Biodegradable nanoparticles loaded with tetrameric melittin: preparation and membrane disruption evaluation

Abstract. Melittin is the main component of bee venom consisting of 26 amino acids that has multiple effects, including antibacterial, antiviral and anti-inflammatory in various cell types. This peptide forms pores in biological membranes and triggers cell death. Therefore it has potential as an anticancer therapy. However, the therapeutic application of melittin is limited due to its main side effect, hemolysis, which is especially pronounced following intravenous administration. In the present study, we formulated tetrameric melittin-carrying poly-D,L-lactic-co-glycolic acid nanoparticles (PLGANPs) and analyzed the lytic activity of this system on liposomes that resembles breast cancer cells. Tetrameric melittin binds avidly to PLGA-NPs with an encapsulation efficiency of 97% and retains its lytic activity demonstrating the effectiveness of PLGA-NPs as nanocarriers for this cytolytic peptide. Key words: Melittin — PLGA nanoparticles — Liposomes — Leakage — Fluorescence — Circular dichrois

Nanoencapsulated laccases obtained by double-emulsion technique. Effects on enzyme activity ph-dependence and stability

One primary drawback of enzyme catalysis at industrial scale is the short-term service life of the enzymes, they lose their activity due to oxidation or other processes which results in less stability and a shorter lifetime thereby rendering them less efficient. An effective way to increase the stability of the enzymes is to attach them to nanoparticles. In this work, the polymer Eudragit® L 100-55 sensitive to pH was used to prepare laccase polymeric nanoparticles by the double-emulsion solvent evaporation approach. The size and morphology of the nanoparticles obtained were evaluated—as well as the encapsulation efficiency and zeta potential. pH effect on activity and stability was compared between free and immobilized laccase. Their stability was also determined in a sequential assay involving acidic pHs up to alkaline ones. The nanoparticles had a spherical shape with a mean size of 147 nm, zeta potential of −22.7 mV at pH 7.0 and load efficiency of 87%. The optimum pH of both free and immobilized laccases was 3.0, being the nanoparticles more stable at acidic pHs. Thus, this would be the first report of obtaining laccase nanoparticles with potential application in animal feed due to the stability conferred to enzymatic activity at pHs similar to those present in the gastrointestinal tract of rabbits, which would allow their potential use in animal feed.Fil: Chong Cerda, Rocío. Universidad Autonoma de Nuevo Leon.; MéxicoFil: Levin, Laura Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Castro Ríos, Rocío. Universidad Autonoma de Nuevo Leon.; MéxicoFil: Hernández Luna, Carlos Eduardo. Universidad Autonoma de Nuevo Leon.; MéxicoFil: González Horta, Azucena. Universidad Autonoma de Nuevo Leon.; MéxicoFil: Gutiérrez Soto, Guadalupe. Universidad Autonoma de Nuevo Leon.; MéxicoFil: Chávez Montes, Abelardo. Universidad Autonoma de Nuevo Leon.; Méxic

A new RP-HPLC method as an auxiliary tool for optimization of sample preparation procedures for tracing of PPCPs of different hydrophilicities

Recently, pharmaceutical and personal care products (PPCPs) have received considerable attention because of their increasing use. Analysis of PPCPs presents a significant analytical challenge, with high-performance liquid chromatography (HPLC) in reversed-phase mode, as the most widely used analytical technique. To facilitate the optimization of the procedures that are applied in the early stages of sample preparation, a simple and fast HPLC method is proposed in this work for the separation of some PPCPs with a wide range of hydrophilicity. Two columns were evaluated (Atlantis dC18 and Discovery HS F5); as for mobile phases: a formate buffer (40 mmol L-1, pH 4) and methanol were tested in a gradient mode. The fluorinated column allowed better separation in a shorter time and better resolution for all analytes (Rs >1). The proposed method delivered good performance for the tracing of PPCPs and is a suitable alternative to traditional C18-based HPLC methods

Nanotecnología aplicada al desarrollo de películas inteligentes para la conservación de productos hortofrutícolas.

La calidad de productos hortofrutícolas se ve afectada por el crecimiento de microorganismos, entre los principales se encuentran hongos fitopatógenos del género Penicillum, Fusarium, Alternaria, Geotrichum y Rhizopus. Datos emitidos tras el programa federal “Cruzada nacional contra el hambre” muestran que es uno de los productos con mayor porcentaje de merma, hasta del 30 % de la producción. Para mantener la calidad de estos productos se evalúa el uso de activos naturales de piel de Punica granatum incorporados en micropartículas poliméricas sensibles a pH ácido, por lo que se aprovecha la acidez provocada por la infección. La extracción se realizó mediante la técnica de maceración con agitación en sistema metanol – agua 7:3 y etanol – agua en la misma proporción, se eliminó el solvente orgánico utilizando un rotavapor. Para la formulación de las micropartículas de 1 µm de tamaño promedio, se implementó la técnica de doble emulsión (w/o/w)- evaporación, usando el polímero Eudragit E-100. Se evaluó la actividad antifúngica contra Geotrichum candidum causante de la pudrición ácida en jitomate in vitro mediante la técnica de microdiluciones en microplaca (extracto libre y encapsulado). La formulación de micropartículas incorporadas con extracto permitirá lograr una liberación prolongada, además de ser fácilmente lavable e inocua