Non-contact optical tweezers-based single cell analysis through in vivo X-ray elemental imaging

We report on a radically new elemental imaging approach for the analysis of biological model organisms and single cells in their natural, in vivo state. The methodology combines optical tweezers (OT) technology for non-contact, laser-based sample manipulation with synchrotron radiation confocal X-ray fluorescence (XRF) microimaging for the first time. The main objective of this work is to establish a new method for in situ elemental imaging of free-standing living biological microorganisms or single cells in their aqueous environment. Using the model organism Scrippsiella trochoidea, several successful test experiments focussing on applications in environmental toxicology have been performed at ESRF-ID13, demonstrating the feasibility, repeatability and high throughput potential of the OT XRF methodology. We expect that the OT XRF methodology will significantly contribute to the new trend of investigating microorganisms at the cellular level with added in vivo capability.