Microencapsulation Electrostatic Processing System (MEPS) - 11.22.16

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
A single step process forming a tiny liquid-filled, biodegradable, micro-balloon containing various drug solutions (a process called microgravity micro-encapsulation) has been shown to provide better drug delivery and new medical treatments for solid tumors and resistant infections. Recent testing in mouse models has shown that these unique microcapsules can be injected into human prostate tumors to inhibit tumor growth or can be injected following cryo-surgery (freezing) to improve the destruction of the tumors better than freezing or local chemotherapy alone. The microcapsules also contain a contrast agent that enables C-T, x-ray or ultrasound imaging to monitor the distribution within the tissues to ensure that the entire tumor is treated when the microcapsules release their drug contents.
Science Results for Everyone
These experiments seek to create microcapsules or tiny balloons to deliver drugs to specific targets in the body. This study looked at various methods to mix dissimilar liquids to form microcapsules, which were analyzed for size and drug content. Researchers also analyzed the effects of temperature and internal pressure on the size of the capsules. In ground-based medical investigations, these microcapsules inhibited growth of human prostate and lung tumors with a few local injections. Injecting anti-cancer microcapsules following cryo-surgery can completely destroy small tumors in just three weeks. This microencapsulation electrostatic processing system and resulting technologies have been awarded patents.

The following content was provided by Dennis R. Morrison, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
Dennis R. Morrison, Ph.D., Johnson Space Center, Houston, TX, United States

Information Pending

Information Pending

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

Research Benefits
Information Pending

ISS Expedition Duration
June 2002 - December 2002

Expeditions Assigned

Previous Missions
STS-95 and Increment 5

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Experiment Description

Research Overview

  • Microencapsulation Electrostatic Processing System (MEPS) was used to produce microcapsules.
  • These unique capsules, which resemble miniature liquid-filled balloons the size of blood cells, are designed to deliver FDA-approved anti-cancer drugs by injection into the blood stream targeting infected organs.
  • The microgravity environment on the International Space Station (ISS) is vital to the development of these capsules. This environment enables the pharmaceutical and its outer member to spontaneously form.

The microcapsulation electrostatic processing system (MEPS) is an automated system that is used to produce liquid-filled micro-balloons. It works through the use of microcapsules, unique capsules resembling miniature liquid-filled balloons the size of blood cells, that deliver FDA-approved anti-cancer drugs by injection into the bloodstream. The microgravity environment on ISS is vital to the development of these capsules because the station environment enables the pharmaceutical and its outer membrane to form spontaneously.

MEPS was designed with flexibility in mind. The system can process a wide range of experiments. For example, it can handle volumetric proportions of up to six chemical constituents; it can transfer liquids back and forth, at variable rates, between its six reservoirs and two main chambers; it can apply different electrical fields to the enclosed experiments; and it can be programmed to use filters or membranes of different porosity between chambers. Electrical fields charge the surface of the microcapsules, making it less recognizable as a foreign invader to the immune system.

The use of microcapsules will benefit the treatment of several diseases. For example, to eliminate daily insulin shots diabetes patients can use implanted microcapsules as treatment. A further Earth application is the microcapsules can be used as a substitution for chemotherapy. Traditional anti-cancer treatment involves large quantities of drugs that affect the entire body. The microcapsules contain a smaller dose of medication that directly targets tumors. Also, they reduce the unwanted side effects currently produced by chemotherapy.

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Space Applications
Expanding our understanding of the use of microgravity to enable development of new drug delivery devices which can protect astronauts on long-duration space missions and provide alternative delivery routes and countermeasures to injured or sick crew members.

Earth Applications
The utilization of microcapsules will benefit the treatment of several diseases here on Earth. Microcapsules can be inhaled to delivery antibiotic and immune stimulant drugs to treat inhaled bacterial infections of the lungs. These unique microcapsules can be injected directly into solid tumors to provide local, sustained release, of anti-cancer drugs. The microcapsules can be imaged with C-T scans or ultrasound to insure that the release combinations of medications slowly over 12-14 days which can be delivered directly to the target tumors. Since the drug release is local, using these microcapsules reduces the unwanted side effects of systemic (intravenous) chemotherapy, which involves large amount of drugs producing major side effects throughout the entire body.

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Operational Requirements and Protocols
EXPRESS Rack 1, locker 5 supplies MEPS with power, video, and computer support. MEPS requires less than 15 minutes of crew time to set up and initiate an experiment.
To initiate the MEPS experiments the crew installs the pre-programmed PC-MCIA card into the front control panel. They unstow and insert a PCM (experiment), which was pre-loaded with chemical fluids before flight, into the Experiment Module, and then activate the experiment which runs automatically for approximately two hours. At the end of the run, the MEPS automatically powers down to await later removal of the PCM for stowage until it is returned to Earth. Real-time data is recorded for post-flight analysis. The crew may also monitor the fluid flows and microencapsulation process via the video display on the front panel.

While MEPS will remain on orbit past Increment 6, the Shuttle will return used PCMs and video tape to Earth and deliver new PCMs, PC-MCIA cards, and videotapes for future experiments.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

MEPS experiment on ISS consisted of eight samples processed using various methods to mix dissimilar liquids to form micro-balloons/microcapsules. The recovered micro-balloons were analyzed for size and drug content. Additionally, studies included the effects of temperature and mixing fluid shear on the size of the micro-balloons and payload concentration of contrast and concentrated drug.  During this investigation several combinations of anti-cancer drugs, photodynamic therapy drugs, and a DNA construct were successfully encapsulated. These results led to the invention and NASA Patent for a Pulse Flow Microencapsulation Processing System that has been used to make these microcapsules for ground-based studies on human tumors grown in a mouse model. Preclinical investigations revealed that when only a few doses of microcapsules containing 5-fluorouracil (5-FU) are injected directly into human prostate tumors, the growth can be inhibited by up to 51% within 3 weeks. When chemotherapy microcapsules are injected following cryosurgery, the combined treatment can greatly inhibit the growth of  1-2cm size prostate tumors by 72%  in just three weeks (Morrison 2009). Other studies using 2 doses of 5-FU microcapsules injected into A549 human lung tumors inhibited growth by 45% and destroyed 18% of the lung tumors after 4 weeks of sustained release. In a parallel study, only two doses injected of microcapsules containing Paclitaxel, injected on Day 0 and Day7 produced macroscopic necrosis in 43% of the tumors. After 26 days of sustained Paclitaxel release, lung tumor growth was inhibited by 82% and 28% of the tumors had completely disappeared.

A further study was carried out aiming to confirm the increased growth inhibition of human prostate tumors produced by an intentionally palliative combination treatment of cryochemotherapy (partial cryoablation followed by intratumor partial chemotherapy with injection of microencapsulated 5-FU at the ice ball periphery). The results of this study extend and confirm previous findings (Le Pivert 2009). The addition of 5-FU focal chemoablation to partial cryoablation of a fast growing hormone resistant prostate cancer enhances the directional destructive effect of cryosurgery and inhibits growth in peripheral unfrozen tumor tissues (Le Pivert 2004).

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Results Publications

    Morrison DR, Haddad RS.  Microencapsulation of Drugs: New cancer therapies and improved drug delivery derived from microgravity research. 40th Space Congress, Cape Canaveral, FL; 2003

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Ground Based Results Publications

    Le Pivert PJ, Haddad RS, Aller A, Titus K, Doulat J, Renard M, Morrison DR.  Ultrasound Guided, Combined Cryoablation and Microencapsulated 5-Fluorouracil, Inhibits Growth of Human Prostate Tumors in Xenogenic Mouse Model Assessed by Fluorescence Imaging. Technology in Cancer Research and Treatment. 2004; 3(2): 135-142.

    Le Pivert PJ, Morrison DR, Haddad RS, Doulat J, Renard M, Aller A, Titus K.  Percutaneous tumor ablation: microencapsulated echo-guided interstitial chemotherapy combined with cryosurgery increases necrosis in prostate cancer. Technology in Cancer Research and Treatment. 2009; 8(3): 207-216. PMID: 19445538.

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ISS Patents

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Related Publications

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Related Websites
NASA Fact Sheet

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image Micro-balloons containing anti-tumor drugs and small amounts of radio-contrast oil were created during MEPS operations on STS-95. The radio-contrast oil is traceable by radiograph and allows doctors to follow the microcapsules as they travel to the tumor. The permeable outer skin releases the drug slowly, giving the microcapsule plenty of time to reach its destination. This slow release prevents artery damage as the drug travels to its destination. Image courtesy of NASA, Johnson Space Center.
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image The images shows some microcapsules produced on ISS in MEPS during the UF-2 mission (July 18-19,2002). Image courtesy of NASA, Johnson Space Center.
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image NASA Image: JSC2002E35992 - MEPS installed in Express rack #3.
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image NASA Image: JSC2002E35988 - MEPS front view.
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