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1.
Nanoscale ; 13(31): 13353-13367, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477741

RESUMO

Despite the significance of surface absorbed proteins in determining the biological identity of nanoparticles (NPs) entering the human body, little is known about the surface corona and factors that shape their formation on dietary particles used as food additives. In this study, food grade NPs of silica and titania and their food additive counterparts (E551 and E171) were interacted with milk proteins or with skimmed milk and the levels of protein adsorption were quantified. Characteristics of proteins correlating with their level of adsorption to NPs were determined using partial least squares regression analysis. Results from individual protein-particle interactions revealed the significance of factors such as zeta potential, hydrophobicity and hydrodynamic size of particles, and protein characteristics such as the number of beta strands, isoelectric points, the number of amino acid units (Ile, Tyr, Ala, Gly, Pro, Asp, and Arg), and phosphorylation sites on their adsorption to particles. Similar regression analysis was performed to identify the characteristics of twenty abundant and enriched proteins (identified using LC-MS/MS analysis) for their association with the surface corona of milk-interacted particles. Contrary to individual protein-particle interactions, protein characteristics such as helices, turns, protein structures, disulfide bonds, the number of amino acid units (Cys, Met, Leu, and Trp), and Fe binding sites were significant for their association with the surface corona of milk interacted particles. This difference in factors identified from individual proteins and milk interacted particles suggested possible interactions of proteins with surface adsorbed biomolecules as revealed by scanning transmission X-ray microscopy and other biochemical assays.


Assuntos
Nanopartículas , Coroa de Proteína , Adsorção , Sequência de Aminoácidos , Cromatografia Líquida , Humanos , Proteoma , Espectrometria de Massas em Tandem
2.
J Agric Food Chem ; 67(44): 12264-12272, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31613615

RESUMO

While silica particles are used extensively in food products, different grades and temperature variants of silica particles have not been compared for their physiochemical and biological properties. Different grades of silica (food-grade nanoparticles (FG-NPs), nonfood-grade nanoparticles (NFG-NPs), and food-grade micron particles (FG-MPs)) and the temperature variants generated by exposing FG-NPs to wet heating, dry heating, and refrigeration were compared for their physicochemical properties and interaction with trypsin. FG-NPs were similar to NFG-NPs and FG-MPs in their elemental composition and amorphous nature but had relatively less branched and ring siloxane groups than the latter ones. There were subtle but noticeable changes in the agglomeration behavior and relative abundance of different silica groups in FG-NPs exposed to food-handling temperatures. Secondary structure and function of trypsin were negatively impacted by FG-NPs and their temperature variants. Silica particles showed a "mixed-type inhibition" of trypsin resulting in partial digestion of bovine serum albumin. In conclusion, our studies showed differences in the surface chemistry of different grades of silica particles and temperature variants of FG-NPs and their negative impact on the structure and function of trypsin.


Assuntos
Aditivos Alimentares/química , Nanopartículas/química , Dióxido de Silício/química , Tripsina/química , Animais , Biocatálise , Bovinos , Hidrodinâmica , Tamanho da Partícula , Soroalbumina Bovina/química , Propriedades de Superfície , Temperatura
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