•Silica-based polypeptide-monolithic stationary phases were designed and prepared via a one-pot process.•Silica-based polypeptide-monolithic stationary phases demonstrated not only typical HILIC but also chiral separation ability.•Nucleotides and peptides could be separated using aqueous mobile phase without any ACN.•Chiral separation of drug enantiomers was realized on the GSH-AuNP-GSH-silica hybrid monolithic column.Glutathione (GSH)-, somatostatin acetate (ST)- and ovomucoid (OV)-functionalized silica-monolithic stationary phases were designed and synthesized for HILIC and chiral separation using capillary electrochromatography (CEC). GSH, ST and OV were covalently incorporated into the silica skeleton via the epoxy ring-opening reaction between their amino groups and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS) together with polycondensation and copolymerization of tetramethyloxysilane and GPTMS. Not only could the direction and electroosmotic flow magnitude on the prepared GSH-, ST- and OV-silica hybrid monolithic stationary phases be controlled by the pH of the mobile phase, but also a typical HILIC behavior was observed so that the nucleotides and HPLC peptide standard mixture could be baseline separated using an aqueous mobile phase without any acetonitrile during CEC. Moreover, the prepared monolithic columns had a chiral separation ability to separate dl-amino acids. The OV-silica hybrid monolithic column was most effective in chiral separation and could separate dl-glutamic acid (Glu) (the resolution R = 1.07), dl-tyrosine (Tyr) (1.57) and dl-histidine (His) (1.06). Importantly, the chiral separation ability of the GSH-silica hybrid monolithic column could be remarkably enhanced when using gold nanoparticles (AuNPs) to fabricate an AuNP-mediated GSH-AuNP-GSH-silica hybrid monolithic column. The R of dl-Glu, dl-Tyr and dl-His reached 1.19, 1.60 and 2.03. This monolithic column was thus applied to separate drug enantiomers, and quantitative separation of all four R/S drug enantiomers were achieved with R ranging from 4.36 to 5.64. These peptide- and protein-silica monolithic stationary phases with typical HILIC separation behavior and chiral separation ability implied their promise for the analysis of not only the future metabolic studies, but also drug enantiomers recognition.

Mercury (Hg) is a toxic heavy metal with its biogeochemical cycling in the ocean depending on the type and behavior of the oceanic microalgae. The present work aimed to evaluate bioaccumulation and transformation of Hg by Phaeodactylum tricornutum, a typical unicellular diatom, when exposed to the extremely high level of Hg in order to understand the possible mechanisms of acute stress response. P. tricornutum can accumulate Hg (its bioaccumulation factor is at 104 level), and the 96 h EC50 was estimated to be 145 μg L−1. The amounts of surface-bound Hg being about 1.2 to 4.8 times higher than those of intracellular Hg under exposure to HgCl2 (from 20 to 120 μg L−1 concentrations) suggested that the cell wall of P. tricornutum is an important “fence” towards Hg. After entering the P. tricornutum cell, Hg underwent transformation in its chemical form via interactions with high molecular weight sulfur-containing proteins (accounting for 68% of the intracellular Hg), and glutathione as well as the induced phytochelatins (PCs) (24% Hg) which alleviated the toxicity of HgCl2. In addition, the existence of organic ligands greatly influenced the uptake and transformation behavior of P. tricornutum towards HgCl2, especially in the case of cysteine (Cys), which increased the uptake of Hg, but alleviated the toxicity of Hg towards P. tricornutum due to the fact that Cys is an important precursor for the synthesis of PCs inside the cell. The uptake process of Hg by P. tricornutum was in agreement with the Freundlich isotherm, suggesting a typical heterogeneous sorption process. More importantly, we observed the conversion of HgCl2 into methylmercury inside the P. tricornutum cells and its release into the culture solution using HPLC/CVG-AFS and GC-MS, although the mechanism needs to be further investigated.

We reported an alternative strategy to reduce disulphide bonds in peptides with Ag-nanoparticle loaded nano-TiO2 (Ag/TiO2) under UV irradiation. The feasibility of this strategy was adequately demonstrated using the model peptides oxidized glutathione, vasopressin and insulin, which contain various disulphide bonds, as well as by its application to the determination of Cd-induced phytochelatins in Phaeodactylum tricornutum.

The risk of nanoparticles (NPs) to organisms and the environment has become more noticeable alongside their rapid applications in many fields. The release of Cd2+ from CdTe-based NPs (CdTe-NPs), an important class of engineered nanomaterials, is one of the possible factors responsible for the cytotoxicity of these NPs. Based on the same CdTe core, CdTe/CdS, CdTe/ZnS and CdTe/SiO2 NPs were synthesized and their Cd2+ release rates were carefully studied based on dialysis using inductively coupled plasma mass spectrometry (ICPMS). Results obtained indicated that the Cd2+ release rates of the CdTe-NPs decreased in the order CdTe (8.78 ng mL−1 mg−1 h−1) > CdTe/CdS (2.63) > CdTe/SiO2 (0.89) > CdTe/ZnS (0.72). Phaeodactylum tricornutum was used as a model diatom for evaluating the cytotoxicity of the CdTe-NPs. Results obtained from the CdTe-NPs exposure experiments together with ICPMS and fluorescence microscopy studies suggested that the cytotoxicity of the CdTe-NPs increased along with the increase in their Cd2+ release rates. Effective coating materials such as ZnS and SiO2 for the CdTe core significantly reduced the cytotoxicity of CdTe.

In this paper, we report the bioaccumulation and transformation of cadmium (Cd) by Phaeodactylum tricornutum in the presence of ethylenediamine tetra acetic acid (EDTA) and cysteine (Cys). Both EDTA and Cys can alleviate the toxicity of Cd to P. tricornutum. Short term intracellular uptake and extracellular adsorption experiments using ICP-MS indicated that the amounts of Cd accumulated on the cell surface of P. tricornutum and inside the cell decreased along with the increase of EDTA concentration, which conformed to the prediction of the Free Ion Activity Model (FIAM). However, extracellular adsorption of Cd increased at first and then decreased along with the increase in the concentration of Cys, while intracellular uptake increased under Cys concentrations from the blank value to 4.45 µmol/L, and then tended to remain at the same level when the Cys concentration was greater than 4.45 µmol/L, and this deviated remarkably from the FIAM. The interactions of Cd with-Si-OH, -C-OH and NH2(CO)-OH on the cell wall were confirmed using FT-IR and XPS studies. The results obtained using HPLC of the phytochelatins (PCs) produced by P. tricornutum under CdCl2, Cd-EDTA and Cd-Cys stress suggested that the main reason for the different effects of EDTA and Cys on the bioaccumulation and transformation of Cd by P. tricornutum was that Cys is not only a complexing ligand to Cd, as is EDTA, but also it is a precursor of the intracellular synthesizing PCs participating in the cellular defense mechanism against Cd. Furthermore, the discovery of in vivo PCs and oxidized-PCs as well as Cd-PC2 in P. tricornutum using ESI-IT-MS provided the evidence for deactivation of Cd by the PCs, reducing Cd-toxicity to P. tricornutum.