Oriented docking of the template for improved imprinting efficiency toward peptide with modifications.

Molecular imprinting polymers (MIPs) are synthetic receptors as biomimetic materials for various applications ranging from sensing to separation and catalysis. However, currently existing MIPs are stuck to some of the issues including the longer preparation steps and poor performance. In this report, a facile and one-pot strategy by integrating the in-situ growth of magnetic nanoparticles and reversed phase microemulsion oriented molecularly imprinting strategy to develop magnetic molecular imprinted nanocomposites was proposed. Through self-assembling of the template, it brought up highly ordered and uniform arrangement of the imprinting structure, which offered faster adsorption kinetic as adsorption equilibrium was achived within 15 min, higher adsorption capacity (Qmax = 48.78 ± 1.54 µmol/g) and high affinity (Kd = 127.63 ± 9.66 µM) toward paradigm molecule-adenosine monophosphate (AMP) compared to the conventional bulk imprinting. The developed MIPs offered better affinity and superior specificity which allowed the specific enrichment toward targeted phosphorylated peptides from complex samples containing 100-fold more abundant interfering peptides. Interestingly, different types of MIPs can be developed which could targetly enrich the specific phosphorylated peptides for mass spectrometry analysis by simply switching the templates, and this strategy also successfully achieved imprinting of macromolecular peptides. Collectively, the approach showed broad applicability to target specific enrichment from metabolites to phosphorylated peptides and providing an alternative choice for selective recognition and analysis from complex biological systems.

Study of the evolution of 3-MCPDEs and GEs in the infant formula production chain employing a modified indirect method based on magnetic solid phase extraction.

Herein, a modified indirect method was established for the determination of 3-monochloropropane-1,2-diol esters (3-MCPDEs) and glycidyl esters (GEs), employing magnetic solid phase extraction by boronic acid-functionalized magnetic nanoparticles to replace the traditional clean-up procedure. Compared with routine methods, it has been proved to be more sensitive with limits of detection in the range of 0.02-1.5 µg/kg and less susceptible to contamination of phenylboronic acid derivatives and fatty acid methyl esters. The proposed method was applied to analyze 42 samples covering the entire infant formula (IF) production chain. Results revealed that homogenization process contributed 79-91 % of the total growth of the contaminants due to the vegetable oil addition, while the following evaporation and spray-drying processes contributed 9-21 % of the total growth owing to involved heat treatment. The GE levels in final IF products exceeded the maximum level set by EU regulation 2020/1322, indicating quality safety concerns in the production chain.

Boron-doped titania for separation and purification of lactoferrin in dairy products.

Lactoferrin (LF), a natural iron regulating glycoprotein, exists in animal milk and plays multiple beneficial roles. Bovine LF is obtained by separation and purification from cow's milk, and has been added as a food additive to functional foods and infant formula now. Therefore, accurate analysis of LF in these foods is very important, but there are challenges such as poor selective extraction and separation efficiency. In this work, considering the cis-diol in LF, boron-doped titania (B-doped TiO2) material was prepared for selectively enrich LF from dairy products. In order to increase the saturation capacity of extracted LF, the amount of boron for doping was optimized, and maximum binding capacity of 63.9 mg g-1 was achieved when the atomic ratio of B to Ti was 1.65 with improved affinity in terms of KD value. In addition, the primary parameters affecting extraction efficiency such as extraction time, extraction pH, desorption time, and desorption solution were also optimized. The method of dispersive solid phase extraction based on B-doped TiO2 combined with ultra-high performance liquid chromatography-ultraviolet detection (UHPLC-UV) was developed and validated. The material greatly reduced the cost of sample pretreatment and the method also was applied to detect the LF in different dairy products such as liquid milk, fermented milk, and infant formula. This method could be used for routine analysis, separation and purification of LF.

Diethylenetriamine assisted functionalization of boronic acid on poly GMA-MAA-DVB for selective enrichment of glycoproteins and glycopeptides.

Cis-diol compounds are class of biomolecules including nucleosides, glycoproteins, saccharides, and nucleotides, which play vital roles in various biological processes. Due to low abundances of these species in the complex biological samples, their identification and analysis is difficult. Boronate affinity materials are commonly used for the isolation and enrichment of cis-diol compounds, due to their unique, facile and selective enrichment mechanism. In this study we report a selective approach to extract nucleosides, glycopeptides and glycoproteins using boronic acid functionalized GMA-MAA-DVB polymer. This novel polymer, reported for the first time in proteomics, have high BET surface area (132.8447 m2 g-1) which contribute to efficient enrichment and average pore size (20.3449 nm) to facilitates the nano confinement effect for strong interactions. Hydrophilic character of methacrylic acid and diethylenetriamine, along with inherent affinity of boronic acid for glycosylated biomolecules result in selectivity up to 1:500 for peptides and 1:1000 for glycoprotein. Binding constant for cis-diol compounds are in the range of 10-4 to 10-6 M and theoretical binding capacity up to 85 mg g-1 for HRP and 180 mg g-1 for IgG, respectively. Furthermore, boronic acid functionalized polymer (BFP) enrich glycoproteins and glycopeptides in range of 1 pg mL-1 and 0.04 ng mL-1 with S/N ≥ 3. Finally, material is applied to enrich the glycoproteins from healthy human saliva sample and six glycoproteins are identified.