Heterostructures of Cu2-xS/Cu2-xTe plasmonic semiconductors: disappearing and reappearing LSPR with anion exchange.

Localized surface plasmon resonance (LSPR) of Cu2-xS nanorods is quenched during the initial Cu2-xS/Cu2-xTe core/shell stage of anion exchange then returns as Cu2-xTe progresses into the nanorod. Phase change within the core accounts for this behaviour illustrating the complexity emergent from anion exchange.

Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics.

Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described. This protein-modified reduced graphene oxide nanocomposite material shows no toxicity to mouse embryo fibroblasts and COS-7 cell cultures at a high concentration of 1600 µg mL-1 which is 160 times higher than those used in bECs, unlike the unmodified graphene oxide which caused toxic cell damage even at low doses of 10 µg mL-1. The bEC devices are 1 µm thick, fully flexible, and have high energy density comparable to that of lithium thin film batteries. COS-7 cell culture is not affected by long-term exposure to encapsulated bECs over 4 d of continuous charge/discharge cycles. These bECs are unique, protein-based devices, use serum as electrolyte, and have the potential to power a new generation of long-life, miniaturized implantable devices.

Biofunctionalization of α-zirconium phosphate nanosheets: toward rational control of enzyme loading, affinities, activities and structure retention.

Controlling the properties of enzymes bound to solid surfaces in a rational manner is a grand challenge. Here we show that preadsorption of cationized bovine serum albumin (cBSA) to α-Zr(IV) phosphate (α-ZrP) nanosheets promotes enzyme binding in a predictable manner, and surprisingly, the enzyme binding is linearly proportional to the number of residues present in the enzyme or its volume, providing a powerful, new predictable tool. The cBSA loaded α-ZrP (denoted as bZrP) was tested for the binding of pepsin, glucose oxidase (GOX), tyrosinase, catalase, myoglobin and laccase where the number of residues increased from the lowest value of ∼153 to the highest value of 2024. Loading depended linearly on the number of residues, rather than enzyme charge or its isoelectric point. No such correlation was seen for the binding of these enzymes to α-ZrP nanosheets without the preadsorption of cBSA, under similar conditions of pH and buffer. Enzyme binding to bZrP was supported by centrifugation studies, powder X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectroscopy. All the bound enzymes retained their secondary structure and the extent of structure retention depended directly on the amount of cBSA preadsorbed on α-ZrP, prior to enzyme loading. Except for tyrosinase, all enzyme/bZrP biocatalysts retained their enzymatic activities nearly 90-100%, and biofunctionalization enhanced the loading, improved structure retention and supported higher enzymatic activities. This approach of using a chemically modified protein to serve as a glue, with a predictable affinity/loading of the enzymes, could be useful to rationally control enzyme binding for applications in advanced biocatalysis and biomedical applications.

Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids).

BACKGROUND: Fertilisation of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the US, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. METHODS: To describe and document adverse effects reported by residents, 48 individuals at ten sites in the US and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, PA. Medical records were reviewed in cases involving hospitalisation or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. RESULTS: Affected residents lived within approximately 1 km of land application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs) after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately 1 in 4 of 54 individuals were infected, including 2 mortalities (septicaemia, pneumonia). This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is commonly found in the lower human colon, tends to invade irritated or inflamed tissue. CONCLUSIONS: When assessing public health risks from applying sewage sludges in residential areas, potential interactions of chemical contaminants with low levels of pathogens should be considered. An increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucus membranes and thereby compromise normal barriers to infection.

Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids).

UNLABELLED: Fertilization of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the United States, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. METHODS: To describe and document adverse effects reported by residents, 48 individuals at ten sites in the United States and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, Pennsylvania. Medical records were reviewed in cases involving hospitalization or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. RESULTS: Affected residents lived within approximately 1 km of land-application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs) after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately one in four of 54 individuals were infected, including two mortalities (septicemia, pneumonia). This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is occasionally found in the lower human colon, tends to invade irritated or inflamed tissue. CONCLUSIONS: When assessing public health risks from applying sewage sludges in residential areas, potential interactions of chemical contaminants with low levels of pathogens should be considered. An increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucous membranes and thereby compromise normal barriers to infection.