Secreted Enzyme-Responsive System for Controlled Antifungal Agent Release

Essential oil components (EOCs) such as eugenol play a significant role in plant antimicrobial defense. Due to the volatility and general reactivity of these molecules, plants have evolved smart systems for their storage and release, which are key prerequisites for their efficient use. In this study, biomimetic systems for the controlled release of eugenol, inspired by natural plant defense mechanisms, were prepared and their antifungal activity is described. Delivery and antifungal studies of mesoporous silica nanoparticles (MSN) loaded with eugenol and capped with different saccharide gates—starch, maltodextrin, maltose and glucose—against fungus Aspergillus niger—were performed. The maltodextrin- and maltose-capped systems show very low eugenol release in the absence of the fungus Aspergillus niger but high cargo delivery in its presence. The anchored saccharides are degraded by exogenous enzymes, resulting in eugenol release and efficient inhibition of fungal growth.

The ESCRT-III isoforms CHMP2A and CHMP2B display different effects on membranes upon polymerization

Background ESCRT-III proteins are involved in many membrane remodeling processes including multivesicular body biogenesis as first discovered in yeast. In humans, ESCRT-III CHMP2 exists as two isoforms, CHMP2A and CHMP2B, but their physical characteristics have not been compared yet. Results Here, we use a combination of techniques on biomimetic systems and purified proteins to study their affinity and effects on membranes. We establish that CHMP2B binding is enhanced in the presence of PI(4,5)P2 lipids. In contrast, CHMP2A does not display lipid specificity and requires CHMP3 for binding significantly to membranes. On the micrometer scale and at moderate bulk concentrations, CHMP2B forms a reticular structure on membranes whereas CHMP2A (+CHMP3) binds homogeneously. Thus, CHMP2A and CHMP2B unexpectedly induce different mechanical effects to membranes: CHMP2B strongly rigidifies them while CHMP2A (+CHMP3) has no significant effect. Conclusions We therefore conclude that CHMP2B and CHMP2A exhibit different mechanical properties and might thus contribute differently to the diverse ESCRT-III-catalyzed membrane remodeling processes.

Light-gated nano-porous polymersomes from stereoisomer-directed self-assemblies

Capsules with holes in the walls exist in natural systems like virus capsids, and in biomimetic systems like immune-stimulating complexes vaccines and liposomes of phospholipids/surfactants mixtures. Structuring pores into stable membrane and controlling their opening are extremely useful for applications that require nano-pores as channels for material exchange and transportation. Polymersomes, which are stable and robust vesicles made of amphiphilic block copolymer, are good candidates for drug carriers or micro/nanoreactors. Engineering structure-inherent and light-gated nano-porous polymersomes is especially appealing, but still unexplored. Here we present these polymersomes made from a polymer including a tetraphenylethene (TPE) in its center. TPE is an emblematic fluorogen with aggregation-induced emission, which possesses two stereoisomers sensitive to photoisomerization. Trans-isomer of the polymer forms classical vesicles, cis-isomer forms cylindrical micelles, while trans/cis mixtures construct perforated vesicles with nano-pores. Under UV light, the classical polymersomes of trans-isomer can be perforated by its cis-counterpart generated from the photoisomerization.