Multiple Emulsion Templating of Hybrid Ag/SiO₂ Capsules for Antibacterial Applications

Abstract

Silver nanoparticles (NPs) encapsulated in amorphous silica shells are synthesized and evaluated for their antibacterial action using the Gram‐negative Escherichia coli bacterium. These inorganic capsules are synthesized using a new approach that comprises the use of oil‐in‐water‐in‐oil (O/W/O) multiple emulsions to fabricate SiO2 capsules incorporating organically capped Ag NPs. This strategy is explored as a mean to promote the bioadhesion of the microorganisms to the silica rough surfaces while still keeping the system with a high surface area for the active metal. The results have shown that the hybrid capsules enable a slow release of cationic silver from the interior of the silica microsphere to the external medium probably through the pore channels in the shell. The antibacterial activity against E. coli is mainly determined by the Ag+ ion release rate, suggesting that these particulates can be employed as a robust system for prolonged used as an antimicrobial material.

Ultrafast microfluidic synthesis of hierarchical triangular silver core-silica shell nanoplatelet toward enhanced cellular internalization

“…This can be attributed to the significantly reduced release rate of Ag + ions by the silica coating layer, which limits the accessibilities of silver ions to cells. [31] To explore the in-depth cell-particle interactions, we conjugated FITC on the particle surface of tAg@SiO 2 and sAg@SiO 2 and compared their cellular internalization efficiency. Fluorescent microscopy and flow cytometry were used to qualitatively and quantitatively measure the fluorescence intensity of cells, respectively.…”

Revisiting Current Photoactive Materials for Antimicrobial Photodynamic Therapy

“…In fact, due to their small size, MNPs can attach to the cell wall of the bacteria or fungi through self-assembly causing cell death [ 46 ]. Additionally, some metals, like silver or zinc, are known for their natural antibacterial activity [ 47 , 48 , 49 ]. However, the MNPs must have the adequate dimension in order to avoid agglomeration/aggregation phenomena, which is related with a significant reduction of the antimicrobial effect.…”

Structural Insight into Stabilization of Pickering Emulsions with Fe3O4@SiO2 Nanoparticles for Enzyme Catalysis in Organic Media

“…It has been found that enzymes often catalyze a broad variety of reactions with strong chemo‐, stereo‐, and regioselectivity properties; however, the use of organic media usually decreases the stability of free enzymes . During recent years, Pickering emulsions in high‐quality aqueous microenvironments have been widely utilized for the enzyme immobilization in organic media . For instance, Wang et al synthesized hollow polymersome‐stabilized colloidosomes for biphasic enzymatic catalysis; the obtained lipase encapsulated inside a polymersome lumen exhibited a high specific activity of 70.8 U mg −1 .…”