Second-order nonlinear optical imaging of chiral crystals

• Published in: Annual review of analytical chemistry (Palo Alto, Calif.) Vol. 4; p. 419
• Main Authors: Kissick, David J, Wanapun, Debbie, Simpson, Garth J
• Format: Journal Article
• Language: English
• Published: United States 19.07.2011
• Subjects: Amino Acids - chemistry; Crystallization; Stereoisomerism
• ISSN: 1936-1335
• DOI: 10.1146/annurev.anchem.111808.073722

Second-order nonlinear optical imaging of chiral crystals (SONICC) is an emerging technique for crystal imaging and characterization. We provide a brief overview of the origin of second harmonic generation signals in SONICC and discuss recent studies using SONICC for biological applications. Given that they provide near-complete suppression of any background, SONICC images can be used to determine the presence or absence of protein crystals through both manual inspection and automated analysis. Because SONICC creates high-resolution images, nucleation and growth kinetics can also be observed. SONICC can detect metastable, homochiral crystalline forms of amino acids crystallizing from racemic solutions, which confirms Ostwald's rule of stages for crystal growth. SONICC's selectivity, based on order, and sensitivity, based on background suppression, make it a promising technique for numerous fields concerned with chiral crystal formation.