In vitro biocompatibility of electrospun and solvent-cast chitosan substrata towards Schwann, osteoblast, keratinocyte and fibroblast cells

Chitosan or poly(N-acetyl-d-glucosamine-co-d-glucosamine) with a degree of deacetylation of about 85% was fabricated into nanofibrous membranes by electrospinning from 7% w/v chitosan solution in 70:30 v/v trifluoroacetic acid/dichloromethane solvent system. The obtained fibers were smooth without the presence of beads. The diameters of the individual fiber segments were 126 ± 20 nm. The potential for use of the electrospun chitosan nanofibrous membranes as substrates for cell/tissue culture was evaluated with four different cell types, i.e., Schwann cells, osteoblast-like cells, keratinocytes and fibroblasts, in terms of the attachment and the proliferation of the cells as well as the morphology of the seeded and the cultured cells. The results were compared with the corresponding solvent-cast films. Both types of the chitosan substrates supported the attachment and, at the same time, promoted the largest increase in the viability of the cultured keratinocytes. The viability of Schwann cells cultured on these substrates increased marginally well, but the attachment of the cells on the surfaces was relatively poor. Finally, both types of the chitosan substrates showed cytostatic property towards both osteoblast-like cells and fibroblasts, despite the convincingly good attachment of osteoblast-like cells on the surfaces.     

Indium-mediated cleavage of diphenyl diselenide and diphenyl disulfide: efficient one-pot synthesis of unsymmetrical diorganyl selenides, sulfides, and selenoesters

A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine.