A simple apparatus for time-resolved x-ray diffraction biostructure studies using static and oscillating pressures and pressure jumps

Abstract

A beryllium rod with an internal bore diameter of 1.5 mm and a wall thickness of 2.4 mm constitutes an x-ray compatible cell for hydrostatic pressures rated up to 1800 bar (180 MPa, 26 000 psi) at temperatures up to 90 °C. The system can be used to produce static and oscillating pressures, pressure ramps, and pressure jumps. Pressure is generated by compressing water, the pressure medium, in a syringe-type high-pressure pump. Commercially available pressure valves serve to produce sinusoidal pressure oscillations and pressure jumps for any initial and final pressure between atmospheric pressure and 1800 bar. Typical rise times for a minimally damped and damped pressure jump from atmospheric pressure to 1600 bar are ∼2 and 5 ms, respectively. A depressurization jump from 450 bar to atmospheric has a decay time of order 5 ms. This equipment has the advantage of being relatively easy to build and to operate. However, it does not provide the fastest possible pressure jumps. The assembly of thermocouples and wire feedthroughs for operation under high pressure is detailed. The apparatus described here has been used in time-resolved x-ray diffraction studies of lipid phase transitions using synchrotron radiation. We anticipate using it to collect static and slow kinetic data on a conventional x-ray source.

Pressure effects on lipid membrane structure and dynamics

“…Versions of this type of pressure cell have been developed by several groups since 1982 (Leszczynski et al, 1993;Mencke et al, 1993;Pressl et al, 1997;Suski et al, 1982). However, a significant landmark was reached with the development of a robust and versatile cell system by Woenckhaus et al (2000).…”

“…There have been a number of sample cells and pressure systems produced to carry out high pressure experiments up to 1 GPa (Ando et al, 2008;Brooks et al, 2010;Duesing et al, 1996;Kato and Fujisawa, 1998;Krywka et al, 2008;Mencke et al, 1993;Pressl et al, 1997;Woenckhaus et al, 2000) which have been designed to address the need for fine pressure control of soft condensed matter systems and these cells are ideally suited to studying pressure effects on lipids. These systems have all used the pressure pump and high pressure network concept, described above, to generate and control high pressure.…”

“…Here we focus on the primary techniques that have been used in the study of lipids: X-ray diffraction (Ando et al, 2008;Brooks et al, 2010;Duesing et al, 1996;Kato and Fujisawa, 1998;Krywka et al, 2008;Mencke et al, 1993;Pressl et al, 1997;Woenckhaus et al, 2000), nuclear magnetic resonance (Bonev and Morrow, 1997b;Peng and Jonas, 1992), optical microscopy (Nicolini et al, 2006a;Reck et al, 1998;Salmon and Ellis, 1975;Vass et al, 2010) and infrared spectroscopy (Czeslik et al, 1998;Kato and Taniguchii, 1995;Schiewek et al, 2007).…”

High pressure neutron and X-ray diffraction at low temperatures

“…This cell is useful where extremely fine pressure control is required over a small range [103]. One particular example where a similar design is used, concerns the time-resolved study of pressure effects in bio-structures, using a pressure controller to step and jump the pressure in a controllable manner [104].…”

Pressure induced hydration dynamics of membranes

“…The instrumental resolution (FWHM) for the scattering angle was ∆θ ∼ 1 × 10 −3 rad. Fast pressure jumps with a rise-time ∼ 7 ms were obtained by the opening of a high-pressure valve driven by a computer-actuated pneumatic piston, similar to the method of Caffrey and co-workers [13]. The pressure jumps resulted in small temperature changes (∼ 2 K for a 0.5 kbar jump) as measured by a fast response thermocouple embedded within the sample.…”