Microfluidic chip for culturing intestinal epithelial cell layers: Characterization and comparison of drug transport between dynamic and static models

Dynamic flow in vitro models are currently widely explored for their applicability in drug development research. The application of gut-on-chip models in toxicology is lagging behind. Here we report the application of a gut-on-chip model for biokinetic studies and compare the observed biokinetics of reference compounds with those obtained using a conventional static in vitro model. Intestinal epithelial Caco-2 cells were cultured on a porous membrane assembled between two glass flow chambers for the dynamic model, or on a porous membrane in a Transwell model. Confocal microscopy, lucifer yellow translocation, and alkaline phosphatase activity evaluation revealed that cells cultured in the gut-on-chip model formed tight, differentiated, polarized monolayers like in the static cultures. In the dynamic gut-on-chip model the transport of the high permeability compounds antipyrine, ketoprofen and digoxin was lower (i.e. 4.2-, 2.7- and 1.9-fold respectively) compared to the transport in the static Transwell model. The transport of the low permeability compound, amoxicillin, was similar in both the dynamic and static in vitro model. The obtained transport values of the compounds are in line with the compound Biopharmaceuticals Classification System. It is concluded that the gut-on-chip provides an adequate model for transport studies of chemicals

In situ generation of Ag nanoparticles on polyester fabrics by photoreduction using TiO2 nanoparticles

This study discusses the possibility of in situ generation of Ag nanoparticles on polyester fabric by photoreduction of Ag+ ions with deposited TiO2 nanoparticles in the presence of amino acid alanine and methyl alcohol. The presence of TiO2/Ag nanoparticles on the polyester fiber surface was confirmed by XRD, XPS, and SEM analyses. Such nanocomposite textile material provides excellent antimicrobial activity against Gram-negative bacterium E. coli, Gram-positive bacterium S. aureus, and fungus C. albicans. Maximum microbial reduction was preserved even after ten washing cycles. In spite of satisfactory laundering durability, the release of silver occurred during washing. The leaching of silver was also present when the fabrics were exposed to artificial sweat at pH 5.5 and pH 8.0 for 24 h. In addition to excellent antimicrobial properties, TiO2/Ag nanoparticles imparted maximum UV protection to polyester fabrics

In situ photoreduction of Ag+-ions by TiO2 nanoparticles deposited on cotton and cotton/PET fabrics

The possibility of in situ photoreduction of Ag+-ions using TiO2 nanoparticles deposited on cotton and cotton/PET fabrics in the presence of amino acid alanine and methyl alcohol has been discussed. The possible interaction between TiO2, alanine and Ag+-ions was evaluated by FTIR analysis. The fabrication of TiO2/Ag nanoparticles on both fabrics was confirmed by SEM, EDX, XRD, XPS and AAS analyses. Cotton and cotton/PET fabrics impregnated with TiO2/Ag nanoparticles provided maximum reduction of Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus. Although excellent antibacterial activity was preserved after ten washing cycles, a significant amount of silver leached out from the fabrics into the washing bath. The perspiration fastness assessment revealed that smaller amounts of silver were also released from the fabrics into artificial sweat at pH 5.50 and 8.00. In addition, deposited TiO2/Ag nanoparticles imparted maximum UV protection to fabrics