This study presents a new method for the preparation of organogels embedded with interconnected macropores tunable in size from 180 to 700 μm. The gels are molded in porous polyvinyl alcohol (PVOH) polymer templates obtained from melt‐processed cocontinuous blends of PVOH and poly(ε‐caprolactone) (PCL). The blends are subsequently annealed under quiescent conditions to let their morphology coarsen, and are rendered porous by selectively extracting the PCL. After the injection in the PVOH molds and in situ gelling of a dilute solution of an organic liquid and a low molecular weight gelling agent, 12‐hydroxyoctadecanoic acid, the molds are extracted with water. This yields porous organogels with microstructural features corresponding relatively well to those of the original molds, as revealed by X‐ray microtomography. This method allows control over the gels' average pore size, pore interconnectivity, and volume fraction, and is compatible with a variety of organic liquids and low molecular weight gelators.

Biofilms represent the dominant microbial lifestyle in nature. These complex microbial communities in which bacteria are embedded in a self-produced protective polymeric extracellular matrix, display an enhanced resistance to antimicrobials and thus represent a major health challenge. Although nanoparticles have proven to be effective against bacteria, the interactions between nanoparticles and the polymeric biofilm matrix are still unclear. In this work, silver nanoparticles (AgNPs) were used on mature biofilms formed by the pathogen Vibrio cholerae, and their effects on the biofilm microstructure were evaluated. Bacteria cells within mature biofilms showed an increased tolerance to AgNPs, with their elimination requiring a concentration nine times higher than planktonic cells. Mutant strains not able to form a pellicle biofilm were four times more susceptible to AgNPs than the wild-type strain forming a strong biofilm. Moreover, electron microscopy analysis revealed that AgNPs interacted with the extracellular matrix components and disrupted its microstructure. Finally, two major proteins, Bap1 and RbmA, appeared to mediate the biofilm bacterial resistance to AgNPs. This work highlights the role of the polymeric biofilm matrix composition in resistance to AgNPs. It underlines how crucial it is to understand and characterize the interactions between nanoparticles and the biofilm matrix, in order to design appropriate metallic nanoparticles efficient against bacterial biofilms.

This article presents an approach to precisely control the localization of nanoparticles in hydrogels via interfacial synthesis with a co-solvent.

Herein, we report a novel method to synthesize metal nanoparticle-shells (NP-shells) and continuous shells at the liquid/liquid interface, via an interfacial reaction in an Ouzo emulsion. Ouzo emulsions spontaneously form...