Unconventional bioprinting modalities for advanced tissue biofabrication

Bioprinting has been widely used to fabricate three-dimensional constructs for various applications. However, conventional bioprinting modalities face challenges such as low resolution, poor repeatability, limited speed, and scalability constraints. To overcome these limitations, unconventional bioprinting modalities have been actively developed, utilizing electric fields, acoustic waves, magnetic forces, light, smart materials, and microfluidics to advance bioprinted tissues. This Review explores various unconventional bioprinting modalities, which significantly improve upon conventional counterparts to create complex, scalable heterogenous tissue constructs. In addition, emerging bioprinting methods, utilizing the principles of conventional or unconventional bioprinting modalities with new concepts integrated, such as embedded bioprinting, cryobioprinting, microgravity bioprinting and 4D bioprinting, were discussed. Key applications include functional tissue engineering, disease modeling, and organoid development, with future directions focusing on artificial intelligence-driven bioprinting, multimodal biofabrication, and intraoperative bioprinting to improve scalability and clinical translation. By integrating interdisciplinary innovations, unconventional bioprinting offers new opportunities to advance tissue biofabrication technologies.