Ideal Living Skin Equivalents, From Old Technologies and Models to Advanced Ones: The Prospects for an Integrated Approach.

The development of technologies for the generation and transplantation of living skin equivalents (LSEs) is a significant area of translational medicine. Such functional equivalents can be used to model and study the morphogenesis of the skin and its derivatives, to test drugs, and to improve the healing of chronic wounds, burns, and other skin injuries. The evolution of LSEs over the past 50 years has demonstrated the leap in technology and quality and the shift from classical full-thickness LSEs to principled new models, including modification of classical models and skin organoids with skin derived from human-induced pluripotent stem cells (iPSCs) (hiPSCs).

A combined solid-state H, C, O NMR and periodic DFT study of hyperfine coupling tensors in paramagnetic copper(II) compounds.

We report solid-state H, C, and O NMR determination of hyperfine coupling tensors (A-tensors) in several paramagnetic Cu(II) (d, S = 1/2) complexes: trans-Cu(DL-Ala)·HO, Cu([1-C]acetate)·HO, Cu([2-C]acetate)·HO, and Cu(acetate)·HO. Using these new experimental results and some A-tensor data available in the literature for trans-Cu(L-Ala) and KCuCl·2HO, we were able to examine the accuracy of A-tensor computation from a periodic DFT method implemented in the BAND program. We evaluated A-tensors on H (I = 1/2), C (I = 1/2), N (I = 1), O (I = 5/2), K (I = 3/2), Cl (I = 3/2), and Cu (I = 3/2) nuclei over a range spanning more than 3 orders of magnitude.

H/O Chemical Shift Waves in Carboxyl-Bridged Hydrogen Bond Networks in Organic Solids.

We report solid-state H and O NMR results for four O-labeled organic compounds each containing an extensive carboxyl-bridged hydrogen bond (CBHB) network in the crystal lattice: tetrabutylammonium hydrogen di-[O]salicylate (), [O]quinolinic acid (), [O]dinicotinic acid (), and [O]Gly/[O]Gly·HCl cocrystal (). The H isotropic chemical shifts found for protons involved in different CBHB networks are between 8.2 and 20.

Understanding Cu(i) local environments in MOFs Cu NMR spectroscopy.

The field of metal-organic frameworks (MOFs) includes a vast number of hybrid organic and inorganic porous materials with wide-ranging applications. In particular, the Cu(i) ion exhibits rich coordination chemistry in MOFs and can exist in two-, three-, and four-coordinate environments, which gives rise to many structural motifs and potential applications. Direct characterization of the structurally and chemically important Cu(i) local environments is essential for understanding the sources of specific MOF properties.

Experimental Evidence for Non-Fermi-Contact J Coupling Across Chalcogen Bonds in Ionic Salt Cocrystal Polymorphs.

A pair of novel polymorphic ionic cocrystals of 3,4-dicyanotelluradiazole and tetraphenylphosphonium bromide are synthesized and are characterized by single-crystal XRD. Strong and directional non-covalent chalcogen bonds (ChB) between Te and Br are analyzed via solid-state NMR to reveal large and anisotropic J(Te,Br) coupling tensors, providing unequivocal evidence for non-Fermi contact contributions across ChBs. Along with large Br quadrupolar couplings for the Br anions, these data provide new tools to characterize chalcogen bonds and to differentiate between ChB polymorphs.