From lab to life: advances inin-situbioprinting and bioink technology.

Bioprinting has the potential to revolutionize tissue engineering and regenerative medicine, offering innovative solutions for complex medical challenges and addressing unmet clinical needs. However, traditionalin vitrobioprinting techniques face significant limitations, including difficulties in fabricating and implanting scaffolds with irregular shapes, as well as limited accessibility for rapid clinical application. To overcome these challenges,in-situbioprinting has emerged as a groundbreaking approach that enables the direct deposition of cells, biomaterials, and bioactive factors onto damaged organs or tissues, eliminating the need for pre-fabricated 3D constructs. This method promises a personalized, patient-specific approach to treatment, aligning well with the principles of precision medicine. The success ofin-situbioprinting largely depends on the advancement of bioinks, which are essential for maintaining cell viability and supporting tissue development. Recent innovations in hand-held bioprinting devices and robotic arms have further enhanced the flexibility ofin-situbioprinting, making it applicable to various tissue types, such as skin, hair, muscle, bone, cartilage, and composite tissues. This review examinesin-situbioprinting techniques, the development of smart, multifunctional bioinks, and their essential properties for promoting cell viability and tissue growth. It highlights the versatility and recent advancements inin-situbioprinting methods and their applications in regenerating a wide range of tissues and organs. Furthermore, it addresses the key challenges that must be overcome for broader clinical adoption and propose strategies to advance these technologies toward mainstream medical practice.