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Conversion of inorganic selenium (Se) to its organic form by Saccharomyces cerevisiae(S. cerevisiae) has attracted significant attention, for organic Se has higher nutritional value with less negative effects. However, the mechanism of transformation and accumulation of organic Se at the metabolic level remains unclear. We investigated the metabolic response to sodium selenite supplementation in culture medium at 0, 5, 15, and 45 mg/L in two S. cerevisiaestrains using an ultra-high performance liquid chromatography-high resolution mass spectrometry-based untargeted method. In total, 455 metabolites were detected, and a separation trend was clearly observed between Se-treated groups and controls. In depth, metabolic pathways involving amino acid, nucleotide metabolism and tricarboxylic acid cycle were significantly affected. Furthermore, high inorganic-Se supplementation effectively decreased the seleno-amino acid proportion in total Se, inhibited cell growth, and decreased glutathione levels. These results provide novel insights into the Se-enrichment process of S. cerevisiae.

Biomimic mineralization of hard tissues with hierarchical structures is a challenging task, while designing multifunctional materials possessing both the ability of biomimic mineralization and drug delivery is even more difficult. Herein, inspired by the multilevel structure and mineralization ability of amelogenin, a novel carboxyl-functionalized covalent organic framework (COF) nanosphere material was designed and synthesized, which exhibited a significant biomimetic remineralization ability as demonstrated on SiO2glass, Ti6Al4V, and an acid-etched enamel surface. Furthermore, the nanoporous structure also enables the COF nanospheres to serve as a drug delivery system for the controlled release of antibacterial drugs. This work provides a promising strategy for the design of multifunctional biomimic materials.