Fact Sheet
Overview | Description | Applications | Operations | Results | Publications | Images
Experiment/Payload OverviewBrief Summary
Lab-on-a-Chip Application Development-Portable Test System (LOCAD-PTS) is a handheld device for rapid detection of biological and chemical substances on board the space station. Astronauts will swab surfaces within the cabin, add swab material to the LOCAD-PTS, and within 15 minutes obtain results on a display screen. The study's purpose is to effectively provide an early warning system to enable crew members to take remedial measures if necessary to protect the health and safety of those on board the station.
Principal InvestigatorMarshall Space Flight Center, Huntsville, AL
Charles River Endosafe, Charleston, SC
Carnegie Institution of Washington, Washington, DC
National Aeronautics and Space Administration (NASA)
Expeditions Assigned|14|15|16|17|18|
Previous ISS MissionsLOCAD-PTS is a new investigation for space research.
Experiment/Payload Description
Research Summary
- LOCAD-PTS is a handheld device for rapid detection of biological and chemical substances onboard the International Space Station (ISS).
- LOCAD-PTS analysis is immediate. Effectively providing an early warning system to enable crew to take remedial measures if necessary to protect themselves on board ISS.
- Current testing focuses on detecting bacteria and fungi. Other sample cartridges can be developed to detect chemical substances of concern to crew safety on ISS (hydrazine, ammonia, etc.) and proteins in urine, saliva and blood for aiding medical diagnoses.
The Lab-on-a-Chip Application Development - Portable Test System (LOCAD-PTS) is a handheld device, enabling crew to perform complex laboratory tests on a thumb-sized cartridge with a press of a button. Every thumb-sized plastic cartridge has 4 channels and each channel contains a dried extract of horseshoe crab blood cells and colorless dye. In the presence of bacteria and fungi, the dried extract reacts strongly to turn the dye a green color. Therefore, the more green dye, the more microorganisms there are in the original sample.
Tests by LOCAD-PTS will become increasingly specific with the advent of new cartridges. Current cartridges target bacteria and fungi. New cartridges, to be launched on subsequent flights, will target bacteria only, then groups of bacteria and eventually individual species or strains that pose a specific risk to crew health. Cartridges can also be adapted to detect chemical substances of concern to crew safety on ISS (e.g. hydrazine, ammonia and certain acids) and proteins in urine, saliva and blood of astronauts to provide added information for medical diagnosis. A phrase that summarizes this mode of operation is "same instrument, just change the cartridge."
Applications
Space Applications
This commercial, off-the-shelf technology will help assess the applicability of this technology in many areas relative to microbial detection, crew health diagnostics, and environmental monitoring. The drastic reduction in time for detection (minutes versus days) will provide a capability on ISS that does not currently exist and may help risk mitigation in the event that some type of microbial build-up is observed. Eventually, it is planned that LOCAD-PTS be used to assess water, air, and food supplies in addition to surfaces. Other cartridges are being developed to perform limited crew health diagnostics, monitor other biological molecules such as protein and peptidoglycan, and specific chemicals of potential hazard to the crew e.g. hydrazine and ammonia.
Earth ApplicationsCurrently, the technology is being used to assess fluids used in pharmaceutical processing. The technology has been used to swab the Mars Exploration Rovers (MER), for planetary protection, and to assess microbial contamination in the NEEMO (NASA Extreme Environment Mission Operations) project. This technology will provide quick medical diagnostics in clinical applications. It will also provide environmental testing capabilities that may serve homeland security.
Operations
Operational Requirements
The LOCAD-PTS will be located and operated in the pressurized volume on ISS. The unit will interface to an ISS laptop for power. A swabbing unit has been designed for sampling surfaces, dissolving the sample with water, and delivering precise volumes of sample to the LOCAD-PTS cartridge for analysis. Crew members will use this device to swab various surfaces on board ISS in two phases. In Phase I, the LOCAD-PTS will be used to establish operational correlation between the output from the LOCAD-PTS Reader and culture growth (as determined with agar-based media slides) for various sites in the crew environment. In Phase II of the investigation, PTS results will be compared to the data obtained from the established culture-dependent protocol used for periodic microbial monitoring on the ISS. Results from the analyses will be digitally recorded and downloaded from ISS to ground. No sample return is necessary.
Operational ProtocolsMicroorganisms at various sites on the ISS (e.g. panels and air vents) will be sampled with the swabbing unit, dissolved with water and then dispensed into the LOCAD-PTS cartridge (previously inserted into the LOCAD-PTS Reader). Once the crew has dispensed the sample into the inserted cartridge, pumps in the Reader will draw the dissolved sample into the cartridge where a reaction will take place that produces a green dye in the presence of most microorganisms. The LOCAD-PTS Reader will then measure the absorbance intensity of this green color, compare it with an in-built calibration curve and then display on the screen a quantitative value of lipopolysaccharide (LPS)/beta-1,3-glucan (collectively also known as endotoxin) ranging from 5 to 0.05 endotoxin units (EU)/ml. The sensitivity limit of 0.05 EU/ml correlates to a few bacterial cells per ml. After test completion, the cartridge is removed from the Reader and discarded. If media slides have been used during procedures (such as in Phase I), they will be incubated for 3 days and then photographed, with the images down-linked to ground.
Results/More Information
LOCAD-PTS was operated for the first time on ISS during Expeditions 14 and 15. This instrument uses interchangeable thumb-sized cartridges for the detection of a variety of biological and chemical target molecules. In this first phase of ISS operations, the crew used Limulus Amebocyte Lysate (LAL) cartridges to detect endotoxin - a molecule found in cell walls of certain types of bacteria and fungi - on various surfaces within Node 1 and the US Lab. Five separate sessions were performed over six weeks, with four separate swabs taken for analysis at each site.
In session 1, control test results showed that the instrument and procedures functioned nominally, with the positive control (a swab of the palm) giving a high reading (2.4 endotoxin Units (EU) per 25cm2) and the negative control (no swab) giving the lowest possible reading ( less than 0.05 EU/25cm2). This session also enabled the LOCAD-PTS team to identify an improvement in the procedures (implemented during subsequent sessions) that would help remove air bubbles during the dispensing step and make it easier for the crew to dispense consistent droplet volumes (Jake Maule, "LOCAD-PTS Update" Email to Victor Cooley, Lead Increment Scientist. 17 Apr. 2007). The consistent readings obtained in session 2 (and remaining sessions) indicated that this procedure change had been successful (Jake Maule, "LOCAD-PTS Session 2 Update" Email to Victor Cooley, Lead Increment Scientist. 30 Apr. 2007).
Sessions 1 and 2 revealed that the smooth and flat Node 1 surfaces were relatively clean, an average of 0.1 EU/25cm2, approximately 25 times cleaner than the positive control. The fabric surface of the Temporary Sleep Station (TeSS) in the US Lab analyzed in session 3 gave consistently elevated readings, but still fairly low compared with a typical office desk. The Audio Terminal Unit (ATU) and Air Supply Diffuser (ASD) - analyzed in sessions 4 and 5 respectively, gave more variable readings, correlating with the increased variability of these sites in terms of surface materials and air flow between the four swab areas.
As the number of cartridge types on ISS increases, LOCAD-PTS is set to have an extended array of applications from monitoring the cabin environment for other biological and chemical contaminants to monitoring blood and saliva of the crew to support medical diagnostics. Two types of new cartridge are scheduled for launch to the ISS on a future Space Shuttle mission. The first type will be a fungi-specific test, the second will be a specific to gram-positive bacteria and further cartridges are under development for future flights. Looking further ahead, it is hoped that this type of rapid and portable technology will be implemented on future human lunar missions to monitor the spread of Earth-derived biological material on the lunar surface following landing. This will be important preparation for the human exploration of Mars, where a major scientific goal will be the search for life and differentiation of that signal from biological material brought there by the crew and their spacecraft.
Related Web Sites
Publications
Results Publications
Related Publications
Images
The LOCAD-PTS Reader, cartridge (below Reader) and swabbing unit (to the right). These three components are all that is required to collect a surface sample, dissolve and analyze it to obtain quantitative levels of LPS and beta-1, 3-glucan (with a sensitivity of a single bacterial cell per milliliter). Image courtesy of NASA, Marshall Space Flight Center.+ View Larger Image
Operation of LOCAD-PTS swabbing unit during simulated surface extravehicular activity (EVA) at Meteor Crater, Arizona, as part of NASA's Desert Research and Technology Study (RATS) in September 2005. It has been proposed that future versions of the LOCAD-PTS be used outside the spacecraft during lunar expeditions in 2018 and beyond to monitor biological contamination of the surface associated with human activities. Understanding how we bio-contaminate planetary surfaces will be essential when we prepare human expeditions to search for life on Mars. + View Larger Image
LOCAD-PTS project scientist Dr. Jake Maule from Carnegie Institution of Washington, DC (left) and principal investigator Dr. Norm Wainwright from Charles River Labs (right) test the LOCAD-PTS in zero-g during parabolic flight of NASA's DC-9 aircraft in April 2006. Every aspect of LOCAD-PTS procedures, especially the fluid handling tests, were thoroughly evaluated in a zero-g environment before flight to ISS. Image courtesy of NASA, Marshall Space Flight Center.+ View Larger Image
LOCAD-PTS project scientist Dr. Jake Maule hikes into the active Crater of Mutnovsky volcano in Kamchatka, Russia, with the LOCAD PTS during a NASA Astrobiology Institute (NAI) expedition in 2004. Many interesting forms of microbial life exist in such extreme environments, but when removed from their ambient conditions many die during transport to the laboratory. LOCAD-PTS eliminates this problem by enabling researchers to analyze samples on-site, immediately after sample collection. LOCAD-PTS will return to Kamchatka in September 2006, when Dr. Maule will lead a joint NAI/Russian expedition to Klyuchevsky volcano, one of the most active volcanoes in the world.+ View Larger Image
Dr. Andrew Steele and LOCAD-PTS project scientist Dr. Jake Maule of the Carnegie Institution of Washington analyze ice samples with LOCAD PTS at the peak of Sverefjell volcano in Spitsbergen, Arctic, during the NASA-funded Arctic Mars Analog Svalbard Expedition (AMASE) in 2004. Both will return to this site in August 2006, this time with new LOCAD-PTS cartridges for the detection of protein as well as lipid molecules.+ View Larger Image
Dr. Lisa Monaco examines a microfluidic chip. This chip can be thought of as the 'next generation' of LOCAD-PTS cartridge. It is miniaturized even further to allow many more tests to be completed simultaneously. This will save crew time and allow more sophisticated types of analyses to be performed, ranging from medical tests to monitoring potentially hazardous chemicals onboard. Image courtesy of NASA, Marshall Space Flight Center.+ View Larger Image
NASA Image - ISS014E18794: Expedition 14 Flight Engineer, Suni Williams, uses the swabbing unit to collect samples that will be placed into the cartridges to be analyzed by the LOCAD Reader.+ View Larger Image
NASA Image - ISS014E18822: Astronaut Suni Williams, Expedition 14 flight engineer, works with the Lab-on-a-Chip Application Development-Portable Test System (LOCAD-PTS). Williams is placing the sample mixed with water from the swabbing unit into the LOCAD-PTS cartridge.+ View Larger Image
NASA Image -ISS014E18811: Astronaut Suni Williams, Expedition 14 flight engineer, works with the Lab-on-a-Chip Application Development-Portable Test System (LOCAD-PTS) experiment in the Destiny laboratory of the International Space Station. LOCAD-PTS is a handheld device for rapid detection of biological and chemical substances onboard the station.+ View Larger Image
NASA Image: ISS015E08353 - Lab-On-a-Chip Application Development Portable Test System (LOCAD-PTS) experiment hardware in the U.S. Laboratory/Destiny during Expedition 15.+ View Larger Image
Information Provided and Updated by the ISS Program Scientist's Office