“If you yell loudly enough at a liquid, some of it will move.”
It’s true, Rich Ellson, the chief technology officer for Labcyte told Inside Bioassays last week. It turns out it’s true for cells, too, as well as a variety of other substances that might be used in a high-throughput biology experiment.
Of course, Labcyte’s technology is a bit more refined than the stated method. But the concept, known as rapid acoustic transfer, is the basis for a wide patent portfolio that the Sunnyvale, Calif.-based company has collected related to its Echo 550 Compound Reformatter, which the company introduced just over a month ago.
Currently, Labcyte has been issued 13 US patents — including four in the past month — regarding the use of the Echo 550 for everything from sample dispensing for high-throughput assays to microarray preparation.
Last week, the company announced the issuance of one of its most recent US patents, number 6,802,593, entitled “Acoustic ejection of fluids from a plurality of reservoirs,” which covers methods for rapidly transferring fluids, such as assay media, from multi-well plates using focused acoustic energy.
Also last week, the company was awarded US Patent number 6,809,315, “Method and system using acoustic ejection for preparing and analyzing a cellular sample surface. This patent protects a technique for acoustically transferring droplets of an analysis-enhancing fluid, such as MALDI matrix gel, onto cellular or tissue surfaces for subsequent analysis.
According to Ellson, the Echo 550 has multiple uses in cell-based assays and high-content screening, although not all of them have been completely worked out yet.
“There are really two aspects of cell-based assays in terms of assembling them,” Ellson said. “One of them is what is qualified on the machine right now, which is the ability to transfer the drug compound into a well. And then [the second step is] to add cells and the nutrients that they need, and whatever other components are necessary for assay detection.”
The Echo 550 is set up to perform compound transfer on 1,536-well microplates, which, according to Ellson, typically have volumes on the order of 10 microliters, but are usually filled with only about 5 microliters of material.
One of those materials is often DMSO, the solvent in which small-molecule compounds are kept. Although DMSO is essential for compound library storage, too much of it can negatively effect cell permeability and even cell health.
“People don’t generally like to put in DMSO concentrations that end up being higher than one part in 100, or one part in 1,000,” Ellson explained. “So if you had 5 microliters, or 5 millionths of a liter, you’d need to actually get to 5 billionths of a liter, or 5 nanoliters, in order to get the DMSO compound solution into a 1,536-well plate at a low-enough volume so as not to influence the assay.
“That was one of our design goals with the Echo 550 — to enable it to actually hit 5 nanoliters in volume for a 1,536-well plate — and that’s the capability that’s [presently] out there in the field for transferring a compound,” he added. Most dispensing technology on the market, Ellson said, shows large variability below the 50 microliter threshold, whereas the Echo 550 shows a great deal of consistency even at its ultra-low dispensing volumes.
The other cell-based application that Labcyte has been testing is actually using acoustic energy to move cells from a central repository into well plates for subsequent assaying.
“In the lab, we’ve done a lot of work in actually transferring the cells,” Ellson said. “It turns out that the process is very gentle — it’s not pushing the cells through a hole or an orifice. It’s more like the whole area of liquid around them [forms] a little droplet, and flies off to the target. That’s pretty cushiony for the cell, to not subject it to any shear or distressing forces, so they transfer across without any problems.”
Ellson said that although Labcyte has demonstrated this application in the laboratory, it still hasn’t been “certified” as a commercial application. This is because the Echo 550 is designed to transfer DMSO, and not a typical cell culture nutrient like DMEM.
“There’s no uncertainty about the physics or the health of the cells,” Ellson said. “We’ve transferred oodles of different cell lines in the lab — typical [mammalian] cells that you would use in a pharma assay: HeLa cells, CHO cells, etcetera. Basically we can never find any assay that shows that the cells we move this way are less healthy than cells that are moved by conventional means,” he said. “If anything, it’s friendlier than some of the processes that are out there.”
In addition, Labcyte said it needs to consider issues such as keeping the cells healthy in a central area prior to dispensing, which Ellson said would involve “making the machine much more of an incubator than it is now.”
Eventually, the company envisions one instrument that will be able to perform multiple applications through an entire assay process — from dispensing cells into wells, to adding compounds, nutrients, and other assay reagents.
“There’s nothing different about the mechanics,” Ellson explained. “It’s just teaching it to work with the different materials. It’s just like if you went in for a medical ultrasound, your liver tissue has different properties than your kidney. They can both be imaged by the same acoustic device. They’re close in properties, but they’re not identical.
“It’s essentially the issue we have with DMEM vs. DMSO,” he added. “We have to make sure the machine understands what it’s working with, so that it can always very accurately dispense the liquid media.”
Making MALDI Easier
Yet another, relatively nascent application for the Echo is that which is covered by the patent issued last week: depositing droplets of a MALDI matrix material onto plates, or directly onto cells or tissue samples.
“Because we don’t actually touch the liquids, but move them with sound, we can work with liquids that most people consider to be very difficult to work with,” Ellson said. “And one of those is MALDI matrix material. The nasty thing from the perspective of someone trying to move around MALDI matrix is that it’s very volatile, it tends to have acids in it like [trifluoroacetic acid], and it’s designed to have the crystal material that you’re going to ionize at very high concentrations.
“You can imagine that if you wanted to move that around with a piezo tip or essentially a nozzle, the stuff essentially crusts over almost immediately,” he added. “So it’s really difficult to work with and distribute reliably because you’ll almost always get a clogged nozzle or junk collecting around the orifice.”
Labcyte thinks the Echo can help solve this because the machine acoustically transfers tiny droplets of the material directly from a relatively large pool, where evaporation of the material is retarded.
Ellson cited the work of Richard Caprioli, a professor of biochemistry and director of the Mass Spectrometry Research Center at Vanderbilt University. Caprioli, who is one of the co-inventors listed on the specific patent, has been conducting experiments to look at protein expression in whole rat tissue sections using the Echo along with MALDI mass spectrometry.
“Basically, he’s taking whole-rat sagittal sections, and putting little drops of MALDI reagents across the whole rat,” Ellson said. “Then you feed the rat something you might want to use as a therapeutic, and you can then basically look organ-by-organ, tissue-by-tissue, micron-by-micron, to find out where the drug goes, how it gets metabolized, and whether any organ in the entire rat is behaving unusually because its protein distribution doesn’t match up with that of the control.
“This is going to be huge for ADME/Tox,” Ellson added.
Labcyte has scored a pair of pharmaceutical customers, although it is adamant about keeping their identities under wraps. According to Labcyte, these companies are testing a plurality of applications using the instrument.
“We just launched the machines commercially earlier this month, and shipped our first commercial units,” Ellson said. “People are having a lot of fun understanding what they can do with the machine, but they’re not quite at the state where they’re ready to talk about it.”
At the recent Society for Biomolecular Screening meeting in Orlando, Tim Spicer, a research scientist with Bristol-Myers Squibb, gave a presentation that showed the Echo 550 saves money equivalent to the cost of an instrument — which is currently priced at $225,000 until the end of the year — in less than one year. He also provided data showing the instrument could increase throughput in well-based screening experiments. It was unclear whether BMS is one of the new pharmaceutical customers to which the company referred.
According to Joe Olechno, Labcyte’s vice president of marketing, the company hopes to be able to present data from some of the work being done at the unnamed pharmaceutical customers at January’s Lab Automation conference in San Jose, Calif.
“Trust me, we’re chomping at the bit, and we want to tell people about this,” Olechno said.