Novel Honeycomb Nanoclay Frameworks With Hemostatic and Antibacterial Properties.

Our laboratory recently developed a new class of high surface area, honeycomb Nanoclay Microsphere Framework absorbents (NMFs) that prompt rapid hemostasis. In the present work, we propose a novel approach to develop antibacterial Topical Hemostatic Agents (THAs) by anchoring silver nanoparticles (AgNPs) onto NMFs. This combination was obtained by a chemical co-reduction approach, followed by freeze-processing, and was shown to ensure stability and on-site delivery of AgNPs, without altering the hemostatic properties of NMFs. Silver-loaded NMFs showed no change in their unique architecture and led to a 55% increase in clot strength, compared to standard control plasma or commercially available THA, and a significant decrease in mean fibrin fiber diameter. Silver nanoparticles were successfully released when solubilized and prevented the growth of both Pseudomonas aeruginosa and Staphylococcus aureus at concentrations of 22 and 30 ppm of silver released, respectively. Overall, cell mortality was between 9.1 ± 5.1% and 6.3 ± 3.2%, depending on AgNP concentration, confirming a low cytotoxicity. Silver-loaded nanoclay microsphere frameworks appear to constitute promising candidates as topical hemostatic agents for secondary management of hemostasis when infection control is needed.

Metal nanoparticles inside microgel/clay nanohybrids: Synthesis, characterization and catalytic efficiency in cross-coupling reactions.

HYPOTHESIS: Laponite nanoclay embedded inside soluble crosslinked copolymers (microgels) may act as cation exchanger allowing loading of the microgels with cationic metal precursors, which upon reduction yield tailored ternary colloidal nanocomposites comprising both nanoclay and metal nanoparticles. EXPERIMENTS: Microgel nanohybrids with variable Laponite nanoclay content were loaded with cationic precursors of different noble metals (Pd, Pt, Au); subsequent reduction by several methods yielded ternary nanocomposites which were extensively characterized. Nanocomposites based on Pd were also tested as catalysts in standard Suzuki and Sonogashira cross-coupling reactions. FINDINGS: The proposed method for the production of ternary nanocomposite microgels has been validated. The factors influencing the final metal nanoparticle size (nature of the reducing agent, clay content in the microgel) have been determined and rationalized. The resulting Pd-containing ternary nanocomposite microgels are viable catalysts of standard cross coupling reactions in water-rich medium.