Biomaterial-minimalistic photoactivated bioprinting of cell-dense tissues

Conventional hydrogel-based bioprinting methods often suffer from insufficient cell densities, which may limit crucial cell-cell interactions and impair overall tissue functions. Here, we present an approach that modifies cell membranes with acrylate bonds, allowing living cells at physiological densities (up to ∼10⁹ cells mL^-1) to serve directly as bioinks, demonstrating photoactivated bioprinting through digital light processing using purely cellular bioinks. Our cell-dense bioinks (CLINKs) rapidly produce tissue constructs that closely mimic native tissues, characterized by strong structural relevancy and robust functionality. The high cellularity and living nature of CLINKs enable the creation of advanced biological models such as connected neural circuits and rhythmically contracting mini-hearts derived entirely from stem cells, effectively capturing essential native-like behaviors. Implants created through this method showcase the capacity to integrate with the host, thereby promoting regeneration. Our CLINK technology holds substantial promise in tissue biofabrication, opening alternative avenues for biomedical applications.