Extrusion-Based 3D Printing for Highly Porous Alginate Materials Production

Investigation of the 3D Printing Process Utilizing a Heterophase System

Direct ink writing (DIW) requires careful selection of ink composition with specific rheological properties, and it has limitations, such as the inability to create overhanging parts or branched geometries. This study presents an investigation into enhancing the 3D printing process through the use of a heterophase system, aiming to overcome these limitations. A modification was carried out in the 3D printer construction, involving adjustments to the structural elements responsible for the extrusion device's movement. Additionally, a method for obtaining a heterophase system based on gelatin microparticles was developed to enable the 3D printing process with the upgraded printer. The structure and rheological properties of the heterophase system, varying in gelatin concentration, were thoroughly examined. The material's viscosity ranged from 5.4 to 32.8 kPa·s, exhibiting thixotropic properties, pseudoplastic behavior, and long-term stability at 20 °C. The developed 3D printing technology was successfully implemented using a heterophase system based on different gelatin concentrations. The highest product quality was achieved with a heterophase system consisting of 4.5 wt.% gelatin, which exhibited a viscosity of 22.4 kPa·s, enabling the production of products without spreading or compromising geometrical integrity.

Modification, 3D printing process and application of sodium alginate based hydrogels in soft tissue engineering: A review

Sodium alginate (SA) is an inexpensive and biocompatible biomaterial with fast and gentle crosslinking that has been widely used in biological soft tissue repair/regeneration. Especially with the advent of 3D bioprinting technology, SA hydrogels have been applied more deeply in tissue engineering due to their excellent printability. Currently, the research on material modification, molding process and application of SA-based composite hydrogels has become a hot topic in tissue engineering, and a lot of fruitful results have been achieved. To better help readers have a comprehensive understanding of the development status of SA based hydrogels and their molding process in tissue engineering, in this review, we summarized SA modification methods, and provided a comparative analysis of the characteristics of various SA based hydrogels. Secondly, various molding methods of SA based hydrogels were introduced, the processing characteristics and the applications of different molding methods were analyzed and compared. Finally, the applications of SA based hydrogels in tissue engineering were reviewed, the challenges in their applications were also analyzed, and the future research directions were prospected. We believe this review is of great helpful for the researchers working in biomedical and tissue engineering.