Here we report on the modular synthesis and characterization of biodegradable, controlled porous, liquid crystal elastomers (LCE) and their use as three-dimensional cell culture scaffolds. The elastomers were prepared by cross-linking of star block-co-polymers with pendant cholesterol units resulting in the formation of smectic-A LCEs as determined by polarized optical microscopy, DSC, and X-ray diffraction. Scanning electron microscopy revealed the porosity of the as-prepared biocompatible LCEs, making them suitable as 3D cell culture scaffolds. Biodegradability studies in physiological buffers at varying pH show that these scaffolds are intact for about 11 weeks after which degradation sets in at an exponential rate. Initial results from cell culture studies indicate that these smectic LCEs are compatible with growth, survival, and expansion of cultured neuroblastomas and myoblasts when grown on the LCEs for extended time periods (about a month). These preliminary cell studies focused on characterizing the elastomer-based scaffolds' biocompatibility and the successful 3D incorporation as well as growth of cells in 60 to 150-μm thick elastomer sheets.

Back Cover: Liquid crystal elastomers (LCE) for the use as three‐dimensional cell culture scaffolds are prepared by E. Hegmann and co‐workers by cross‐linking of star blockco‐polymers with pendant cholesterol units resulting in the formation of smectic‐A LCEs. http://doi.wiley.com/10.1002/mabi.201400325 these biodegradable materials prove to be compatible with growth, survival, and expansion of cultured neuroblastomas and myoblasts for extended time periods (about a month) and are also excellent candidates for testing on several other cell lines.

3D biodegradable and highly regular foamlike cell scaffolds based on biocompatible side-chain liquid crystal elastomers have been prepared. Scaffolds with a primary porosity characterized by spatially interlaced, interconnected microchannels or an additional secondary porosity featuring interconnected microchannel networks define the novel elastomeric scaffolds. The macroscale morphology of the dual porosity 3D scaffold resembles vascular networks observed in tissue. 3D elastomer foams show four times higher cell proliferation capability compared to conventional porous templated films and within the channels guide spontaneous cell alignment enabling the possibility of tissue construct fabrication toward more clinically complex environments.

No abstract

No abstract

Keywords: Lithiation / Ligand design / Schiff bases / Imines / Coordination polymer ortho-Metallated imines are commonly used as ligands for late transition metals. Unfortunately, not all metals, such as titanium, zirconium, and niobium, can undergo the necessary oxidative addition reactions to form the desired ortho-metallated complexes directly. Therefore, a synthetic methodology allowing easy access to this binding mode from simple early transition metal halides via an ortho-lithiated imine precursor is desirable. ortho-Lithiation of benzylamines and other systems has been well studied; in contrast, that of imines is poorly developed. However, inclusion of a 3,4-methylenedioxy group on phenyl imines allows for straightforward lithiation and simple isolation of the ortho-lithiated imines. NMR spectroscopy and single-crystal X-ray diffraction allowed for the structural elucidation of the clustering in these lithium complexes. It has been determined that the nature of the im-

No abstract

A series of niobium and tantalum imido complexes with mono-anionic ortho-metallated acetophenone imine ligands have been prepared and characterized using NMR spectroscopy, mass spectrometry and elemental analysis. These low symmetry complexes are produced with only one or two structural isomers in all cases and display interesting correlations between the steric bulk of the ligands employed and the isomers formed. Crystal structures of several new niobium and tantalum complexes are presented as confirmation of the connectivity in these structural isomers.