Optical micro manipulation of live cells has been extensively used to study a wide
range of cellular phenomena with relevance in basic research or in diagnostics. The
approaches span from manipulation of many cells for high throughput measurement or
sorting, to more elaborated studies of intracellular events on trapped single cells
when coupled with modern imaging techniques. In case of direct cell trapping the damaging
effects of light-cell interaction must be minimized, for instance with the choice
of proper laser wavelength. Microbeads have already been used for trapping cells indirectly
thereby reducing the irradiation damage and increasing trapping efficiency with their
high refractive index contrast. We show here that such intermediate objects can be
tailor-made for indirect cell trapping to further increase cell-to-focal spot distance
while maintaining their free and fast maneuverability. Carefully designed structures
were produced with two-photon polymerization with shapes optimized for effective manipulation
and cell attachment. Functionalization of the microstructures is also presented that
enables cell attachment to them within a few seconds with strength much higher that
the optical forces. Fast cell actuation in 6 degrees of freedom is demonstrated with
the outlook to possible applications in cell imaging.
