Toxicity of silver nanoparticles, multiwalled carbon nanotubes, and dendrimers assessed with multicellular organism Caenorhabditis elegans.

Nematode Caenorhabditis elegans (C. elegans) was used to investigate the impact of silver nanoparticles (SNP), multiwalled carbon nanotubes (MWCNT), and polyamidoamine dendrimers (PAMAM) used in concentration of 1010 particle/mL. Population-based observations and gene expression analysis were employed in this study. SNP and PAMAM caused decrease in the number of live nematodes and their body length, but MWCNT did not affect the population of nematodes. Gene expression analysis revealed significant changes caused by the presence of all studied nanomaterials, and the results strongly suggest a specific metabolic response of the nematode organism to exposure to various nanomaterials. It was shown that C. elegans is a very sensitive organism capable to respond specifically to the exposure to some nanomaterials and therefore could be considered as a possible biosensor for early warning of presence of some nanoparticles.

Simultaneous transcriptome and proteome analysis of EA.hy926 cells under stress conditions induced by nanomaterials.

Today, the extensive and constantly growing number of applications in the field of nanotechnology poses a lot of questions about the potential toxicity of nanomaterials (NMs) toward cells of different origins. In our work we employed the tools of molecular biology to evaluate changes that occur in human endothelial cells at the transcriptomic and proteomic level, following 24 h of exposure to three different classes of NMs. Using microarray technology, we demonstrated that 24 h of exposure to silver nanoparticles (SNPs), multiwalled carbon nanotubes (MWCNTs) and polyamidoamine dendrimers (PAMAMs) leads to changes in 299, 1271, and 431 genes, respectively, influencing specific molecular pathways. The 2D-DIGE and mass spectrometry analysis revealed that differentially expressed proteins were involved in numerous cellular processes, for example, cytoskeletal reorganization, cell growth and proliferation, or response to stress. Both, transcriptome and proteome alterations indicate reorganization of mechanism regulating cell functioning. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1024-1034, 2019.

Determination of Propagation Rate Coefficient for the Polymerization of N-Vinylpyrrolidone in Aqueous Solution by Pulsed Electron Polymerization and Size Exclusion Chromatography.

A new method for determination of a propagation rate coefficient in radical polymerization, pulsed electron polymerization-size exclusion chromatography (PEP-SEC), has been tested on N-vinylpyrrolidone in water and shown to yield results very similar to those obtained by the well-established pulsed laser polymerization-size exclusion chromatography (PLP-SEC). A potential advantage of PEP-SEC is its applicability to studying polymerizations in nontransparent systems and lack of any additives. Series of nanosecond pulses of high-energy electrons from an accelerator generate radicals which initiate polymerization. Further analysis of the samples and data processing are the same as in PLP-SEC. The described technique can be potentially developed into a method complementary and/or comparative to PLP-SEC.

Hydroxyl radical-induced crosslinking and radiation-initiated hydrogel formation in dilute aqueous solutions of carboxymethylcellulose.

Ionizing radiation causes chain scission of polysaccharides in the absence of crosslinking agents. It has been demonstrated before that degradation of carboxyalkylated polysaccharides may be prevented, despite presence of strong electrostatic repulsing forces between chains, at very high polymer concentration in water (paste-like state) when physical proximity promotes recombination of radiation-generated polymer radicals. In such conditions, crosslinking dominates over chain scission and covalent, macroscopic gels can be formed. In an approach proposed in this work, neutralizing the charges on carboxymethylcellulose (CMC) by lowering the pH results in retracting the electrostatic repulsion between chain segments and thus allows for substantial reduction of polymer concentration required to achieve gelation due to domination of crosslinking reactions. Electron-beam irradiation of aqueous solutions of low pH containing 0.5-2% CMC results in hydrogel formation with 70% yield, while both concentration and dose determine their swelling properties. Time-resolved studies by laser flash photolysis clearly indicate strong pH influence on decay kinetics of CMC radicals.