Sabina Santesson

Preliminary tests on the use of an acoustic levitator for liquid X-ray diffraction experiments

Some preliminary tests at the crystallography beamline I711 at the MAX II synchrotron in Lund, Sweden, have shown that it is possible to use acoustical levitation to keep a droplet of liquid and solid (powder) samples in an X-ray beam for a sufficient time for collection of the X-ray diffraction pattern.

Airborne Chemistry for Biological Micro Analysis

A system of novel analytical tools for the analysis of intra- and extra-cellular events on a level of single cells have been developed, comprising equipment for acoustic levitation and piezo-electric flow-through micro-dispensing for nano-volume sample handling and sample preparation. The system has been used to study lipolysis in individual adipocytes using fluorescence imaging detection and shows great promise for future applications such as cell-based secondary high throughput screening (HTS).

Flow-through microdispenser for liquid handling in a levitated-droplet based analyzing system

A flow-through microdispenser actuated by a piezo-electric element is presented. The flow-through design enables droplet ejection from a continuously flowing liquid passing through the device. This also simplifies filling, cleaning and changing liquid in the dispenser since the liquid does not have to pass through the sampling orifice during the process. The total volume of the unit is 400 nL and the droplet volume is normally around 65 pL. The droplets can be ejected with up to 5 kHz frequency. The dispenser is used for sample/reagent handling in a system based on acoustic levitation. The dispenser droplets are supplied to a nodal point of a standing wave in the levitator where a “wall-less” reaction site is created.

Airborn Chemistry Levitated Protein Droplets as a Novel Analytical Tool for Nucleation Screening in Macromolecular Crystallisation

A system of novel analytical tools for fast screening of protein nucleation conditions have been developed, based on acoustic levitation and piezo-electric flow-through micro-dispensing and volume measurement in nano-volumes. The system has been used for study different proteins ability to precipitate by testing different crystallization agents. From this data precipitation diagrams are created and “normal” protein-crystallization procedure can then be performed. Described methodology consumes only minute amounts of the precious protein

Airborne chemistry single cell level

A miniaturized analysis system for the studying of living cells and biochemical reactions in microdrops was developed. Cell studies were performed using single adipocytes in 250‐nL drops. Continuous flow‐through droplet dispensers, developed in‐house, were used for additions to the levitated droplet. Addition of b‐adrenergic agonists stimulates the lipolysis in the adipocytes, leading to free fatty acid release and a consequent pH decrease of the surrounding buffer, a change that can be easily followed using a pH‐dependent fluorophore continuously monitored by fluorescence imaging detection. An analytical method using capillary electrophoresis and nanospray mass spectrometry for measurement of the cAMP level in activated single adipocytes are now being developed for future use in combination with the levitation technique. The levitation approach was also employed for the screening of nucleation conditions for macromolecules. Here, the acoustic levitator offers a simplified way to determine the main featur...