Researchers at Northwestern Medicine have developed an innovative range of bioactive ‘tissue papers’ that have potential for use in regenerative medicine and tissue engineering.
The tissue papers are made from structural proteins derived from organs, which retain the properties of the organ from where the proteins came. The proteins are naturally excreted by cells and help to give organs their structure. When those proteins are combined with a polymer, they can be formed into tissue papers that are thin, flexible and can be folded and shaped as required.
The researchers created different tissue papers using structural proteins from different organs, using structural proteins from ovaries, kidneys, the liver, muscles, hearts and uterine tissue. Each tissue paper retained the cellular properties of the tissue from which it was derived.
The material can be folded, rolled or cut into the required form. It is surgically friendly and can be sutured into tissue. The researchers demonstrated how easy the material is to use by using it to create an origami bird. The tissues can still be rolled, folded and manipulated when wet.
The tissues were discovered to support the growth of adult stem cells. The researchers obtained stem cells from human bone marrow, placed them on the tissue paper, and after four weeks the stem cells had attached and multiplied. Adam Jakus, first author of the study, said “It’s an indicator that once we start using tissue paper in animal models it will be biocompatible.”
The potential of the new biomaterials is considerable. They could be used by surgeons to aid wound healing. Co-author of the paper, Ramille Shah, believes the material could support cell signaling and could accelerate the healing process and prevent scarring. The tissues derived from ovaries have been used to grow ovarian follicles, which went on to mature and produce hormones. The researchers say these tissues could be used to help cancer patients recover their hormone function after chemotherapy.
The tissue was first made by accident. Jakus said he was attempting to make a 3D printable ovary ink, when he accidently spilled the ink. When he tried to wipe up the spill he found that it had formed a dry sheet. He said he immediately realized the potential of the material. Jakus said, “I knew right then I could make large amounts of bioactive materials from other organs. The light bulb went on in my head. I could do this with other organs.”
To make the tissue papers, cells are removed from tissues, leaving behind the extracellular matrix. That is then dried and processed into a powder, which is combined with a polymer and processed into the tissue papers. Since each tissue paper has the same protein architecture and biochemicals from the cells from which it is derived, it can stimulate cells to behave in a certain way.
The paper – Tissue Papers” from Organ-Specific Decellularized Extracellular Matrices – has recently been published in the journal, Advanced Functional Materials.