Molecularly imprinted mesoporous silica nanoparticles for specific extraction and efficient identification of Amadori compounds.

Amadori compounds are an important family of chemical species with high values in the quality control and research of food and tobacco products as well as disease diagnosis. Since they are present in a large population with close structure and nature, recognition of specific Amadori compounds from complex sample matrices presents a challenging task. Particularly, few reagents or materials that can recognize specific Amadori compounds have been reported. In this study, we synthesized molecularly imprinted mesoporous silica nanoparticles (MIMSNs) that can highly specifically recognize and efficiently extract an Amadori compound of interest from complex samples. N-(1-deoxy-d-glucose-1-yl)tryptophan (Glc-Trp), a typical Amadori compound, was used as the template and target compound. The prepared MIMSNs exhibited excellent binding properties. The cross-reactivity was only 2.9-4.8% towards interfering analogs. The binding constant and binding capacity towards the target were 66 µM and 45 µmol/g, respectively. The imprinting approach showed outstanding imprinting effect, giving an imprinting factor of 119.4. Through combining MIMSNs-based extraction with electrospray ionization-mass spectrometry (ESI-MS) and capillary electrography (CE), a targeted analysis approach was established and demonstrated to be an efficient platform for identification and determination of Glc-Trp from cigarette sample.

Highly Efficient Solid-Phase Labeling of Saccharides within Boronic Acid Functionalized Mesoporous Silica Nanoparticles.

Labeling is critical for the detection, quantitation, and structural identification of saccharides. However, conventional liquid-phase labeling suffers from apparent disadvantages, such as time-consuming, the presence of excessive labeling reagent, and high applicable saccharide concentration. A solid-phase approach is presented for highly efficient labeling of saccharides, using boronic acid functionalized mesoporous silica nanoparticles (MSNs) as a selective extraction sorbent and nanoscale reactor. The solid-phase labeling approach exhibited several significant advantages, including: much faster reaction speed (taking only 2 min), high product purity, and much lower applicable saccharide concentration (four orders of magnitude lower than that of liquid-phase labeling). Thus, this labeling approach opens up new avenues to the facile and efficient labeling of saccharides.

A high boronate avidity monolithic capillary for the selective enrichment of trace glycoproteins.

Boronate affinity materials, as effective sample enrichment sorbents for glycoproteomic analysis, have attracted increasing attention in recent years. However, most of boronate affinity materials suffer from an apparent limitation, limited binding strength. As a result, extraction of glycoproteins of trace concentration is rather difficult or impossible. In this study, we present a high boronate avidity monolithic capillary. Branched polyethyleneimine (PEI) was used as a scaffold to amplify the number of boronic acid moieties. While 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA), which exhibited ultrahigh affinity toward cis-diol-containing compounds, was employed as an affinity ligand. Due to the PEI-assisted synergistic multivalent binding, the monolithic column exhibited high boronate avidity toward glycoproteins, with binding constants of 10(-6)-10(-7)M. Such binding strength was the highest among already reported boronic acid-functionalized materials that can be used for glycoproteomic analysis. Besides, the boronate avidity monolithic column exhibited one additional beneficial feature, lowered binding pH (≥6.5). These features greatly favored the selective enrichment of trace glycoproteins from real samples. The feasibility for practical applications was demonstrated with the selective enrichment of trace glycoproteins in human saliva. As compared with other boronate avidity/affinity materials, the boronate avidity monolithic capillary exhibited the best performance.