Quantification of intracellular payload release from polymersome nanoparticles

Polymersome nanoparticles (PMs) are attractive candidates for spatio-temporal controlled delivery of therapeutic agents. Although many studies have addressed cellular uptake of solid nanoparticles, there is very little data available on intracellular release of molecules encapsulated in membranous carriers, such as polymersomes. Here, we addressed this by developing a quantitative assay based on the hydrophilic dye, fluorescein. Fluorescein was encapsulated stably in PMs of mean diameter 85 nm, with minimal leakage after sustained dialysis. No fluorescence was detectable from fluorescein PMs, indicating quenching. Following incubation of L929 cells with fluorescein PMs, there was a gradual increase in intracellular fluorescence, indicating PM disruption and cytosolic release of fluorescein. By combining absorbance measurements with flow cytometry, we quantified the real-time intracellular release of a fluorescein at a single-cell resolution. We found that 173 ± 38 polymersomes released their payload per cell, with significant heterogeneity in uptake, despite controlled synchronisation of cell cycle. This novel method for quantification of the release of compounds from nanoparticles provides fundamental information on cellular uptake of nanoparticle-encapsulated compounds. It also illustrates the stochastic nature of population distribution in homogeneous cell populations, a factor that must be taken into account in clinical use of this technology.</p

(Photo)physical properties of new molecular glasses end-capped with thiophene rings composed of diimide and imine units

New symmetrical arylene bisimide derivatives formed by using electron-donating-electron-accepting systems were synthesized. They consist of a phthalic diimide or naphthalenediimide core and imine linkages and are end-capped with thiophene, bithiophene, and (ethylenedioxy)thiophene units. Moreover, polymers were obtained from a new diamine, N,N′-bis(5- aminonaphthalenyl)naphthalene-1,4,5,8-dicarboximide and 2,5- thiophenedicarboxaldehyde or 2,2′-bithiophene-5,5′-dicarboxaldehyde. The prepared azomethine diimides exhibited glass-forming properties. The obtained compounds emitted blue light with the emission maximum at 470 nm. The value of the absorption coefficient was determined as a function of the photon energy using spectroscopic ellipsometry. All compounds are electrochemically active and undergo reversible electrochemical reduction and irreversible oxidation processes as was found in cyclic voltammetry and differential pulse voltammetry (DPV) studies. They exhibited a low electrochemically (DPV) calculated energy band gap (Eg) from 1.14 to 1.70 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels and Eg were additionally calculated theoretically by density functional theory at the B3LYP/6-31G(d,p) level. The photovoltaic properties of two model compounds as the active layer in organic solar cells in the configuration indium tin oxide/poly(3,4-(ethylenedioxy)thiophene):poly(styrenesulfonate)/active layer/Al under an illumination of 1.3 mW/cm2 were studied. The device comprising poly(3-hexylthiophene) with the compound end-capped with bithiophene rings showed the highest value of Voc (above 1 V). The conversion efficiency of the fabricated solar cell was in the range of 0.69-0.90%

Use of nasal packing as a splint for stabilizing nasal alar repairs

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The cause and progress of the endogenous coal fire in the remediated landfill in the city of Katowice

Slopes of the abandoned municipal waste landfill in the city of Katowice remediated in 1998 have been thermally active since 2007. The thermal activity was caused by spontaneous coal combustion within the sub-surface (0.5–1.5 m below ground level) layer of coal mine waste used for engineering the landfill. Exploitation of biogas from the landfill prior to thermal events may have enhanced exothermic oxidation of coal waste. The smoldering is the prevalent and persistent form of coal combustion in the landfill and is responsible for high emissions of CO (up to 3%), CO2 (>18%), methane and a suite of gaseous hydrocarbons. Attempts to extinguish coal fire did not prevent the advance of smoldering front at a rate of tens of metres per year

Investigation of thermal interface materials reinforced with micro- and nanoparticles

Heat management is one of the major challenges in modern electronic devices. The higher performance results in a production of greater amount of heat which needs to be efficiently dissipated so as to ensure the electronic devices operational during the period of lifetime. This paper discusses the application of micro- and nano-materials in thermal interface materials (TIM) used for heat management. Effects of type, size and geometry of different fillers were experimentally investigated. The results showed that it is recommended to utilize silver particles compared to copper ones to achieve higher heat dissipation. And the particles of smaller size may enhance the thermal conductivity of elaborated materials