Screening of protein crystallization trials by second order nonlinear optical imaging of chiral crystals (SONICC)

Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47904, United States.
Methods (Impact Factor: 3.65). 11/2011; 55(4):379-86. DOI: 10.1016/j.ymeth.2011.11.003
Source: PubMed


Second order nonlinear optical imaging of chiral crystals (SONICC) is a promising new method for the sensitive and selective detection of protein crystals. Relevant general principles of second harmonic generation, which underpins SONICC, are reviewed. Instrumentation and methods for SONICC measurements are described and critically assessed in terms of performance trade-offs. Potential origins of false-positives and false-negatives are also discussed.

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    • "When a substantially intense electric field is produced by a laser pulse, molecular dipoles are induced. In the case of a chiral crystal, these induced dipoles are anisotropic on their potential energy surface and allow the sampling of nonlinear, even numbered higher order polarizability terms such as the second-generation harmonic (frequency doubling) (Haupert & Simpson, 2011). Enhanced signal can be measured at half the wavelength of the incident pulse, indicative of chiral crystals due to constructive interference provided by the ordered lattice. "
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