Limitations in wound management have prompted scientists to introduce bioprinting techniques for creating constructs that can address clinical problems. The bioprinting approach is renowned for its ability to spatially control the three-dimensional (3D) placement of cells, molecules, and biomaterials. These features provide new possibilities to enhance homology to native skin and improve functional outcomes. However, for the clinical value, the development of hydrogel bioink with refined printability and bioactive properties is needed. In this study, we combined the outstanding viscoelastic behavior of nanofibrillated cellulose (NFC) with the fast cross-linking ability of alginate (ALG), carboxymethyl cellulose (CMC), and encapsulated human-derived skin fibroblasts (hSF) to create a bioink for the 3D bioprinting of a dermis layer. The shear thinning behavior of hSF-laden bioink enables construction of 3D scaffolds with high cell density and homogeneous cell distribution. The obtained results demonstrated that hSF-laden bioink supports cellular activity of hSF (up to 29 days) while offering proper printability in a biologically relevant 3D environment, making it a promising tool for skin tissue engineering and drug testing applications.

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The present work describes novel polymer-based nanocomposite anion-exchange membranes (AEMs) with improved features for direct alkaline fuel cell applications. AEMs based on chitosan (CS), magnesium hydroxide (Mg(OH) 2), and graphene oxide (GO) with benzyltrimethylammonium chloride (BTMAC) as the hydroxide conductor were fabricated by a solvent casting method. To impart better mechanical properties and suppressed swelling, the enzymatic cross-linking with dodecyl 3,4,5-trihydroxybenzoate having C-10 alkyl chain was employed. The structure and surface morphology, KOH uptake and swelling ratio, ethanol permeability, mechanical property, ionic conductivity, cell performance, and stability of AEMs were investigated. The as-obtained AEMs showed improved hydroxide conductivity compared with previously reported CS AEMs. The highest value for hydroxide conductivity, 142.5 ± 4.0 mS cm −1 at 40°C, was achieved for the CS + Mg(OH) 2 + GO + BTMAC AEMs with an ethanol permeability value of 6.17 × 10 −7 ± 1.17 × 10 −7 cm 2 s −1 in spite of its relative high KOH uptake (1.43 g KOH/g membrane). The highest peak power density value of 72.7 mW cm −2 was obtained at 209 mA cm −2 when the pristine CS + Mg(OH) 2 AEM was used as the polymer electrolyte membrane in the direct alkaline ethanol fuel cell at 80°C. This is the highest reported power density value for CSbased membranes.

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3D printing of bio‐based nanomaterials into complex structures with design flexibility, structural anisotropy, and long‐term stability is a key issue for biomedical applications. Herein, 3D‐printed and ionically crosslinked structures with anisotropic, water‐proof, and tunable mechanical properties are fabricated using a polysaccharide ink composed of nanocellulose, alginate, and CaCO3 nanoparticles. The excellent shear thinning properties of the ink, combined with double or even triple extrusion, allow printing of complex structures (tubes, buckets, ears, and boat models) with high shape fidelity even after crosslinking. The anisotropically printed and crosslinked structures can be mechanically tuned by controlling the fiber orientation via the printing path, the amount of crosslinker, the type of acid used for crosslinking (weak to strong), and the storage medium. This allows for tailored flexibility and a tensile modulus of the materials in wet state ranging from 1 to 30 MPa. Application of hydrostatic pressure of 160–600 mmHg for 24 h with a physiological fluid to a tubular structure, a model for the cardiovascular system, shows no leakage or rupture in the tube. The great design freedom offered by 3D printing and spatially controlled structural anisotropy enable the production of tailored materials for soft robotics or biomedical applications.