Microencapsulation of anti-tumor drug research on ISS severely curtailed by Shuttle Termination

Cancer Treatment Delivery01.13.10
 
Microencapsulation containing anti-tumor drugs made on ISS. (Image credit: NASA)What was done on ISS: A single step process forming tiny liquid-filled, biodegradable micro-balloons containing various drug solutions (a process called microgravity micro-encapsulation) can provide better drug delivery and new medical treatments for solid tumors and resistant infections. 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 much 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 insure that the entire tumor is treated when the microcapsules release their drug contents.

The Microencapsulation Electrostatic Processing System-II experiment (MEPS-II), led by Dr. Dennis Morrison (retired) at NASA Johnson Space Center, was performed on ISS in 2002 and included innovative encapsulation of several different anti-cancer drugs, magnetic triggering particles, and encapsulation of genetically engineered DNA. The experiment system improved on existing microencapsulation technology by using microgravity to modify the fluid mechanics, interfacial behavior, and biological processing methods as compared to the way the microcapsules would be formed in gravity. In effect, the MEPS-II system on ISS combined two immiscible liquids in such a way that surface tension forces (rather than fluid shear) dominated at the interface of the fluids. The significant performance of the space-produced microcapsules as a cancer treatment delivery system (Le Pivert et al. 2004) motivated the development of the Pulse Flow Microencapsulation System (PFMS), which is an Earth-based system that can replicate the quality of the microcapsules created in space.

Single cell microencapsulation. (Image credit: NASA)Significance: As a result of this ISS research, the results from the MEPS-II experiments have provided new insight into the best formulations and conditions required to produce microcapsules of different drugs, particularly special capsules containing diagnostic imaging materials and triggered release particles. Co-encapsulation of multiple drugs and Photodynamic Therapy (PDT) drugs has enabled new engineering strategies for production of microcapsules on Earth designed for direct delivery into cancer tissues. Other microcapsules have now been made for treatment of deep tissue infections, clotting disorders, and to provide delivery of genetic engineered materials for potential gene therapy strategies (Morrison et al. 2003). Microcapsules that were made on ISS and that are targeted at inhibiting growth of human prostate tumors have been successfully dem¬onstrated in laboratory settings (Le Pivert et al. 2004, LePivert et al 2009).

Schematic of the Pulse Flow Microencapsulation System. (Image credit: NASA)Benefits of ISS Research: The microgravity environment on the ISS was an enabling environment that led the way to better methods of microcapsule development on Earth. Several NASA patents have issued from this space-based research and more are pending. Nu Vue Therapeutics, Inc. is one of several commercial companies that have licensed some of the MEPS technologies and methods to develop new applications, such as innovative ultrasound enhanced needles and catheters that will be used to deliver the microcapsules of anti-tumor drugs directly to tumor sites (see Morrison et al. 2003). Clinical trials to directly inject microcapsules of anti-tumor drugs into tumor sites will begin soon at MD Anderson Cancer Center in Houston and the Mayo Cancer Center in Scottsdale, AZ.

Other potential uses of this microencapsulation technology include: microencapsulation of genetically engineered living cells for injection or transplantation into damaged tissues; enhancement of human tissue repair; and, real-time microparticle analysis in flowing sample streams that would allow petrochemical companies monitor pipeline volume flow.

Patrick J. Le Pivert, MD, Dennis R. Morrison, Ph.D., Ruwaida S. Haddad, Ph.D., Michel Renard, Ph.D., Alex Aller, Ph.D., Kerry Titus, BS, Jacques Doulat, Ph.D. 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.