Labcyte release acoustic sample preparation technique

The new release, which received an honorable mention in the Pittcon Editor's Awards, allows precise spatial matrix deposition and automated multi-step sample preparation protocols for MALDI (matrix-assisted laser desorption ionization) mass spectrometry imaging.

The precise spot-on-spot placement prevents biomolecules from migrating through large wetted areas and the ability to control the drying time between depositions allows the optimization of solvent penetration, reaction chemistry, crystal formation and spot size to yield higher quality and more reproducible mass spectra and images.

MALDI imaging can be used to find new biomarkers and for studying drug / tissue interactions (pharmacokinetics) in drug discovery as well as for studying biopsies in pathology labs.

The up-take of the imaging technique has been hampered by the need for expert knowledge to prepare the samples.

The two most common techniques for sample preparation are pneumatic spray and nano-spotting.

Bruker recently introduced their ImagePrep platform to overcome some of the hurdles.

The Portrait 630 uses sound energy to transfer ultra-low volumes of matrix to the sample - a technique known as acoustic droplet ejection (ADE).

ADE works by transmitting sound waves through the bottom of a fluid reservoir and through the liquid matrix causing a droplet to be ejected from the liquid.

Droplets as small as one picolitre (10 -12 litre) and as large as 10 microliters can be ejected using the technique.

Nothing ever touches the sample, eliminating the risk of cross contamination and as the droplets are discrete no migration of chemicals can occur across the surface.

As there are no nozzles or tips, there is no chance of clogging, even when using crystallizing agents or proteins.

The instrument allows the automation of multi-step protocols, precise drop-on-drop positioning and flexible droplet timing to facilitate sequential experiments such as proteolytic digests followed by matrix deposition.

The inclusion of a CCD imaging system allows the user to choose specific spots of interest on a sample, such as stained tumour cells in pathology samples.

The largest sample plate holder measures 123mm by 81mm, large enough to hold complete mouse cross-section tissue samples.

The CCD also allows the user the see the deposited matrix on the sample and check the positioning of the spots.

ADE introduces only very small amounts of energy that are not enough to dissolve a solid or to break up a mass of particles.

ADE can be used to transfer live cells, which do not suffer any adverse effects from the sonic energy.

The technology is also useful for high throughput screening, the manufacture of protein or oligonucleotide arrays, the manufacture of mono-dispersed particles and coating medical devices with active compounds.