Ceramic micro-injection molded nozzles for serial femtosecond crystallography sample delivery

Abstract

Serial femtosecond crystallography (SFX) using X-ray Free-Electron Lasers (XFELs) allows for room temperature protein structure determination without evidence of conventional radiation damage. In this method, a liquid suspension of protein microcrystals can be delivered to the X-ray beam in vacuum as a micro-jet, which replenishes the crystals at a rate that exceeds the current XFEL pulse repetition rate. Gas dynamic virtual nozzles produce the required micrometer-sized streams by the focusing action of a coaxial sheath gas and have been shown to be effective for SFX experiments. Here, we describe the design and characterization of such nozzles assembled from ceramic micro-injection molded outer gas-focusing capillaries. Trends of the emitted jet diameter and jet length as a function of supplied liquid and gas flow rates are measured by a fast imaging system. The observed trends are explained by derived relationships considering choked gas flow and liquid flow conservation. Finally, the performance of these nozzles in a SFX experiment is presented, including an analysis of the observed background.

Double-flow focused liquid injector for efficient serial femtosecond crystallography

“…Into this, a 40 μm inner diameter (ID)/105 μm outer diameter (OD) round fused silica capillary (Polymicro, USA) was inserted after slightly etching the inner wall of the outer capillary with hydrofluoric acid to accommodate the 105 μm diameter. All fused silica capillaries were sharpened by wet mechanical polishing21 before assembly. Two Kapton rings (so called ‘spacers’) were placed around the outer liquid line (as reported before ref.…”

Mixing injector enables time-resolved crystallography with high hit rate at X-ray free electron lasers

“…Typical devices produced a stable jet for total flow rates above 10 to 20  μ l/min, performance comparable to non-mixing GDVNs (∼10  μ l/min) 29 . In a mixing experiment, devices are designed so that the total flow rates will exceed this number (see discussion), so jet instability is not a concern.…”

Jet delivery system for Raman scattering on bio-inorganic compounds

“…Hence, the endoscope camera facilitated the adjustment of the jet focus point. We used ceramic-based gas dynamic virtual nozzles 17 for generation of the micro jet. [18][19][20][21][22][23][24][25][26][27][28] To fit the nozzle to the jet chamber, we designed a special short nozzle with a 10-mm long ceramic piece.…”

“…The spot size of the UT-3 Raman setup was adjusted to 20 lm. In order to increase the original micro-jet diameter of 2-5 lm, 17 we systematically changed certain jetting parameters. The micro jet diameter D j is given by [17][18][19][20][21][22][23][24][25][26] …”