Automated and collision-free navigation of multiple micro-objects in obstacle-dense microenvironments using optoelectronic tweezers

Automated parallel manipulation of multiple micro-objects with optoelectronic tweezers (OET) has brought significant research interests recently. However, the parallel manipulation of multiple objects in complex obstacle-dense microenvironment using OET technology based on negative dielectrophoresis (nDEP) remain a big technical challenge. In this work, we proposed an adaptive light pattern design strategy to achieve automated parallel OET manipulation of multiple micro-objects and navigate them through obstacles to target positions with high precision and no collision. We first developed a multi-micro-object parallel manipulation OET system, capable of simultaneous image processing and microparticles path planning. To overcome microparticle collisions caused by overlapping light patterns, we employed a novel adaptive light pattern design that can dynamically adjust the layout of overlapping light patterns according to surrounding environment, ensuring enough space for each microparticle and preventing unintended escapes from the OET trap. The efficacy of this approach has been verified through systematic simulations and experiments. Utilizing this strategy, multiple polystyrene microparticles were autonomously navigated through obstacles and microchannels to their intended destinations, demonstrating the strategy's effectiveness and potential for automated parallel micromanipulation of multiple microparticles in complex and confined microenvironments.