This study addresses the effect of the degree of N-acetylation (DA ~1.4–56 %) of chitosan (CS) of low and medium molecular weight (M w ~ 9.5–13.2 and ~122–266 kDa, respectively) on the biophysical properties, colloidal stability and encapsulation efficiency of capsaicin (a lipophilic drug currently used in pain therapy) of CS-based nanocapsules (NCs). The average diameter of the NCs varied within the range of ~150–200 nm, but it was slightly higher for NCs comprising high M w CS than for those with low M w CS. The zeta potential (ζ) was highly positive and clearly dependent on the M w of CS, exhibiting a monotonic decreasing trend concomitant with the increase in DA. Both results suggest that M w and DA of CS have an effect on the disposition of the polysaccharide onto the phospholipidic surface. Synchrotron SAXS studies revealed a monotonic increase in Bragg interplanar distances (from ~55 up to ~67 Å) as a function of the DA, a finding that agrees with previous results that are consistent with the capacity of hydrophobic domains to disturb the crystalline state of gelled phospholipidic membranes. Colloidal stability studies carried out in cell-culture biological media revealed the determinant role of hydration forces, a short-range repulsive interaction, on the stability of the NCs. Finally, M w and DA of CS both influenced the encapsulation efficiency of capsaicin, thus showing the effect of the harnessed NCs shell on its capacity to encapsulate lipophilic drugs.
Francisco M. Goycoolea, Angela Valle-Gallego, Rossana Stefani, Bianca Menchicchi, Laurent David, Cyrille Rochas, Manuel J. Santander-Ortega, María J. Alonso
Plant parasitic nematodes are the most destructive group of plant pathogens worldwide and their control is extremely challenging. Plant Essential oils (EOs) and their constituents have a great potential in nematode control since they can be developed for use as nematicides themselves or can ... more
For over a century, ulcer has been a major cause of morbidity and mortality. Its treatment has progressed from vagotomy to proton pump inhibitors. However, the drugs used produce many adverse effects and are less effective than they ought to be. Therefore, there is a growing interest in alt ... more
Endophytic fungi are ubiquitous organisms found in the plants, residing intercellular or intracellular, at least for a portion of their lives without causing apparent symptoms of infection. Almost all plants are known to harbor endophytes. The choice of the plant to be used for exploring en ... more
Physicists describe how they have synthesized a new material that belongs to the iron-selenide class of superconductors, called LixFe2Se2(NH3)y, in a paper about to be published in EPJ B. The work was carried out by Ernst-Wilhelm Scheidt from the University of Augsburg and colleagues. This ... more
The U.S. federal government is significantly underestimating the costs of carbon pollution because it is using a faulty analytical model, according to a new study published in the Journal of Environmental Studies and Sciences. A more appropriate accounting of costs would pave the way to cle ... more
Springer advisory board member Vladimir V. Dmitriev, along with fellow scientists Yuriy M. Bunkov and Igor A. Fomin, have been named winners of the 2008 Fritz London Memorial Prize for their discovery and understanding of the "Phase Coherent Spin Precession and Spin Superfluidity of 3He-B." ... more