Supramolecular Assembly of Aminoethylene‐Lipopeptide PMO Conjugates into RNA Splice‐Switching Nanomicelles

Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile.     

Long-term sensor measurements of lung deposited surface area of particulate matter emitted from local vehicular and residential wood combustion sources

Abstract

Lung deposited surface area (LDSA) is a relatively new metric that has been argued to be more accurate at predicting health effects from aerosol exposure. For typical atmospheric aerosol, the LDSA concentration depends mainly on the concentration of ultrafine particles (e.g. vehicular exhaust emissions and residential wood combustion) and therefore optical methods cannot be used to measure and quantify it. The objective of this study was to investigate and describe typical characteristics of LDSA under different urban environments and evaluate how a diffusion charging-based Pegasor AQ Urban sensor (Pegasor Ltd., Finland) can be used as an alternative to optical sensors when assessing local combustion emissions and respective LDSA concentrations. Long-term (12?months) sensor measurements of LDSA were carried out at three distinctly different measurement sites (four sensor nodes) in the Helsinki metropolitan area, Finland. The sites were affected mainly by vehicular exhaust emission (street canyon and urban background stations) and by residential wood combustion (two detached housing area stations). The results showed that the accuracy of the AQ Urban was good (R² = 0.90) for the measurement of LDSA when compared to differential mobility particle sizer. The mean concentrations of LDSA were more than twice as high at the street canyon (mean 22 µm² cm^?3) site when compared to the urban background site (mean 9.4 µm² cm^?3). In the detached housing area, the mean concentrations were 12 µm² cm^?3, and wood combustion typically caused high LDSA peaks in the evenings. High correlations and similar diurnal cycles were observed for the LDSA and black carbon at street canyon and urban background stations. The utilization of a small-scale sensor network (four nodes) showed that the cross-station variability in hourly LDSA concentrations was significant in every site, even within the same detached housing area (distance between the two sites ～670?m).     

Comparative examination of adhesive and cohesive properties of fluorinated coatings on stone/tile surfaces

A NanoScratch methodology was used to evaluate the relative adhesive and cohesive strength of fluorinated poly(methyl methacrylate-co-methacrylic acid) and fluorinated phosphate coatings on stone and tile surfaces. In general, all coatings showed ability to bind to the stone and tile surfaces, and polymer-based coatings expressed stronger adhesion compared to a small-molecule fluorinated phosphate coating. Also, anionic fluorinated polymers containing methacrylic acid (MAA) residues in the ammonium carboxylate form adhered more strongly compared to corresponding acidic polymer counterparts. In addition, anionic fluorinated polymers, shown to adhere more strongly to granite than marble, possibly due to strong Lewis acid-base interaction between carboxylate and aluminosilicates. Conversely, the fluorinated polymers, bearing the MAA side-chains in their free-acid form, bound more strongly to marble via possible Brønsted acid-base interactions between carboxylic acid and calcium carbonate. Lastly, in most cases, comparable fracture thresholds were observed for the same coating material on different substrates. This was expected since fracture threshold is a measure of the mechanical strength of the coating material, independent of the substrate difference.     

Determination of copper complexing capacity of natural river water, well water and artificially reconstituted water

A cupric ion electrode and computerized chemical equilibrium model were used to determine the copper complexing capacity of several natural river waters, well water and two artificially reconstituted waters. After adding a series of copper spikes to each water, the cupric ion concentration was measured and a comparison was made with cupric ion concentrations predicted by a chemical equilibrium model. Plots of cupric ion concentration vs total copper concentration (complexing capacity curves) were nonlinear at the lower total copper concentrations for several of the natural river waters. The slope of the linear portion of the complexing capacity curves was a function of pH and total alkalinity. For the natural river waters investigated, measured cupric ion concentrations were nearly always less than the theoretically computed cupric ion concentrations, while for two different artificially reconstituted waters and well water, reasonably quantitative agreement resulted.