Utilizing the Natural Composition of Brown Seaweed for the Preparation of Hybrid Ink for 3D Printing of Hydrogels

Abstract

This study aims to utilize the natural composition of brown seaweed by deriving alginate and cellulose concurrently from the stipe (stem-like) and blade (leaf-like) structures of the seaweed; further, this is followed by fibrillation for the direct and resource-efficient preparation of alginate/cellulose nanofiber (CNF) hybrid inks for three-dimensional (3D) printing of hydrogels. The efficiency of the fibrillation process was evaluated, and the obtained gels were further studied with regard to their rheological behavior. As a proof of concept, the inks were 3D printed into discs, followed by cross-linking with CaCl 2 to form biomimetic hydrogels. It was shown that the nanofibrillation process from both seaweed structures is very energy-efficient, with an energy demand lower than 1.5 kW h/kg, and with CNF dimensions below 15 nm. The inks displayed excellent shear-thinning behavior and cytocompatibility and were successfully printed into 3D discs that, after cross-linking, exhibited an interconnected network structure with favorable mechanical properties, and a cell viability of 71%. The designed 3D biomimetic hydrogels offers an environmentally benign, cost-efficient, and biocompatible material platform with a favorable structure for the development of biomedical devices, such as 3D bio printing of soft tissues.

Solvent Mediating the in Situ Self-Assembly of Polysaccharides for 3D Printing Biomimetic Tissue Scaffolds

“…Moreover, the resulting cellulose, chitin and chitosan scaffolds exhibited high strengths of 0.68, 0.84, and 0.46 MPa (Figure l,m) at an 80% strain and Young’s modulus of 93.8, 120.9, and 48 kPa (Figure m), respectively, indicating the high structure integration and strong interaction among the filaments. Noticeably, most of the 3D-printed natural polymeric hydrogel strengths were usually less than 0.2 MPa. ,− Cyclic compression tests revealed that the scaffolds were elastic, which allowed the constructs to resist multiple compression deformations and retain their original hierarchical structures during applications (Figure n,o,p,q). Furthermore, the FS nanoparticles as a sacrificial carrier material could be almost completely removed by immersing the scaffolds in 5 wt % NaOH solution for 4 h without defecting the nanofibrous structure (Figure S19) for diverse applications.…”

Seaweed-Derived Alginate–Cellulose Nanofiber Aerogel for Insulation Applications

“…After purification, the fibrillation process resulted in the separation of the cellulosic part into very fine nanofibers through the shearing forces applied to the sample by ultrafine grinding, resulting in a gel composed of alginate and CNFs ( Figure 1 c). The characterization of the gel structure was reported in our previous study, 23 and the gel composition is summarized in the Materials section. The ACNF gel was then ice-templated and freeze-dried to form an anisotropic ACNF aerogel structure ( Figure 1 d) and treated with solutions of CaCl 2 in ethanol to generate a crosslinked sample (ACNF-X) ( Figure 1 e,f).…”

“…Furthermore, the measured energy consumption for their mechanical separation process is remarkably low (1.0 kW h kg –1 ); meanwhile, the commercially bleached wood kraft pulp consume 8.4 kW h kg –1 for a similar mechanical processing. 23 In a previous study, we have systematically evaluated the approach of direct bleaching, followed by mechanical separation of industrial residue. 54 This resulted in a reduced environmental impact of more than 75% for carbon footprint, along with a cost reduction of more than 50%, owing to an increased yield and reduced energy, chemical, and water use.…”

“…The alginate content of the purified material was 46 ± 11 wt %, and the cellulose content was 23 ± 3 wt %. 23 Optical microscopy was carried out on a Nikon Eclipse LV 100 Pol (Kanagawa, Japan) to study the morphology of the structure after purification.…”

“…The fibrillation process and characterization of the nanofibers were described in detail in our previous study. 23 After the fibrillation process, the alginate-CNFs (ACNFs) were visualized using a field-emission scanning electron microscope (FEI Magellan 400 XHR-SEM; Hillsboro, OR, USA) at 5 kV. Prior to analysis, the nanofiber samples were coated with platinum using a sputter coater (Leica EM ACE220, Wetzlar, Germany) to avoid charging effects.…”