The promising crystallinity and tunable redox capabilities of naphthalene diimides make them attractive candidates as electroactive materials for organic-based lithium-ion batteries. In this study, a family of naphthalene diimide derivates was synthesized and their redox properties explored with the intent of unveiling structures with reduction potentials that are higher than those encountered in previous organic redox processes. Changes in the electronic characteristics of the aryl substituents resulted in materials with discharge potentials that vary from 2.3 to 2.9 V vs Li/Li+, with discharge capacities as high as 121 mAh/g.

Presently, the only commercially available power generating thermoelectric (TE) modules are based on bismuth telluride (Bi2Te3) alloys and are limited to a hot side temperature of 250 °C due to the melting point of the solder interconnects and/or generally poor power generation performance above this point. For the purposes of demonstrating a TE generator or TEG with higher temperature capability, we selected skutterudite based materials to carry forward with module fabrication because these materials have adequate TE performance and are mechanically robust. We have previously reported the electrical power output for a 32 couple skutterudite TE module, a module that is type identical to ones used in a high temperature capable TEG prototype. The purpose of this previous work was to establish the expected power output of the modules as a function of varying hot and cold side temperatures. Recent upgrades to the TE module measurement system built at the Fraunhofer Institute for Physical Measurement Techniques allow for the assessment of not only the power output, as previously described, but also the thermal to electrical energy conversion efficiency. Here we report the power output and conversion efficiency of a 32 couple, high temperature skutterudite module at varying applied loading pressures and with different interface materials between the module and the heat source and sink of the test system. We demonstrate a 7% conversion efficiency at the module level when a temperature difference of 460 °C is established. Extrapolated values indicate that 7.5% is achievable when proper thermal interfaces and loading pressures are used.

Axons of the adult central nervous system exhibit an extremely limited ability to regenerate after spinal cord injury. Experimentally generated patterns of axon growth are typically disorganized and randomly oriented. Support of linear axonal growth into spinal cord lesion sites has been demonstrated using arrays of uniaxial channels, templated with agarose hydrogel, and containing genetically engineered cells that secrete brain-derived neurotrophic factor (BDNF). However, immobilizing neurotrophic factors secreting cells within a scaffold is relatively cumbersome, and alternative strategies are needed to provide sustained release of BDNF from templated agarose Correspondence to: Christina Chan, krischan@egr.msu.edu; Jeffrey Sakamoto, jsakamot@egr.msu.edu. NIH Public AccessAuthor Manuscript Adv Funct Mater. Author manuscript; available in PMC 2010 March 2. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript scaffolds. Existing methods of loading the drug or protein into hydrogels cannot provide sustained release from templated agarose hydrogels. Alternatively, here it is shown that pH-responsive Hbonded poly(ethylene glycol)(PEG)/poly(acrylic acid)(PAA)/protein hybrid layer-by-layer (LbL) thin films, when prepared over agarose, provided sustained release of protein under physiological conditions for more than four weeks. Lysozyme, a protein similar in size and isoelectric point to BDNF, is released from the multilayers on the agarose and is biologically active during the earlier time points, with decreasing activity at later time points. This is the first demonstration of monthlong sustained protein release from an agarose hydrogel, whereby the drug/protein is loaded separately from the agarose hydrogel fabrication process.

A nanocomposite hydrogel with photocrosslinkable micro-porous networks and a nanoclay component was successfully prepared to control the release of growth factor-rich stem cell secretome. The proven pro-angiogenic and cardioprotective potential of this new bioactive system provides a valuable therapeutic platform for cardiac tissue repair and regeneration.

Nanodiamonds (NDs) have attracted considerable attention as drug delivery nanocarriers due to their low cytotoxicity and facile surface functionalization. Given these features, NDs have been recently investigated for the fabrication of nanocomposite hydrogels for tissue engineering. Here we report the synthesis of a hydrogel using photocrosslinkable gelatin methacrylamide (GelMA) and NDs as a three-dimensional scaffold for drug delivery and stem cell-guided bone regeneration. We investigated the effect of different concentration of NDs on the physical and mechanical properties of the GelMA hydrogel network. The inclusion of NDs increased the network stiffness, which in turn augmented the traction forces generated by human adipose stem cells (hASCs). We also tested the ability of NDs to adsorb and modulate the release of a model drug dexamethasone (Dex) to promote the osteogenic differentiation of hASCs. The ND-Dex complexes modulated gene expression, cell area, and focal adhesion number in hASCs. Moreover, the integration of the ND-Dex complex within GelMA hydrogels allowed a higher retention of Dex over time, resulting in significantly increased alkaline phosphatase activity and calcium deposition of encapsulated hASCs. These results suggest that conventional GelMA hydrogels can be coupled with conjugated NDs to develop a novel platform for bone tissue engineering.