Additive-free 3D-printed nanostructured carboxymethyl cellulose aerogels

3D printing of polysaccharide solutions is widely recognized as a highly promising method in the biomedical field for achieving complex customized shapes. One of the main challenges is in selecting conditions, in particular, the rheological properties of the system, to retain the printed shape. For the first time, the direct ink writing (DIW) is successfully applied to neat carboxymethyl cellulose (CMC) solutions without any additives or crosslinking, only by adjusting solutions' rheological properties. The influence of CMC molecular weight, degree of substitution and polymer concentration on solutions' viscoelastic properties is investigated. Extrusion velocity at various pressures and pressure calibration curves are determined to optimize printing parameters. Lightweight and nanostructured materials, aerogels, are then made from the printed structures through drying with supercritical CO₂. 3D printed aerogels with high shape stability are of density (solid part) around 0.1 g/cm³ and specific surface area up to 140 m²/g, density being twice lower and surface area twice higher than those of the "bulk" (or moulded) counterparts. Customized aerogels with high specific surface area hold significant potential in biomedical applications, such as tissue engineering, wound dressings, drug delivery, etc.