Optical Trap

Optical Trap

Optical Trap

The arrangement of water molecules around hydrophobic surfaces is still somewhat a scientific mystery. Better understanding of these interactions will have high impact on diverse fields, ranging from water treatment to stem cell research, where cells are often adhered to surfaces. Together with scientists at iNANO, we aim to use an optical trap to measure the forces between different types of hydrophobic surfaces (polystyrene, proteins, etc.). Small nano- and micro-particles are trapped using a laser, and experiments on the dynamics after a free fall in a solvent can measure their speed at very high precision. This offers the possibility of measuring the forces that govern hydrophobic interaction.

The optical trap can also function as a microphone, that is able to capture very weak acoustic signals. In this project, we focus on how soundwaves  propagate in water, and specifically, how particles (cells, nanoparticles, membranes, etc.) are affected by other particles in their vicinity by these waves. We’re not saying, that cells are talking to each other, but they might be able to “hear” each other at a certain distance.

Relevant publications:

Villadsen, N. et al. Pushing the limit: investigation of hydrodynamic forces on a trapped particle kicked by a laser pulse. Opt. Express23, 13141 (2015).

Kristensen, M. V. et al. Motion analysis of optically trapped particles and cells using 2D Fourier analysis. Opt. Express20, 1953–62 (2012).

Lindballe, T. B. et al. Three-dimensional imaging and force characterization of multiple trapped particles in low NA counterpropagating optical traps. J. Eur. Opt. Soc. Rapid Publ.6, 11057 (2011).

Lindballe, T. B., Kristensen, M. V. G., Berg-Sørensen, K., Keiding, S. R. & Stapelfeldt, H. Pulsed laser manipulation of an optically trapped bead: Averaging thermal noise and measuring the pulsed force amplitude. Opt. Express21, 1986–1996 (2013).