Laser propulsion and deformation-monitoring of cells in optofluidic photonic crystal fibre

21.06.2013, 00:00

Newsletter 6

We have developed a new way to study the biomechanical properties of single cells. These properties are important since they are directly linked to the state of health of the cells. The approach is based on laser-propulsion in optofluidic hollow-core photonic crystal fibre (HC-PCF), the hollow core acting as both waveguide and microfluidic channel. Light is guided in a well-defined single optical mode, resulting in highly uniform optical trapping and propulsive forces in the liquid-filled core. Individual red blood cells were laser-propelled over record distances of 10s of cm. The cells propagate along the centre of the core without touching the glass interface, thus avoiding adherence effects. The confined HC-PCF geometry enhances both the optical and viscous forces, permitting cell-mechanical studies at much reduced laser powers compared to existing approaches. Strikingly, the red blood cells were observed to stretch and fold during propagation through the core (see figure). These shape changes were monitored by measuring the related cell speed using a non-imaging Doppler velocimetry technique. The results suggest that HC-PCF will be useful as a new tool in the study of single-cell biomechanics.

Contact: sarah.unterkofler(at)mpl.mpg(dot)de
Group: Russell Division
Reference: S. Unterkofler et al., J. Biophoton. DOI: 10.1002/jbio.201200180 (2012).