One Chip To Sample Extraterrestrial Chemicals

A new lab-on-a-chip device can analyze a fluid sample for the presence of amino acids, making the device the first to complete such a task in a single microdevice without intervention or auxiliary components (Anal. Chem., DOI: 10.1021/ac202095k).

To sample biologically relevant molecules in extraterrestrial environments such as Mars or Titan, devices need to withstand the rigors of space, says chemist Peter A. Willis, at NASA’s Jet Propulsion Laboratory at California Institute of Technology. Mechanical and electronic simplicity is a must.

It’s difficult to compress so many discrete functions onto one chip: Tasks such as concentration, separation, and detection require different conditions, such as pH. Until recently, most lab-on-a-chip devices, which rely on capillary electrophoresis, have incorporated some but not all of the tasks involved in analyzing organic molecules. For example, researchers have made devices capable of separations and simple fluidic routing, but had not until now integrated them with the components that analyze the sample.

To make their multitasking chip, Willis explains, he and his colleagues designed an array of pneumatic valves and pumps that ferry the sample into wells, where, for example, fluorescent labels are attached to amino acids. Microcapillary electrophoresis separates the amino acids in the sample, and then laser-induced fluorescence detects them. This device is a major step forward, Willis says, because it does microfluidic manipulation autonomously so that it can conduct tasks such as sample labeling and serial dilutions. Those tasks previously required human operators.

Carlos D. Garcia, associate chemistry professor at the University of Texas, San Antonio, who develops microfluidic chips, says he’s impressed with the chip’s capabilities. “I think it’s beautiful,” he says. “I’m so jealous of this chip!”

Jed Harrison, chair of the chemistry department at the University of Alberta, also praises the work, calling it “an exciting and substantive step forward in fully automated microfluidic systems, one that is certainly going to be required for deploying microfluidic systems in extraterrestrial analysis.”

Though the researchers designed the device for extraterrestrial missions, it could also find use on Earth, Willis says. He hopes to see the device eventually expanded into a reprogrammable chemical analyzer.