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Silver nanoparticles are one of the most important materials in the nanotechnology industry. Additionally, the protein corona is emerging as a key entity at the nanobiointerface; thus, a comprehensive understanding of the interactions between proteins and silver nanoparticles is imperative. Therefore, literature reporting studies involving both single molecule protein coronas (i.e., bovine and human serum albumin, tubulin, ubiquitin and hyaluronic-binding protein) and complex protein coronas (i.e., fetal bovine serum and yeast extract proteins) were selected to demonstrate the effects of protein coronas on silver nanoparticle cytotoxicity and antimicrobial activity. There is evidence that distinct and differential protein components may yield a “protein corona signature” that is related to the size and/or surface curvature of the silver nanoparticles. Therefore, the formation of silver nanoparticle protein coronas together with the biological response to these coronas (i.e., oxidative stress, inflammation and cytotoxicity) as well as other cellular biophysicochemical mechanisms (i.e., endocytosis, biotransformation and biodistribution) will be important for nanomedicine and nanotoxicology. Researchers may benefit from the information contained herein to improve biotechnological applications of silver nanoparticles and to address related safety concerns. In summary, the main aim of this mini-review is to highlight the relationship between the formation of silver nanoparticle protein coronas and toxicity.

Thermostable enzymes and thermophilic cell factories may afford economic advantages inFurthermore, we present evidence suggesting that aside from representing a potential 9 reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using 10 classical and molecular genetics. 11Rapid, efficient and robust enzymatic degradation of biomass-derived polysaccharides is 12 currently a major challenge for biofuel production. A prerequisite is the availability of enzymes 13 that hydrolyze cellulose, hemicellulose and other polysaccharides into fermentable sugars at 14 conditions suitable for industrial use. The best studied and most widely used cellulases and to overcome these obstacles is to raise the reaction temperature, thereby increasing hydrolytic 20 rates and reducing contamination risks. AT-rich repetitive regions (Fig. 1). one PL3 and two GH28). Pectin lyases are most active at neutral to alkaline pH whereas GH28 To examine the strategy used by these thermophiles for decomposition of plant cell wall 9 polysaccharides, we used RNA-Seq to compare transcript profiles during growth on barley straw 10 or alfalfa straw to growth on glucose. Alfalfa was chosen to represent dicotyledonous plants, 11 whereas barley was used to represent monocotyledon plants. The conditions. For example, the orthologs in Clades A, B, E, G and P of GH61 are upregulated 8 under growth in complex substrates for both thermophiles (Fig. 2b). An even more striking 9 correlation between transcript levels and orthologs is evident for the GH6 and GH7 cellulases Table 7). 14 Secretomes and exo-proteomes 15In addition to extracellular CAZymes involved in digestion of polysaccharide nutrients, the Thermophilic fungi are major components of the microflora in self-heating composts. They 9 break down cellulose at a faster rate than prodigious, mesophilic cellulase producers such as T. Fig. 8 We also investigated the possibility that thermophilic fungi possess major differences in 27 processes mediating thermophily including heat shock, oxidative stress, membrane biosynthesis, 28 chromatin structure and modification, and fungal cell wall metabolism. We compared the 29 proteins predicted to be involved in these processes in C. globosum, M. thermophila and T. 30terrestris, but were unable to find differences that can convincingly be interpreted as the Fig. 9) Thermophilic fungi are ubiquitous organisms commonly found in decomposing organic matter. 25The biotechnological utility of these fungi has been recognized for many years. enzymes from the thermophiles exhibit higher hydrolytic capacity than their counterparts from 6 mesophiles at temperatures ranging from 30 °C to 60 °C (Fig. 3). One explanation is that the 7 enzymes from the thermophiles possess higher specific activity toward lignocellulosic biomass.8

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The surface microchemical environment of graphene oxide (GO) has so far been oversimplified for understanding practical purposes. The amount as well as the accurate identification of each possible oxygenated group on the GO surface are difficult to describe not only due to the complex chemical nature of the oxidation reactions but also due to several intrinsic variables related to the production and chemical processing of GO-based materials. However, to advance toward a more realistic description of the GO chemical environment, it is necessary to distinguish the oxygenated fragments with very peculiar characteristics that have so far been treated as simply graphene oxide. In this way, small oxidized graphitic fragments adsorbed on the GO surface, named oxidation debris or carboxylated carbonaceous fragments (CCFs), have been here separated from commercially available GO. Spectroscopy and microscopy results indicated that the chemical nature of these fragments is different from that of GO. By using the decoration of GO with silver nanoparticles as a conceptual model, it was seen that the presence of oxidation debris on the GO surface greatly influences the associated kinetic processes, mainly due to the nucleation and stabilization capacity for silver nanoparticles provided by the oxidation debris fragments. Consequently, when CCFs are present, Ag nanoparticles are significantly smaller and less crystalline. Considering the GO microchemical environment pointed out here, these findings can be qualitatively extrapolated to all other covalent and noncovalent functionalizations of GO.

No abstract

Graphene oxide (GO) is a very promising material because it is easy to process, water-soluble, and chemically versatile due to the presence of oxygenated groups on its surface. GO has been used in different areas such as electronics, biosensing, and environmental remediation. To design efficient materials, especially for biosensing and for remediating pollutants, the knowledge of surface noncovalent interaction and functionalization is crucial. Recently, it has been suggested revisions on the structural models of GO because the presence of highly oxidized polyaromatic carboxylated fragments (oxidative debris) on the GO surfaces. These debris are produced during acid treatments commonly employed in GO synthesis and purification. Here we applied chemical analysis, bioassays, and atomistic simulations to study the influence of oxidative debris on the noncovalent interaction of GO sheets with an important organic pollutant (e.g., 1nitropyrene). GO samples without oxidative debris were found to be 75% more effective to adsorb 1-nitropyrene than samples with debris. Our results suggest that small (∼1 nm) oxidative debris are responsible for preventing adsorption sites on GO surfaces from being reached by potentially adsorbate molecules.

Although there are several studies reporting the promising biological efficiency of mesoporous silica nanoparticles (loaded with antitumoral drugs) against cancer cells and tumors, there are no reports on the influence of the bio-nano interface interactions on the molecular diffusion process occurring along their pores. In this context, we show here that the protein coating formed on multifunctionalized colloidal mesoporous silica nanoparticles (MSNs) dispersed in a cell culture medium decreases the release of camptothecin (CPT, a hydrophobic antitumoral drug) from the pores of MSNs. This effect is related to the adsorption of biomolecules on the nanoparticle surface, which partially blocks the pores. Parallely, the hydrophobic functionalization inside the pores can offer suitable sites for the adsorption of other molecules present in the cell culture medium depending on the hydrophobicity, size, and conformation aspects of these molecules and adsorption sites of MSNs. Thus, the molecular cargo loaded in the pores (i.e. CPT) can be replaced by specific molecules present in the dispersion medium. As a consequence, we show that a non-permeable cellular staining molecule such as SYTOX green can be incorporated in MSNs through this mechanism and internalized by cells in an artificial fashion. By extrapolating this phenomenon for applications in vivo, one has to consider now the possible manifestation of unpredicted biological effects from the use of porous silica nanoparticles and others with similar structure due to these internalization aspects.