Graphene oxide (GO) is suggested to have great potential as a component of biomedical devices. Although this nanomaterial has been demonstrated to be cytocompatible in vitro, its compatibility in vivo in tissue sites relevant for biomedical device application is yet to be fully understood. Here, we evaluate the compatibility of GO with two different oxidation levels following implantation in subcutaneous and intraperitoneal tissue sites, which are of broad relevance for application to medical devices. We demonstrate GO to be moderately compatible in vivo in both tissue sites, with the inflammatory reaction in response to implantation consistent with a typical foreign body reaction. A reduction in the degree of GO oxidation results in faster immune cell infiltration, uptake, and clearance following both subcutaneous and peritoneal implantation. Future work toward surface modification or coating strategies could be useful to reduce the inflammatory response and improve compatibility of GO as a component of medical devices.

Scaffolds have been broadly applied within tissue engineering and regenerative medicine to regenerate, replace, or augment diseased or damaged tissue. For a scaffold to perform optimally, several design considerations must be addressed, with an eye toward the eventual form, function, and tissue site. The chemical and mechanical properties of the scaffold must be tuned to optimize the interaction with cells and surrounding tissues. For complex tissue engineering, mass transport limitations, vascularization, and host tissue integration are important considerations. As the tissue architecture to be replaced becomes more complex and hierarchical, scaffold design must also match this complexity to recapitulate a functioning tissue. We outline these design constraints and highlight creative and emerging strategies to overcome limitations and modulate scaffold properties for optimal regeneration. We also highlight some of the most advanced strategies that have seen clinical application and discuss the hurdles that must be overcome for clinical use and commercialization of tissue engineering technologies. Finally, we provide a perspective on the future of scaffolds as a functional contributor to advancing tissue engineering and regenerative medicine.

A series of soluble, thermally stable aromatic polyimides were synthesized using commercially available five and six membered ring anhydrides and 2, 6-diaminotriptycene derivatives. All of these triptycene polyimides (TPIs) were soluble in common organic solvents despite their completely aromatic structure, due to the three-dimensional triptycene structure that prevents strong interchain interactions. Low solution viscosities (0.07 to 0.47 dL/g) and versatile solubilities allow for easy solution processing of these polymers. Nanoporosity in the solid state gives rise to high surface areas (up to 430 m 2 /g) and low refractive indices (1.19-1.79 at 633 nm), which suggest very low dielectric constants at optical frequencies. Polymer films were found to be amorphous. The decomposition temperature (T d) for all of the polymers is above 500 ºC and no glass transition temperatures can be found below 450 °C by differential scanning calorimetry (DSC), indicating excellent prospects for high temperature

Current research in materials has devoted much attention to graphene, with a considerable amount of the chemical manipulation going through the oxidized state of the material, known as graphene oxide (GO). In this report, the hydroxyl functionalities in GO, the vast majority that must be allylic alcohols, are subjected to Johnson-Claisen rearrangement conditions. In these conditions, a [3,3] sigmatropic rearrangement after reaction with triethyl orthoacetate gives rise to an ester functional group, attached to the graphitic framework via a robust C-C bond. This variation of the Claisen rearrangement offers an unprecedented versatility of further functionalizations, while maintaining the desirable properties of unfunctionalized graphene. The resultant functional groups were found to withstand reductive treatments for the deoxygenation of graphene sheets and a resumption of electronic conductivity is observed.The ester groups are easily saponified to carboxylic acids in situ with basic conditions, to give water-soluble graphene. The ester functionality can be further reacted as is, or the carboxylic acid can easily be converted to the more reactive acid chloride. Subsequent amide formation yields up to 1 amide in 15 graphene carbons and increases intergallery spacing up to 12.8 Å, suggesting utility of this material in capacitors and in gas storage. Other functionalization Submitted to 22222222224222 schemes, which include the installation of terminal alkynes and dipolar cycloadditions, allow for the synthesis of a highly positively charged, water-soluble graphene. The highly negatively and positively charged graphenes (zeta potentials of -75 mV and +56 mV, respectively), have been successfully used to build layer-by-layer (LBL) constructs.