Kennedy Space Center Fixation Tube (KFT) - 01.09.14
Science Objectives for Everyone
The Kennedy Space Center Fixation Tube (KFT) is an apparatus designed to contain plant or other small biological samples during flight and chemically fix and stain the tissue samples while providing three safety-levels of containment.
Science Results for Everyone
The Kennedy Space Center Fixation Tube (KFT), which carries and chemically fixes biological samples in space, holds promise for future molecular biological experiments. It uses a triple-redundant sealed environment for chemical fixatives extremely hazardous to humans. In a plant investigation using RNALaterTM sample preservative, the KFT resulted in better preservation. Onboard modifications also enhanced KFT’s functionality and storage potential in support of a plant gene-expression investigation. The KFT quickly preserves samples, holds potential for long-term storage without compromising RNA integrity, and offers simplified stow and descent procedures. KFTs filled with RNALaterTM can be deployed months or possibly years prior to use.
Kennedy Space Center, Space Life Sciences Laboratory, Cape Canaveral, FL, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
December 2001 - March 2010
Previous ISS Missions
The KFT has been utilized by investigations on ISS Increment 4 (PESTO), 16 and 17 (CWRW).
- The Kennedy Space Center Fixation Tube (KFT) is a device for chemical fixation of a biological sample in microgravity.
- It is small and easy to use, and is well suited to use in the field as well as in the laboratory.
- Because typical chemical fixatives are extremely hazardous to humans, the device is also designed to contain its fixative solution within a triply-redundantly sealed environment.
The KFT provides three levels of containment for the chemical fixative during stowage and operations. The KFT is comprised of the following elements: a polycarbonate main tube where fixative is loaded preflight, the sample tube which is used to keep the plant or other specimen in place during operations, the expansion plug, top plug, base plug, and the plunger. The KFT contains approximately 35 ml of fixative solution and provides a usable sample volume of either 25 or 41 ml depending on which of the current two configurations is employed. KFTs have proven to provide very robust containment. The KFT has been demonstrated to maintain its containment at ambient temperatures, +4 degrees C refrigeration, and -99 degrees C freezing.
The KFT has been shown to be compatible with many fixative reagents. Some of the tested reagents are listed below:
- 100 percent RNAlater
- 0.4 percent Formaldehyde (0.4 percent)
- 5 percent formalin, 5 percent acetic acid, 50 percent ethanol
- 0.5 percent Glutaraldehyde, 2 percent Paraformaldehyde
- The KFT includes a main tube, sample tube, expansion plug, base plug, and top-plug/plunger assembly.
- Prior to use, the fixative solution is contained at the bottom of the main tube, below the expansion plug. The sample is placed in the sample tube, which is then inserted in the main tube and sealed in the main tube by inserting the top plug.
- Next, the plunger is used to actuate a mechanism that loosens the seals on the expansion plug, then push the sample tube down against the sample plug, thereby pushing the sample into the fixative solution.
When conducting biological studies, it is important to maintain the integrity of the samples. The standard method to preserve samples is quick freezing at low temperatures, -80º C (-112º F) and below, but strict temperature control of samples on station is not always uniform or possible. Therefore, a preservation method is needed that will maintain the integrity of biological samples. In conjunction with the KFT, RNALaterTM was used to preserve some of the PESTO samples on station during increment 4. Results indicated that the method utilized resulted in a sample which was better preserved for future analysis (Paul 2005).
Certain modifications of the KFTs were designed to enhance on orbit functionality and storage potential in support of the TAGES (Transgenic Arabidopsis Gene Expression System) investigation. The KFT main tube was shortened allowing it to fit into certain areas and changes to the actuator mechanism and the expansion plug mechanism were made to create a more reliable system. Analysis of the returned TAGES samples was performed and determined that the RNA integrity was very good. The KFT device is extremely valuable because it quickly preserves harvested samples, it holds potential for long term storage without compromising the RNA integrity and because it does not require specific temperature regulations, destow and descent procedures have been simplified. We also established that KFTs filled with RNALaterTM can be effectively deployed to orbit months or possibly years prior to use. Utilizing KFT devices creates a large window of opportunities for future molecular biological experiments (Ferl 2011).Results Publications
Paul A, Levine HG, McLamb W, Norwood KL, Reed DW, Stutte GW, Wells HW, Ferl RJ. Plant molecular biology in the space station era: Utilization of KSC fixation tubes with RNAlater. Acta Astronautica. 2005; 56: 623-628.
Ferl RJ, Zupanska AK, Spinale A, Reed DW, Manning-Roach S, Guerra G, Cox DR, Paul A. The performance of KSC Fixation Tubes with RNALater for orbital experiments: A case study in ISS operations for molecular biology. Advances in Space Research. 2011; 48(1): 199-206. DOI: 10.1016/j.asr.2011.03.002.
Ground Based Results Publications
- KSC Fixation Tube Biocompatibility Study Using Caenorhabditis elegans
- Life Science Services Contract
- NIH BioMed-ISS Meeting Video Presentation, 2009?KFT
- NIH BioMed-ISS Meeting, 2009?KFT
KSC Fixation Tube. Image courtesy of http://www.lssc.nasa.gov/fs/lsda/.
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