Advances in In Situ Bioprinting: A Focus on Extrusion and Inkjet-Based Bioprinting Techniques

Abstract Purpose This review addresses the different techniques and applications of in situ bioprinters, considering how the advent of these in situ bioprinters is a guiding light for regenerative medicine science. Methods 3D bioprinting or additive manufacturing (AM) technology provides an innovative aspect of research in many areas, including bioengineering and medicine. A significant ground-breaking achievement in three-dimensional bioprinting is the in situ bioprinters, which directly deposit the bio-inks or bio-gels into the affected site. Results The capability to deposit bio-inks in situ is an emerging innovation in biomedical engineering. The in situ bioprinter facilitates controlled and precise bio-fabrication of multi-component systems with a wide range of shapes and material compositions. Robot-assisted or handheld bioprinters can do in situ bioprinting. A handheld bioprinter is a manually operated, easy-to-use printing device intended to accurately deposit bio-inks (biomaterials, scaffolds, and living tissues) onto target injury sites. The review sheds light on applying an in situ bioprinter for depositing cells directly to a wound, replacing damaged tissues with bio-ink-laden cells to treat an injured site. Conclusion In situ bioprinting, including portable handheld and robotic bioprinters, offers a promising approach for treating tissue damage, organ repair, and drug delivery by directly depositing bio-inks into critical tissue defects. Handheld bioprinting is particularly valuable for patients with restricted mobility, such as those with severe burns. While drop-on-demand methods offer precision, extrusion-based methods are better suited for large models and viscous bio-inks, with robotic bioprinters often combining both approaches. Lay Summary In situ bioprinting is a new technology that prints living cells onto injuries or wounds, offering new possibilities for tissue repair and regeneration. Doctors can use this technology to deposit “bio-inks” to heal damaged tissues, treat wounds, or deliver medicines using handheld or robotic devices. This approach is especially beneficial for burn victims and others with severe injuries, as it allows for personalised and immediate treatment, bringing regenerative medicine closer to real-world applications. Graphical Abstract