We present and discuss a new experimental setup to perform small angle X-ray scattering and diffraction (SAXSD) of localized liposome colloidal microparticles. A home-built inverted infrared laser tweezers microscope is used to trap, manipulate and aggregate micron-scale liposome particles at single locations inside a 100 microns glass capillary. The micro-focused X-ray and the laser beams are aligned to intersect each other perpendiculary, allowing to associate the X-ray diffraction signal to the micron-sized region of interest inside the capillary. Throughout the laser tweezer setup, using diffractive optical elements implemented on a spatial light modulator, we are able to manipulate small aggregates of colloidal particles (liposomes) and fix them in the optical path of the X-ray beam. We present and discuss first scattering and diffraction experiments on phospholipid liposomes, at the ID13 microfocus beamline of the European Synchrotron Radiation Facility (ESRF). The results demonstrate that we can push the limit of measurable cluster size close to a single liposome.

Date Published: 11 September 2006
PDF: 6 pages
Proc. SPIE 6326, Optical Trapping and Optical Micromanipulation III, 63261M (11 September 2006); doi: 10.1117/12.680643

Published in SPIE Proceedings Vol. 6326:
Optical Trapping and Optical Micromanipulation III
Kishan Dholakia; Gabriel C. Spalding, Editor(s)