FLUCS

Micro flow photomanipulation

With FLUCS photomanipulation, the non-invasive and flexible control of microscopic flows, we offer the microscopist a completely new tool to manipulate the sample. Active transport by fluid flows is a hallmark of many living microscopic systems, and the ability to actively control intracellular motion can add an entirely new dimension to life science research.

Cooperation

The FLUCS photomanipulation system for microscopic flows has been developed based on a close scientific cooperation with Moritz Kreysing and his research group at the Max-Planck-Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden, Germany. Patents pending.

Thermo-viscous flow

By moderately heating the specimen with a rapidly scanned infrared laser spot, directed fluid flows are induced. By flexibly designing the scan path of the laser, fluid is pumped along prespecified paths in the focal plane of a microscope. For optimal performance in aqueous solutions, the wave length of the IR laser is optimized for the absorption spectrum of water.

Flow specifications

Variable	Unit	Min	Typical	Max
Flow velocity U	µm/s	0	10	100
Specimen thickness d	µm	5	30	200
Temperature increase ΔT	K	0	5	50
Spatial extent of flow pattern L	µm	5	30	200

Variable	Unit	Min	Typical	Max
Flow velocity U	“µm/s”	0	10	100
Specimen thickness d	µm	5	30	200
Temperature increase ΔT	K	0	5	50
Spatial extent of flow pattern L	µm	5	30	200

Basic and compound flow patterns

Flow patterns are directly defined in the current camera image. The speed of the flow is controlled by adjusting laser power and scan frequency. Temporal control has microsecond accuracy and can be embedded in complex experimental protocols.

Applications

Cell biology

Cytoplasmatic streaming: Invert PAR domains in c. elegans embryo
Local rheology measurement in cell
Probe material properties of centrosomes with flow perturbations
Hydrodynamic trapping and force measurement
Localized temperature gradients

Biophysics

Intra-cellular transport through advective micro flows, reaction-advection-diffusion systems
Hydrodynamic trapping of cells, colloids, or particles

Microfluidics

Flow pumping in micro channels
Efficient micro-mixer, time-dependent flow
Droplet based micro fluidics
Sorting and selecting of colloids, cells or droplets

Medical research

Sorting and handling of individual cells

Videos

Microscale flows

Rotation of PAR domain in C. elegans embryo (Courtesy of Kreysing Lab, cf. Mittasch et al.(2018))

Deformation and rupture of centrosome in C.elegans embryo (Courtesy of Kreysing Lab, cf. Mittasch et al.(2020))

Cytoplasmatic streaming in Elodea cells

Flow-induced rotation of chromatin inside the nucleus in C. elegans embryo (Courtesy of Kreysing Lab)

REFERENCES

I.D. Stoev, B. Seelbinder, E. Erben, N. Maghelli, M. Kreysing (2021): Highly sensitive force measurements in an optically generated, harmonic hydrodynamic trap, eLight 1:7. https://doi.org/10.1186/s43593-021-00007-7
E. Erben, B. Seelbinder, I.D. Stoev, S. Klykov, N. Maghelli, M. Kreysing (2021): Feedback-based positioning and diffusion suppression of particles via optical control of thermoviscous flows, Optics Exp., Vol. 29, No. 19, 30272. https://doi.org/10.1364/OE.432935
N.T. Chartier, A. Mukherjee, J. Pfanzelter, S. Fürthauer, B.T. Larson, A.W. Fritsch, R. Amini, M. Kreysing, F. Jülicher, S.W. Grill (2021): A hydraulic instability drives the cell death decision in the nematode germline, Nat. Physics, Vol 17, 920-925. https://doi.org/10.1038/s41567-021-01235-x
M. Mittasch, V.M. Tran, M.U. Rios, A.W. Fritsch, S.J. Enos, B. Ferreira Gomez, A. Bond, M. Kreysing, J.B. Woodruff (2020): Regulated changes in material properties underlie centrosome disassembly during mitotic exit, J. Cell Biol., Vol 219(4). https://doi.org/10.1083/jcb.201912036
M. Kreysing (2019): Probing the Functional Role of Physical Motion in Development, Dev. Cell 51. https://doi.org/10.1016/j.devcel.2019.10.002
M. Mittasch, P. Gross, M. Nestler, A.W. Fritsch, C. Isermann, M. Kar, M. Munder, A. Voigt, S. Alberti, S.W. Grill, M Kreysing (2018): Non-invasive perturbations of intracellular flow reveal physical principles of cell organization, Nat. Cell Biology. https://doi.org/10.1038/s41556-017-0032-9