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Treating conic tetra-para-ethylacetato-calix[4]arene (1) with 2.2 equivalents of K2CO3 and 4 equivalents of 6-bromomethyl-6′-methyl-2,2′-bipyridine affords the expected fully substituted podand, mainly in its 1,3-alternate conformation (2). This tube-like bipyridyl derivative 2 was subjected to complexation studies with CoCl2·6H2O to give a blue tetra cobalt(II) complex species (3). This complex displays a unique group of 6 aromatic bipyridyl 1H-NMR resonance signals demonstrating its high symmetry, while X-ray diffraction studies showed the presence of 3 expected tetrahedral bpy(CoCl2) units and 1 original trigonal bipyramidal unit involving the adjunction of a fifth ligand assumed to be H2O that could participate in the crystal scaffold. [ABSTRACT FROM AUTHOR]

Bioprinting has enabled the creation of intricate scaffolds that replicate the physical, chemical, and structural characteristics of natural tissues. Recently, hydrogels have been used to fabricate such scaffolds for several biomedical applications and tissue engineering. However, the small pore size of conventional hydrogels impedes cellular migration into and remodeling of scaffolds, diminishing their regenerative potential. Porous scaffolds have been utilized for their improved diffusion of nutrients, dissolved oxygen, and waste products. However, traditional methods of generating porous structures require multiple processing steps, making them incompatible with bioprinting. Recently, we developed a method to generate multi-scale porous structures by foaming hydrogel precursors prior to printing to form colloidal bioinks. Here, to further improve the biological, mechanical, and physical properties, we functionalize colloidal bioinks with nanoliposomes (NLs), one of the most promising methods for bioactive delivery. We assess the impact of the concentration of NL on the characteristics of bioinks made from gelatin methacryloyl (GelMA) and their resulting scaffolds. Anionic liposomes made from rapeseed lecithin of 110 nm were synthesized and found to be stable over several weeks. Increasing concentrations of NL decreased the zeta potential and increased the viscosity of foamed bioinks, improving their rheological properties for printing. Furthermore, the incorporation of NL allowed for precise adjustment of the macropore size and bulk mechanical properties without any chemical interaction or impact on photocrosslinking. The nanofunctionalized foam bioinks, composed exclusively of natural components, demonstrated significant antioxidant activity and were printed into multilayered scaffolds with high printability. The foam-embedded NL showed remarkable biocompatibility with myoblasts, and cell-laden bioinks were able to be successfully bioprinted. Due to their high biocompatibility, tunable mechanical properties, printability, and antioxidant behavior, the nanofunctionalized porous scaffolds have promise for a variety of biomedical applications, including those that require precise delivery of therapeutic substances and tissue engineering., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)