Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals:

Ximeng Y. Dow, Christopher M. Dettmar, Emma L. DeWalt, Justin A. Newman, Alexander R. Dow, Shatabdi Roy-Chowdhury, Jesse D. Coe, Christopher Kupitz, Petra Fromme, Garth J. Simpson

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3 nanoparticles ranging from 200 to 500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.Second harmonic generation correlation spectroscopy was developed as a tool for the characterization of diffusing protein nanocrystals.

Original languageEnglish (US)
Pages (from-to)849-859
Number of pages11
JournalActa Crystallographica Section D: Structural Biology
Issue number7
StatePublished - 2016


  • XFEL
  • correlation spectroscopy
  • protein nanocrystals
  • second harmonic generation
  • size distribution

ASJC Scopus subject areas

  • Structural Biology


Dive into the research topics of 'Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals:'. Together they form a unique fingerprint.

Cite this