<p>The convergence of quantum sensing and organ-on-a-chip (OoC) technologies represents an untapped frontier in biomedical diagnostics and personalised medicine. This Perspective argues that quantum biosensors such as nitrogen-vacancy (NV) centres in diamond and quantum dots offer transformative capabilities for in situ, real-time monitoring within physiologically relevant microfluidic platforms. We outline the conceptual framework for integrating these technologies, highlight emerging proof-of-concept demonstrations, and identify the engineering, biological, and translational hurdles that must be overcome. We propose a roadmap toward hybrid quantum OoC systems capable of redefining preclinical testing, adaptive therapeutics, and systems biology.</p> Graphical Abstract <p></p>