Optical Tweezers for Synchrotron Radiation Probing of Trapped Biological and Soft Matter Objects in Aqueous Environments

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• 作者：Silvia C. Santucci ; Dan Cojoc ; Heinz Amenitsch ; Benedetta Marmiroli ; Barbara Sartori ; Manfred Burghammer ; Sebastian Schoeder ; Emanuela DiCola ; Michael Reynolds ; Christian Riekel
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：June 15, 2011
• 年：2011
• 卷：83
• 期：12
• 页码：4863-4870
• 全文大小：1027K
• 年卷期：v.83,no.12(June 15, 2011)
• ISSN：1520-6882

文摘

Investigations of single fragile objects manipulated by optical forces with high brilliance X-ray beams may initiate the development of new research fields such as protein crystallography in an aqueous environment. We have developed a dedicated optical tweezers setup with a compact, portable, and versatile geometry for the customary manipulation of objects for synchrotron radiation applications. Objects of a few micrometers up to a few tens of micrometers size can be trapped for extended periods of time. The selection and positioning of single objects out of a batch of many can be performed semi-automatically by software routines. The performance of the setup has been tested by wide-angle and small-angle X-ray scattering experiments on single optically trapped starch granules, using a synchrotron radiation microbeam. We demonstrate here for the first time the feasibility of microdiffraction on optically trapped protein crystals. Starch granules and insulin crystals were repeatedly raster-scanned at about 50 ms exposure/raster-point up to the complete loss of the structural order. Radiation damage in starch granules results in the appearance of low-angle scattering due to the breakdown of the polysaccharide matrix. For insulin crystals, order along the densely packed [110] direction is preferentially maintained until complete loss of long-range order.