Laser-induced alignment of nanoparticles and macromolecules for single-particle-imaging applications

Laser-induced alignment of particles and molecules was long envisioned to support three-dimensional structure determination using “single-molecule diffraction” with x-ray free-electron lasers [PRL 92, 198102 (2004)]. However, the alignment of isolated macromolecules has not yet been demonstrated, also because quantitative modeling is very expensive. We computationally demonstrated that the alignment of nanorods and proteins is possible with standard laser technology. We performed a comprehensive analysis on the dependence of the degree of alignment on molecular properties and experimental details, e.g., particle temperature and laser-pulse energy. Considering the polarizability anisotropy of about 150,000 proteins, our analysis revealed that most of these proteins can be aligned using realistic experimental parameters.