Biophysical Tools

Our research requires the usage and development of new biophysical tools to investigate the behavior of single living cells. We are using recent advances in photonics and material sciences to stimulate cells mechanically and biochemically and to quantify their mechanical and biochemical response. Holographic optical tweezers for example allow the simultaneous manipulation of multiple functionalized colloidal particles.

Supported by our research in theoretical optics, we are trying to push the limits of optical trapping and tracking. Other components of our biophysical toolbox are magnetic twisting cytometry, digital image processing including rotational and positional particle tracking as well as biophysical modeling and simulation.

Publication demonstrating simultaneous measurement of elastic modulus and poisson number

W. Gross, H. Kress
Simultaneous measurement of the Young’s Modulus and the Poisson Ratio of thin elastic layers
Soft Matter, 13 (5), (2017), 1048-1055
DOI: 10.1039/C6SM02470J

Publication introducing optical pushing for parallelized biomolecule investigation

G. Sitters, N. Laurens, E. J. de Rijk, H. Kress, E. J. G. Peterman, G. J. L. Wuite
Optical Pushing: A Tool for Parallelized Biomolecule Manipulation
Biophys. J., 110 (1), (2016), 44-50
DOI: 10.1016/j.bpj.2015.11.028

Publication introducing Euler angle tracking of mag­ne­ti­cal­ly actuated particles

M. Irmscher, A. M. de Jong, H. Kress*, M. W. J. Prins*
Probing the Cell Membrane by Magnetic Particle Actuation and Euler Angle Tracking
Biophys. J., 102 (3), (2012), 698-708
* Joint corresponding authorship
DOI: 10.1016/j.bpj.2011.12.054

Publication introducing optically manipulated microsources

H. Kress, J-G. Park, C. O. Mejean, J. D. Forster, J. Park, S. S. Walse, Y. Zhang, D. Wu, O. D. Weiner, T. M. Fahmy, E. R. Dufresne
Cell stimulation with optically manipulated microsources
Nature Methods, 6 (12), (2009), 905-909
• Featured in optics & photonics focus, (9), Story 6 (2010), Link
DOI: 10.1038/nmeth.1400

Publications with biophysical modeling

J. Colombelli, A. Besser, H. Kress, E.G. Reynaud, P. Girard, E. Caussinus, U. Haselmann, J.V. Small, U.S. Schwarz, E.H.K. Stelzer
Mechanosensing in actin stress fibers revealed by a close correlation between force and protein localization
J. Cell Sci., 122 (10), (2009), 1665-1679
DOI: 10.1242/jcs.042986

H. Kress, E. H. K. Stelzer, D. Holzer, F. Buss, G. Griffiths, A. Rohrbach
Filopodia act as phagocytic tentacles and pull with discrete steps and a load-dependent velocity
PNAS, 104 (28), (2007), 11633-11638
Supplementary Movies: Movie1.mov, Movie2.mov
• Named by Discover magazine as one of the 'Top 100 Science Stories of 2007'
DOI: 10.1073/pnas.0702449104

E. Anes, P. Peyron, L. Staali, L. Jordao, M.G. Gutierrez, H. Kress, M. Hagedorn, I. Maridonneau-Parini, M.A. Skinner, A.G. Wildeman, S.A. Kalamidas, M. Kuehnel, G. Griffiths
Dynamic life and death interactions between Mycobacterium smegmatis and J774 macrophages
Cellular Microbiology, 8 (6), (2006), 939-960
DOI: 10.1111/j.1462-5822.2005.00675.x

Selected publications on optical theory and simulation

H. Kress, E. H.K. Stelzer, A. Rohrbach
Tilt angle dependent three-dimensional position detection of a trapped cylindrical particle in a focused laser beam
Appl. Phys. Lett., 84 (21), (2004), 4271-4273
DOI: 10.1063/1.1737056

A. Rohrbach, H. Kress, and E. H. K. Stelzer
Reply to comment on "Trapping forces, force constants and potential depths for dielectric spheres in the presence of spherical aberrations"
Appl. Opt., 43 (9), (2004), 1827-1829
DOI: 10.1364/AO.43.001827

J. E.N. Jonkman, J. Swoger, H. Kress, A. Rohrbach, E. H.K. Stelzer
Resolution in optical microscopy
in: Methods in Enzymology, Biophotonics Part A, 360, (2003), 416-446
DOI: 10.1016/S0076-6879(03)60122-9

A. Rohrbach, H. Kress, E. H. K. Stelzer
Three-dimensional tracking of small spheres in focused laser beams: influence of the detection angular aperture
Opt. Lett., 28 (6), (2003), 411-413
DOI: 10.1364/OL.28.000411

Publications on optical trapping and tracking in­stru­men­ta­tion

H. Kress, E. H.K. Stelzer, G. Griffiths, and A. Rohrbach
Control of relative radiation pressure in optical traps: Application to phagocytic membrane binding studies
Phys. Rev. E, 71 (6), (2005), 061927
DOI: 10.1103/PhysRevE.71.061927

H. Kress, E. H. K. Stelzer, A. Rohrbach
Measuring and adjusting the trapping position in optical tweezers
in: DGaO Proceedings, (2005), ISSN: 1614-8436
pdf

A. Rohrbach, H. Kress, E. H. K. Stelzer
Three-dimensional tracking of small spheres in focused laser beams: influence of the detection angular aperture
Opt. Lett., 28 (6), (2003), 411-413
DOI: 10.1364/OL.28.000411