Conclusion

In summary, the DOME offers a versatile and low-cost platform for the engineering of microscopic collectives using light. The basic building blocks of local communication, stigmergy, and controllable motion demonstrated could be used as the basis for more complex collective behaviours. Entirely new swarm behaviours could even be engineered by combining the closed loop nature of the DOME with automatic discovery processes based on machine learning algorithms \cite{Jones_2019,cichos2020machine,Sol__2018}. The DOME’s open-source modular design makes it easy to adapt for new needs, for example, changing the light source of the projector to enable different forms of fluorescent imaging, different magnification, or adding temperature/gas control to maintain the viability of different types of cell (e.g. mammalian cells), and future extensions could even introduce magnetic, sound, or chemical inputs as additional control modalities. Beyond microswarm engineering, the DOME also offers a means to both understand and influence the collective behaviour of natural cellular populations, opening up new avenues for the study of complex systems spanning cancer to the microbiome.