Biological tissues comprise a spatially complex structure, composition and organization at the microscale, named the microstructure. Given the close structure-function relationships in tissues, structural characterization is essential to fully understand the functioning of healthy and pathological tissues, as well as the impact of possible treatments. Here, we present a nondestructive imaging approach to perform quantitative 3D histo(patho)logy of biological tissues, termed Cryogenic Contrast-Enhanced MicroCT (cryo-CECT). By combining sample staining, using an X-ray contrast-enhancing staining agent, with freezing the sample at the optimal freezing rate, cryo-CECT enables 3D visualization and structural analysis of individual tissue constituents, such as muscle and collagen fibers. We applied cryo-CECT on murine hearts subjected to pressure overload following transverse aortic constriction surgery. Cryo-CECT allowed to analyze, in an unprecedented manner, the orientation and diameter of the individual muscle fibers in the entire heart, as well as the 3D localization of fibrotic regions within the myocardial layers. We foresee further applications of cryo-CECT in the optimization of tissue/food preservation and donor banking, showing that cryo-CECT also has clinical and industrial potential.

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A carbonylative route towards the synthesis of benzimidazo[2,1b]quinazolin-12-ones was developed. The key step in this strategy consists of an intramolecular carbonylative lactam formation, starting from N-(2-bromophenyl)-1H-benzimidazol-2amines. These precursor molecules were synthesized by two different methods to introduce a variety of substituents on the aromatic ring systems. Interestingly, only near-stoichiometric amounts of carbon monoxide were required in the ring-closing aminocarbonylation reaction, rendering the developed strategy also suitable for late-stage 13 C-isotopic labelling.

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