with a visual limit of detection of 100 ng/mL and a quantitative limit of detection of 1.92 ng/mL for propiconazole. TRFMs-LFIA also exhibited good recoveries ranging from 78.6% to 110.7% with coefficients of variation below 16%. The analysis of blind real-life samples showed a good agreement with results obtained using HPLC-MS/MS. Therefore, the proposed method could be used as an ideal screening surveillance tool for the detection of propiconazole in vegetables.

Nanotechnology approaches play an important role in developing novel and efficient carriers for biomedical applications. Peptides are particularly appealing to generate such nanocarriers because they can be rationally designed to serve as building blocks for self-assembling nanoscale structures with great potential as therapeutic or diagnostic delivery vehicles. In this review, we describe peptide-based nanoassemblies and highlight features that make them particularly attractive for the delivery of nucleic acids to host cells or improve the specificity and sensitivity of probes in diagnostic imaging. We outline the current state in the design of peptides and peptide-conjugates and the paradigms of their self-assembly into well-defined nanostructures, as well as the co-assembly of nucleic acids to form less structured nanoparticles. Various recent examples of engineered peptides and peptide-conjugates promoting self-assembly and providing the structures with wanted functionalities are presented. The advantages of peptides are not only their biocompatibility and biodegradability, but the possibility of sheer limitless combinations and modifications of amino acid residues to induce the assembly of modular, multiplexed delivery systems. Moreover, functions that nature encoded in peptides, such as their ability to target molecular recognition sites, can be emulated repeatedly in nanoassemblies. Finally, we present recent examples where self-assembled peptide-based assemblies with “smart” activity are used in vivo. Gene delivery and diagnostic imaging in mouse tumor models exemplify the great potential of peptide nanoassemblies for future clinical applications.