Since 2009 I have been working in the Non-Periodic Imaging group, at the Stanford PULSE Institute at SLAC, where I have been exploring technologies to deliver biological samples into X-ray free electron lasers. Our microfluidic electrokinetic sample holder (MESH) injector is based on electrospinning techniques. The high viscosity of the carrier fluid reduces the sample consumption on the order of hundreds of nanoliters per minute, thus minimizing the sample consumption of the protein of interest. The applied electric field focuses the fluid from the exiting capillary (typically between 50 to 100 micrometers in diameter) down to a narrow jet (on the order of one micrometer).
I have also used complimentary techniques to deliver other samples in which single particle imaging is desired, or high viscosities is not compatible with the sample of interest. These techniques include aerosolized injectors, like electrospray sources and aerodynamic lens stacks, and other liquid injectors, like gas dynamic virtual nozzles and piezoelectric droplet dispensors.
I am also exploring new means of characterizing samples, such as single particles or protein crystals, in order to ensure the proper concentration and size distribution for delivery to the X-ray source. One such method is the Nanosight particle tracking system.
