Using blinking optical tweezers to study cell rheology during initial cell-particle contact.

Phagocytosis is an important part of innate immunity and describes the engulfment of bacteria and other extracellular objects on the micrometer scale. The protrusion of the cell membrane around the bacteria during this process is driven by a reorganization of the actin cortex. The process has been studied on the molecular level to great extent during the past decades.

Dynamic multiple-beam counter-propagating optical traps using optical phase-conjugation.

Counter-propagating optical traps are widely used where long working distances, axially symmetric trapping potentials, or standing light waves are required. We demonstrate that optical phase-conjugation can automatically provide a counter-propagating replica of a wide range of incident light fields in an optical trapping configuration. The resulting counter-propagating traps are self-adjusting and adapt dynamically to changes of the input light field.