Biopolymer Composites Material Extrusion and their Applications: A Review

Advances in additive manufacturing are leading to the emergence of new printable applications, including sensors for healthcare monitoring and bioengineering scaffolds. Research is driven by designing new printable inks including composites that can be extruded and respond to changes in their surroundings and patterning these materials on the microscale. In modern printing techniques, an emerging modified three-dimensional (3D) printing method: materials extrusion has been utilized for customizable electronics because of its high compatibility with various inks, low cost, and versatility to different levels of complexity. Material extrusion enables not only the printing of 2D and 3D architecture of the electrode structure but also the bioprinting of structures such as conductive scaffolds. In this review, fundamental insights into rational printable ink formulation including colloidal suspensions, gels, polymer melts, composites, printing criteria, processes, and applications toward printable electronics using composites composed of nanomaterials and biopolymers are fully discussed. New manufacturing insights on how to further improve the resolution and simplify the printing process of responsive materials are discussed, which have not been seen in currently published representative reviews. It is envisioned that this review provides high scientific merits to readers working in wearable devices, biological smart materials, and flexible nanoelectronics. This review describes the components and practical steps to extrusion-based direct ink writing (DIW), discusses steps, printer choice, fabrication and synthesis methods of graphenic material printable inks, and results in composites and ink formulation for DIW with a focus on the use of different biopolymer matrix.image & COPY; 2023 WILEY-VCH GmbH