X-MIXING · Efficient mixing method at the microscale for Time-Resolved Serial Femtosecond Crystallography

Efficient mixing method at the microscale for Time-Resolved Serial Femtosecond Crystallography

Liquid mixing is an intriguing physical phenomenon across the scales, attracting the scientific community's attention not only for its open questions but also for its crucial role in technological applications. One of them is Time-Resolved Serial Femtosecond Crystallography (TR-SFX), a revolutionary multidisciplinary method to record molecular movies with an atomic resolution of biochemical reactions by utilizing x-ray free-electron lasers (XFEL) and the diffraction-before-destruction concept. The way of triggering these biochemical reactions is critical to control the process. An instant triggering would be ideal for initiating and mapping their spatio-temporal evolution. Unfortunately, many of them are not light sensitive and need hydrodynamic mixing to start the process correctly. On the one hand, the length scales should be at the micro or even submicron-scale to avoid the backscattering of the liquid that is not ideal for obtaining cleaner diffraction patterns. On the other hand, the temporal scales should be as fast as possible and controllable. State-of-the-art methods utilized in this field take advantage of diffusion mechanisms to produce mixing. In this project, we propose a microfluidic mixing method to overcome the spatio-temporal limitations of diffusion and potentially obtain even 1000 faster mixing rates than current methods can produce. Besides, the versatility of our microfluidic arrangement can address the triggering of reactions by PH or temperature jumps. In this project, we have elucidated the physical mechanisms the interplay between temperature gradients, electrical stresses and mixing in singularity fluid processes and pinch-off dynamics. Precise control of microfluidic mixing and their features is crucial to increase the temporal resolution of time-resolved biomolecular studies with XFEL, which potentially will offer new capabilities for the pharma industry in the design and customization of efficient drugs to cure dangerous diseases. With potential regional and national funding, the ideas conceived in this project will be extended to develop a commercial microfluidic device to address the above crucial challenges in a proper way for the society. These are the overall objectives of the action: . To analyse experimentally the influence of the input parameters on the mixing time. . To analyse numerically the role of both the electro-migration of charges and thermal effects. . To determine the scaling laws for the mixing time as a function of the governing parameters. . To characterize experimentally how temperature affects the capillary cone-jet physics laws.

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