NASA has patented a new technology that may prevent the rejection of transplanted cells and tissues. The human immune system identifies and rejects non-host cells and tissues with high efficiency. The new invention involves the fabrication and use of carbon nanotube buckypaper (CNTBP) “cages” for immune shielding. This approach promotes and supports a variety of useful biological processes that are difficult or impossible when cells or tissue are maintained in culture outside the body. It allows for the transplantation of cells or tissues from unrelated donors or from unrelated species (xenografts) into host subjects with dramatically reduced potential for rejection and/or the use of immunosuppressive therapies, which can be highly toxic. Current strategies for islet cell transplantation, for example, have shown marginal success due to limited graft survival, even with immunosuppressive therapy.
The buckypaper cage concept provides construction of one or more cages, envelopes, enclosures, or receptacles (referred to collectively herein as a “cage”) made primarily of CNTBP, and is a strategy for transplanting multiple types of cells and tissue in various applications and environments. The biological material is placed in a structure — a cage — that promotes desirable characteristics like immune shielding, physical structure, porosity, and biocompatibility. The innovation can also be used to provide a microenvironment (within the human or other host body), in which temperature, pH, oxygen levels, carbon dioxide levels, nutrient levels, metabolite levels, and levels of cytokines and other regulatory molecules (including molecules that may not be characterized) are optimum to permit differentiation of cells or the assembly of tissue structures for later use in tissue engineering applications. The immune shield cage can also be configured to perform sensing and secretion functions, where certain molecules trigger the release of desired substances and control the biological functioning of the material inside the cage. Chemical modification of the cage material is also possible in order to suit the particular environment or application, and to obviate the need for immunosuppressive drugs.
Specific benefits include biocompatibility, an ease of engineering to create a variety of shapes and forms, and cage material that allows the cells and tissue to be maintained in a live and functioning state. The cage material is also flexible and resilient and does not provoke an immune response, does not elicit scar formation, and resists protein deposition. This innovation allows for the ability to control the dimensions of the cage, and optimizes the transport of metabolic substances into and out of the cage.
This work was done by David Loftus of Ames Research Center. NASA invites companies to inquire about partnering opportunities and licensing this patented technology. Contact the Ames Technology Partnerships Office at 1-855-627-2249 or