Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

Abstract

We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 μm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30° can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

Optothermally actuated capillary burst valve

“…4 In a capillary burst valve, the air-liquid meniscus is pinned by an abrupt change of geometry in a microfluidic channel. In its simplest form, the capillary burst valve is applied for windowless microfluidics 5 or filling complex microfluidic networks; 6,7 however it is in capillary microfluidics 8 and centrifugal microfluidics 9 that capillary burst valves play a central role. A valve can be predictably burst by increasing the centrifugal force above a threshold that depends mainly on its position on the rotating disc as well as on the length of the liquid column and the density of the liquid.…”

Singular value decomposition as a tool for background corrections in time-resolved XFEL scattering data

“…The samples can be ensembles of single particles [4,5], suspensions of nanocrystals [6] or solutions of the compound of interest [2]. Sample delivery systems are undergoing much development and can be tailored to the sample properties [7,8].…”