At A Glance:
• Paul Todd, Chief Scientist, SHOT
• BA — Bowdoin College (1959)
• SB — Massachusetts Institute of Technology (1959)
• MS — University of Rochester (1960)
• PhD — University of California, Berkeley (1964)
• 1991-2000 — Research professor, chemical engineering, University of Colorado, Boulder.
• 1988-1991 — Physicist, National Institute of Standards and Technology.
End-to-end microarray analysis in zero gravity? Right now, it’s not practical. In space terms, the technology is in the pre-Sputnik era. However, with the growth and adaptation of this technology, microarrays are poised to leave the lab and enable massively parallel assays in even the most extreme conditions — like those of space.
Paul Todd, chief scientist for Space Hardware Optimization Technology (SHOT) of Greenville, Ind., and a veteran of commercial low gravity projects, is in the forefront of hauling life science technologies to the upper edges of the atmosphere.
SHOT, has long been a partner with NASA, today producing devices like the Adsep, a microwave-oven-sized piece of hardware with temperature controls, an internal computer, and the ability to robotically conduct three concurrent life sciences experiments in a miniature space laboratory environment that can easily fit into the tight quarters of the space shuttle. The 15-year-old, 30-employee company, has successfully provided the technology for protein crystal manufacturing on the shuttle and now has a $175,000 NIH grant, “Biomolecule Crystallization Microarray,” to produce a system to create crystals of biomolecules for crystallography with pharmaceutical applications.
On the day after the most recent shuttle launch, BioArray News spoke with Todd about microarrays in the extreme.
What kind of interest is there among researchers for doing microarray analysis in space?
Microarrays are definitely on the minds of space life sciences researchers. The NASA Ames Research Center is collecting technology in this area as a means of attempting to complete the [microarray analysis] operation in orbit. When an experiment is aboard the space station, typically, you don’t have access for three months at a time. That means you would rather not have your stuff sitting around in RNAlater or finding some way to freeze it at minus-80 degrees Celsius. It would be better to complete the processing and analysis right on orbit. For that reason, NASA and companies like us are looking for ways to go from living cells and tissue, all the way to gene expression analysis. You can’t do that now, it will take lab-on-a-chip approaches, microfluidics, as well as some means of accessing and analyzing the gene arrays once the extraction and reaction processes have been completed.
What can researchers expect to come out of your work?
There have been some experiments done on gene expression by cells in space. The results found by researchers so far have been spectacular beyond expectation. Now, we have to try to figure out why. Out of something on the order of 10,000 to 20,000 genes expressed, some 2,000 of them are up-regulated or down-regulated, and that’s in cellular model systems. There are some possible explanations. One of them has to do with the way that masses move in the absence of gravity. There are two ways that molecules get together in wet chemical systems — they diffuse or convect. You can do the former, but not the latter in space. We presume that, if you wait long enough, diffusion will bring the molecules together and they will hybridize. I wouldn’t think of that as one of the major hurdles. The major hurdles consist in the total automation. All of this processing will have to occur untouched by human hands. The microarray readers today are fairly big. We know here at SHOT that does not have to be the case. You should be able to read a microarray using a device about the size of your notebook. I suspect those are going to hit the market in the next three years.
Your company has earned an NIH STTR grant for protein crystallization hardware. Can you tell me about it?
This is an array of micro-reactors on a chip, and it’s used for growing crystals. It’s a fairly advanced project; it won’t see space for a good many moons. Three-dimensional structure is the goal of the crystallography game. You need good crystals for x-ray diffraction, and you need x-ray diffraction to determine the atomic coordinates of molecules; you need the atomic coordinates of molecules for rational drug design using molecular graphics. Our proposed protein crystal growth micro-array is a lab on a chip, taking the place of one experimenter and probably several cubic feet of instruments.
What is SHOT’s space history?
We were on the flight on which John Glenn was a crew member. [He had the job of changing the cassettes on the lab hardware.] That flight was designed to test the concept that we could do protein crystallization with our hardware, and also ask some scientific questions about the physics of protein crystal growth. That was a very successful set of experiments with 43 out of 44 experiments yielding useful results.
When is your next space flight?
On the STS-115 mission, which is currently scheduled for May 23. We will be growing crystals on that flight, among other things. We have three customers who will be doing gene expression studies. We are providing them with culturing equipment and, in one case, rodent cells; in another bacterial cells, and another case, invertebrate cells. At least two of them will be using micro-arrays. The third will most likely study RNA expression patterns by electrophoresis.
What technical hurdles have you overcome?
One is retrieving the RNA from space, and the methods of fixation and extraction that are normally required. We are providing mainly the opportunity to preserve the samples in RNAlater, a solution that supposedly inactivates ribonuclease so that the RNA molecules that are synthesized during gene expression are preserved. RNA later is a very strong solution, and more or less proprietary. The effect is for the RNA not to degrade and to be ready to be extracted using characteristic Trizol solutions to capture the RNAlater. It seems to be a pretty good preservative of whole messenger sequences.
The alternative is to extract directly into Trizol solution, which is a pretty nasty phenol solution of guanidinium isothiocyanate and 20 percent so-called inert ingredients. This reagent is not so easy to manage in space. Everything that goes inside our hardware has to be approved by NASA toxicological and safety officials. Right now, for example, they are reviewing a very lengthy list of chemicals that will be used in our experiments in May to let us know what we can and cannot use. When we use them, we have to put stickers on the outsides of the containers indicating a NASA-specified level of toxic hazard. Our company specializes in doing the government paperwork that makes it possible for our customers to fly their experiments. If you brought this paperwork to a crystallographer and said this is what you need to do to grow a crystal in space, they would quickly lose interest. In our experience the paperwork weighs more than the payload, by a great margin. On our last mission, the paperwork weighed more than 400 pounds, compared to 70 pounds for the payload.
How does your product work?
Our space processing facility is a very complicated box run by an internal mother computer. The amount of time it took, from invention to flight, in our hands, is something on the order of a three-year cycle. In most other hands, it’s longer. You have to be inventive. There is a complete and totally automated lab in each of those cassettes. Obviously, the things that go on inside have to be operated remotely, electronically. The mother comp-uter communicates to the cassette through a 37-pin connector to all its internal components, each of which is something you would find in a biochemistry lab, but it doesn’t look like what you see in a typical lab. It’s totally enclosed: That’s one of the hurdles. You just can’t pour liquids from A to B. Everything has to be totally contained, and then, of course, transferred and mixed on schedule. The computer performs to a schedule; it opens valves and operates pumps, for example. All of the chemistry takes place on an automated basis. The whole facility can’t weigh more than 70 pounds, but it has to contain the equivalent of a lab investigator, an incubator, a lab bench with analytic instrumentation on it, and a pipetter — with all of these things condensed into a closed-fluid circuit in a fraction of a cubic foot of space. And, you can’t consume more than 150 watts of electric power. Depending on where it gets mounted in the space craft, you can also interact with it from the Earth. Our facility will fly in the mid-deck of the space shuttle in May, so we won’t have that telemetry capability. But, we won’t need it; we will use the device’s internal software to execute the entire 10-day operation.
Back on earth, how will you commercialize this?
We have one lab instrument for cell separation in beta testing. We expect to have one or two more by the end of this calendar year. We are hoping to start some sales this year as well. We have a number of agreements in place and we have a certain amount of SBIR and state support to put us into the terrestrial marketplace. We call this “SHOT Scientific” to market Earth-based benchtop products. We received $1.9 million from the State of Indiana to develop technologies to make them useful and user-friendly to scientists on the ground.