Laptop Lab

Carrying around a full-sized mass spectrometer could well hinder the quest for alien life – even in lower gravity. And so, with the aim of downscaling off-planet chemical analyses, NASA has developed a portable lab that could be taken onboard a spacecraft or mounted on a Mars rover. We spoke with Peter Willis (picture, below), co-developer and NASA scientist, to find out more about the chemical laptop.

What inspired the “chemical laptop”?

Essentially, I was motivated by the search for life on other worlds. The regular approach used on NASA missions usually involves taking solids and performing gas phase mass spectrometry to look for biological molecules. My approach is to use liquids for all stages of the analysis rather than gases, because it is drastically more efficient at extraction and also analysis. I wanted to develop a small portable instrument that could be used on spacecraft, and that would be reprogrammable by NASA mission operations personnel. And I realized that by solving this problem for NASA applications, we would also provide something that would be generally useful to society. I named it “the chemical laptop” so that people would be able to quickly understand that it was a portable instrument that looks like a laptop, that can be “reprogrammed” to perform different chemistry experiments.

How does it work?

The base unit contains all the electronics, optics, and software just like a regular laptop.  But there are two other important replaceable components. One is a microfluidic chip where the liquid analysis takes place. The other is a replaceable reagent cartridge that holds wet and dry chemicals needed for analysis. The user adds an unknown sample to the input port on the chip and selects an “application” from the laptop that is designed to look for a certain class of molecule. Then the unit performs all the steps needed for a chemical analysis: mixing, pumping, labeling, separation, and detection. Mixing, pumping and labeling is done using microfluidic valves on the surface of the chip that are opened and closed using gas pressure. Separation is performed using electric fields, and detection is achieved by measuring the fluorescence produced by labeled target molecules after they are hit by a laser beam.  Measuring the fluorescence of molecules as they travel through a microchannel allows us to determine the identities and quantities of the molecules present. In our search for life, we are typically looking for quantities of biological molecules, such as amino acids or fatty acids in a sample, and their geometric distributions.

What was the biggest hurdle during development?

We’ve been tackling two big hurdles – and they are intimately related to one another. The first is the design and development of a fully integrated system for the pneumatics, electronics, and optics. We are basically squeezing all the components of a chemistry laboratory into an entirely new packaging format, where only solid blocks of material are used as the starting materials (just like in computer chip development). So there are no “tubes” inside the chemical laptop, but it still has to distribute both gases and liquids throughout complex networks. The second hurdle is in complete automation. The sample has to be introduced and data has to come out, without any tweaking by the user. This is a tremendously difficult and underappreciated problem. I think it is fair to say that these problems are universal in the field of microfludics, which has been slow to deliver useful technology.

Where do you see this kind technology heading?

I see a future where this type of technology is integrated into smart phones and tablets.  The phones won’t actually look any different but there will be an additional input like a headphone jack where samples can be introduced, and a slot the size of an SD card for reagents to be added. You will download an app with the software for an analysis and, if necessary, you would receive a tiny vacuum-sealed reagent cartridge in the mail. I see progress being driven by open source development rather than one big company. And I believe that for this to really take off and benefit society, we would need to decide upon a single set of standards that everyone can use and go from there. That would leave people to focus on developing the applications.

What next?

We need to get this technology ready for a field test in the Atacama Desert in Chile (a location that is similar to Mars) by January 2017. As part of a collaboration with Brian Glass at NASA Ames, we will be mounting our instrument on a test rover that will drill and deliver powdered samples to the instrument. We needed to develop a new front end for the instrument that takes powdered dirt and extracts molecules from the dirt using heated liquids.  Basically, it’s like a mini espresso maker for dirt. And we need to automate this entire process so that it can be performed by the operators of the test rover. In addition, we are developing new methods that could be used to analyze material collected from moons like Europa and Enceladus. In those cases, the sample would be ice collected in a vacuum. Here, we need to develop a system that could work inside a vacuum chamber that simulates these conditions.

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