Three tetrahedral organic cages have been obtained by condensing a triamino linker with a set of three ostensibly analogous triformyl precursors. Despite the large number of imine bonds formed, the corresponding cages were obtained in exceptionally high yields. Both theory and experimental results demonstrate that intramolecular CH⋅⋅⋅π interactions within all of the cage frameworks play an important role in abetting the condensations and contributing to the near-quantitative synthetic yields. The three cages of this study exhibit high thermodynamic and kinetic stability. A variety of small neutral guest molecules with complementary sizes and geometries may be used as templates in the cage forming reactions. Among the guests that may be used in this way is white phosphorus (P ), whose inherent reactivity towards oxygen is almost fully attenuated when bound within one of the cages.

Surface functionality is an essential component for processing and application of metal-organic frameworks (MOFs). A simple and cost-effective strategy for DNA-mediated surface engineering of zirconium-based nanoscale MOFs (NMOFs) is presented, capable of endowing them with specific molecular recognition properties and thus expanding their potential for applications in nanotechnology and biotechnology. It is shown that efficient immobilization of functional DNA on NMOFs can be achieved via surface coordination chemistry. With this strategy, it is demonstrated that such porphyrin-based NMOFs can be modified with a DNA aptamer for targeting specific cancer cells. Furthermore, the DNA-NMOFs can facilitate the delivery of therapeutic DNA (e.g., CpG) into cells for efficient recognition of endosomal Toll-like receptor 9 and subsequent enhanced immunostimulatory activity in vitro and in vivo. No apparent toxicity is observed with systemic delivery of the DNA-NMOFs in vivo. Overall, these results suggest that the strategy allows for surface functionalization of MOFs with different functional DNAs, extending the use of these materials to diverse applications in biosensor, bioimaging, and nanomedicine.

Graphene oxides (GOs) are layered carbon materials composed of a mixture of oxygenated functional groups that can react with different molecules. Alkyl diamine molecules (ethylenediamine, butanediamine, or hexanediamine) can insert into the layers of GO and systematically expand its interlayer spacing from 0.762 nm to over 1.030 nm. In this work, we found that CO 2 uptake maximizes at the interlayer spacing of 0.860 nm in GOs cross-linked by diamines. We characterized the subtle chemical and compositional differences among samples by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state NMR. In situ 13 C NMR was applied at variable temperatures to investigate the adsorption mechanisms of CO 2 , which revealed both physically and chemically adsorbed CO 2 in diamine-cross-linked GO matrices. In particular, we observed the unique state of CO 2 that are physically trapped in GO layers with 0.860 nm spacing by van der Waals interactions. This state of CO 2 was not observed in GOs with either smaller or larger interlayer spacings.

Ischemic lesions could lead to secondary degeneration in remote regions of the brain. However, the spatial distribution of secondary degeneration along with its role in functional deficits is not well understood. In this study, we explored the spatial and connectivity properties of white matter (WM) secondary degeneration in a focal unilateral sensorimotor cortical ischemia rat model, using advanced microstructure imaging on a 14 T MRI system. Significant axonal degeneration was observed in the ipsilateral external capsule and even remote regions including the contralesional external capsule and corpus callosum. Further fiber tractography analysis revealed that only fibers having direct axonal connections with the primary lesion exhibited a significant degeneration. These results suggest that focal ischemic lesions may induce remote WM degeneration, but limited to fibers tied to the primary lesion. These “direct” fibers mainly represent perilesional, interhemispheric, and subcortical axonal connections. At last, we found that primary lesion volume might be the determining factor of motor function deficits.

Three tetrahedral organic cages have been obtained by condensing at riamino linker with as et of three ostensibly analogous triformyl precursors.D espite the large number of imine bonds formed, the corresponding cages were obtained in exceptionally high yields.Both theory and experimental results demonstrate that intramolecular CH···p interactions within all of the cage frameworks play an important role in abetting the condensations and contributing to the near-quantitative synthetic yields.T he three cages of this study exhibit high thermodynamic and kinetic stability.Avariety of small neutral guest molecules with complementary sizes and geometries may be used as templates in the cage forming reactions.Among the guests that may be used in this way is white phosphorus (P 4 ), whose inherent reactivity towards oxygen is almost fully attenuated when bound within one of the cages.