Controlled particle positioning using liquid film squeeze flow

Particles trapped in a fluid layer between a glass slide and coverslip can be moved by depressing the coverslip at one edge. This simple premise is explored as a way of making a system capable of micron accuracy particle manipulation with the fluid retained within these disposable and universally used surfaces. Piezoelectric stacks are used to depress the coverslip and the ensuing particle motion is characterised. In this work we add, to this method, a visual feedback control system to interface with four piezoelectric stacks. Through this method control of location and trajectory of 6.02 μm particles is demonstrated over distances in excess of 100 μm and with an accuracy of half the particle diameter. Such accuracy has potential for applications in moving functionalised mobile particles to static adherent cells.