New Fluorine-Containing Diamine Monomers for Potentially Improved Polyimides.

Two new fluorine-containing diamine monomers were designed with the goal of reducing charge transfer complex (CTC) interactions between neighboring chains in polyimides (i.e., high transparency/low color) while hopefully maintaining the well-known thermal stability and flexibility generally associated with polyimides. The proposed diamines have been prepared through (1) the functionalization of 1,3-bis[(pentafluorobenzyl)oxy]benzene with 4-aminophenol and (2) the addition of 2-chloro-5-nitrobenzotrifluoride to 4,4'-bicyclohexanol followed by reduction of the resulting dinitro compound. The new compounds have been characterized by multinuclear NMR and IR spectroscopy and high-resolution liquid chromatography-mass spectrometry as well as single-crystal X-ray diffraction on the new diamine prepared from 4,4'-bicyclohexanol. Not only was the structure of the proposed new diamine confirmed, but another interesting example of hydrogen bonding between an N-H proton and the π-system of an aromatic ring was observed and documented. Initial polymerizations have been carried out via the two-step imidization process.

Synthetic peptide-acrylate surfaces for long-term self-renewal and cardiomyocyte differentiation of human embryonic stem cells.

Human embryonic stem cells (hESCs) have two properties of interest for the development of cell therapies: self-renewal and the potential to differentiate into all major lineages of somatic cells in the human body. Widespread clinical application of hESC-derived cells will require culture methods that are low-cost, robust, scalable and use chemically defined raw materials. Here we describe synthetic peptide-acrylate surfaces (PAS) that support self-renewal of hESCs in chemically defined, xeno-free medium. H1 and H7 hESCs were successfully maintained on PAS for over ten passages. Cell morphology and phenotypic marker expression were similar for cells cultured on PAS or Matrigel. Cells on PAS retained normal karyotype and pluripotency and were able to differentiate to functional cardiomyocytes on PAS. Finally, PAS were scaled up to large culture-vessel formats. Synthetic, xeno-free, scalable surfaces that support the self-renewal and differentiation of hESCs will be useful for both research purposes and development of cell therapies.