Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)最新文献

A combined electrical (HV, “high voltage”, pulsing) and chemical (topical sodium thiosulfate) intervention is hypothesized to create enlarged aqueous pathways that allow large quantities of macromolecules to be transported through human skin's stratum corneum (SC), the dominant barrier for transdermal drug delivery and biochemical analyte extraction. This expectation is based on the known structure and composition of the SC, and previous models and experiments for local transport regions (LTRs) due to transdermal HV pulsing. In vitro experiments demonstrated that transdermal macromolecule fluxes of 10⁻⁹ to 10⁻⁸ mol h⁻¹ cm⁻² (10 to 100 μg h⁻¹ cm⁻²) or greater are possible for lactalbumin and an antibody (IgG), which are potentially therapeutic values for peptides, proteins and nucleic acids. In the absence of sodium thiosulfate, only a small molecule (sulforhodamine) flux increased significantly, consistent with many previous studies. Significant macromolecule transdermal fluxes occurred only if a pathway enlarging molecule (sodium thiosulfate) was present. Our results also provide support for the mechanism hypothesis that HV pulses leading to transdermal voltages U_skin>50 V create straight-through aqueous pathways that penetrate multilamellar bilayer membranes, corneocyte envelopes and corneocyte interiors within the SC.

The effect of 8.15–18 GHz (1 Hz within) microwave radiation at a power density of 1 μW/cm² on the tumor necrosis factor (TNF) production and immune response was tested. A single 5 h whole-body exposure induced a significant increase in TNF production in peritoneal macrophages and splenic T cells. The mitogenic response in T lymphocytes increased after microwave exposure. The activation of cellular immunity was observed within 3 days after exposure. The diet containing lipid-soluble nutrients (β-carotene, α-tocopherol and ubiquinone Q₉) increased the activity of macrophages and T cells from irradiated mice. These results demonstrate that irradiation with low-power density microwaves stimulates the immune potential of macrophages and T cells, and the antioxidant treatment enhances the effect of microwaves, in particular at later terms, when the effect of irradiation is reduced.

Measurements of skin electrical admittance were performed on the leg in healthy controls and patients with ischemia. The experiments were carried out using sinusoidal wave voltage at seven frequencies from 100 Hz to 100 kHz applied using two electrodes. The character of the frequency dependencies of admittance for both groups arises from stratum corneum — in the frequencies up to 10 kHz, and the underlying tissue of skin, above this frequency. Legs change their passive electrical properties due to ischemia. The measured data are interpreted as cell membranes become more permeable and thus an efflux of intracellular electrolyte.

Polyions complex 2C₁₂N⁺PSS⁻ was prepared by reacting poly(sodium styrenesulfonate) (Na⁺PSS⁻) with didodecyldimethylammonium bromide (2C₁₂N⁺Br⁻). Stable thin films made from 2C₁₂N⁺PSS⁻ with incorporated redox protein hemoglobin (Hb) on pyrolytic graphite (PG) electrodes were then characterized by electrochemistry and other techniques. Cyclic voltammetry (CV) of Hb–2C₁₂N⁺PSS⁻ films showed a pair of well-defined and nearly reversible peaks for HbFe(III)/Fe(II) couple at about −0.17 V vs. saturated calomel electrode (SCE) in pH 5.5 buffers. The electron transfer rate between Hb and PG electrode was greatly facilitated in microenvironment of 2C₁₂N⁺PSS⁻ films. Positions of Soret absorption band suggest that Hb keeps its secondary structure similar to its native state in 2C₁₂N⁺PSS⁻ films at the medium pH. The results of X-ray diffraction and differential scanning calorimetry (DSC) suggest synthesized lipid 2C₁₂N⁺PSS⁻ films have an ordered bilayer structure intercalated between PSS⁻ polyion layers, and the incorporated Hb expands the layer spacing of the films. HbFe(I), a highly reduced form of Hb, might also be produced in these films at about −1.09 V, and could be used to catalytically reduce organohalide pollutants.