Nanocarrier systems are currently being developed for peptide, protein and gene delivery to protect them in the blood circulation and in the gastrointestinal tract. Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with a new antimicrobial GIBIM-P5S9K peptide were obtained by the double emulsion solvent extraction/evaporation method. PLA- and PLGA-NPs were spherical with sizes between 300 and 400 nm for PLA and 200 and 300 nm for PLGA and 20 mV. The peptide-loading efficiency of PLA-NP and PLGA-NPs was 75% and 55%, respectively. PLA- and PLGA-NPs released around 50% of this peptide over 8 h. In 10% human sera the size of peptide loaded PLA- and PLGA-NPs increased between 25.2% and 39.3%, the PDI changed from 3.2 to 5.1 and the surface charge from −7.15 to 14.6 mV. Both peptide loaded PLA- and PLGA-NPs at 0.5 μ M peptide concentration inhibited the growth of Escherichia coli O157:H7 ( E . coli O157:H7 ), methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. aeruginosa (P. aeruginosa) . In contrast, free peptide inhibited at 10 μ M but did not inhibit at 0.5 and 1 μ M. These PLA- and PLGA-NPs presented <10% hemolysis indicating that they are hemocompatible and promising for delivery and protection system of GIBIM-P5S9K peptide.

C343, a common molecular probe utilized in solvation dynamics experiments, was studied in homogeneous media. Absorption, emission, and ¹HNMR spectroscopies were used to investigate the behavior of C343 in benzene and in benzene/n-heptane mixtures. We demonstrate the implications of the medium polarity, measured as the Kamlet−Taft polarity-polarizability (π*) parameter, in the C343 inter/intramolecular hydrogen bond (H-bond) interactions and the role that this interaction plays in the dimerization process of the dye. In pure benzene, the dimer prevails because the intermolecular H-bond interaction is favored. On the other hand, as the n-heptane content increases the intramolecular H-bond is the strongest and the C343 monomer is favored. As the polarity of the medium decreases, the solvophobic interaction makes that C343 monomer species experiences a more complicated aggregation process beyond the simple monomer dimer equilibrium present in pure benzene. Thus, the addition of n-heptane to the mixture yields a C343 higher-order aggregates species. Thus, our work reveals the importance that the medium has on the behavior of a widespread dye used as chromophore for very different systems such as homogeneous and microheterogenous media. This is very important since the use of chromophores without understanding its chemistry can induce artifacts into the interpretation of solvation dynamics in heterogeneous environments, in particular, those provided by biological systems such as proteins. Considerable care in choosing and characterizing the system is required to analyze the results fully.

We report the effect of the molar ratio parameter W₀ (W₀ = [water]/[surfactant]) and the external organic media composition on benzyl-n-hexadecyldimethylammonium chloride (BHDC) reverse micelle (RM) interactions, the key step to nanoparticle synthesis using RMs as nanoreactors. The results show a better interaction between BHDC RM droplets when the external media contain toluene:hexane blends instead of pure toluene. This organic solvent mixture enhances the material exchange between droplets and more well defined and smaller gold nanoparticles were obtained at the two W₀ studied (3 and 6). On the other hand, BHDC RMs created in pure toluene give a stiffer environment with poor droplet–droplet interaction, and the Cl⁻ counterions affect the growth of the particles, leading to different morphologies and sub-nanometer gold species production. These results are very promising for many applications. This work shows how each RM system is a unique and tunable nanoreactor.

This study presents the use of the modified coffee husk and coffee lignin as sorbents in the heavy metal ions sorption of Pb(II), Cd(II), Cr(III), and Cu(II) in an aqueous solution. The modification of sorbents was carried out by the impregnation method, using silver nitrate (AgNO₃) and sodium borohydride (NaBH₄) as a nanoparticles’ (NPs) precursor, and reducing agent, respectively. The obtained nanocomposite material was morphologically characterized by electron microscopy. In addition, an evaluation of metal ions’ sorption, pseudo-first-order, and pseudo-second-order kinetics modeling was performed. Finally, antifungal activity was evaluated on different Candida species. Coffee and lignin modified with AgNPs increased the extraction capacity with the highest sorption for Pb ions with 2.56 mg/g and 1.44 mg/g, respectively.