Cytograft Tissue Engineering, Inc. has developed a novel regenerative medicine platform called Tissue Engineering by Self-Assembly™, or TESA™. The TESA™ family of biomaterials is unique in that they provide high mechanical strength and long durability without relying upon synthetic scaffolding. TESA™ biomaterials are completely biological, and comprised exclusively of cultured cells and extracellular matrix proteins assembled by the cells. Since there are no synthetic scaffolds or chemical fixation/modification, the material is non-immunogenic and non-inflammatory.
The TESA™ platform includes three independent approaches: Sheet-based Tissue Engineering™ (SBTE), Thread-based Tissue Engineering™, and Particle-based Tissue Engineering™. Used alone or in combination, these materials provide basic building blocks from which more complex three dimensional tissue constructs and organs can be built.
Sheet-based Tissue Engineering™
In Sheet-based Tissue Engineering (SBTE), adherent cells such as fibroblasts or mesenchymal stem cells are cultured for prolonged periods of time in conditions that promote the production of extracellular matrix proteins such as collagen. After several weeks in culture, the cells become embedded a complex milieu of well-organized matrix proteins. These proteins provide sufficient strength such that the sheet can be detached from the cell culture substrate and then stacked, rolled, folded, molded or cut into different configurations. The Lifeline™ vascular graft, for example, is built by rolling a sheet around a temporary support mandrel and then culturing the multi-laminate roll in a bioreactor so that the individual plies fuse to create a cohesive tissue. Single layer tissues such as heart valve leaflets can be produced by a combination of cutting and folding, giving the tissue different mechanical properties both regionally and directionally. Simpler tissues such as patches for soft tissue reinforcement can be produced by stacking sheets. In each case, the process is amenable to secondary manipulations such as decellularization or sterilization, or inclusion of drugs or specialized cell types.
Thread-based Tissue Engineering™
A similar approach can be used to manufacture cell-synthesized threads. In Thread-based Tissue Engineering™ (TBTE), adherent cells are cultured in conditions that promote a similar matrix-rich biomaterial, but in long ribbons that can be used directly or processed into threads. While the biological makeup of the biomaterial is essentially identical to SBTE™, the different configuration allows for very different assembly strategies such as weaving, braiding, or knitting. Strong patches or ligaments, for example, can be woven for soft tissue reinforcement or orthopedic applications. The threads can also be used as a stand-alone device to provide a completely biological suture for example.
Particle-based Tissue Engineering™
The TESA approach can also be used to create small particles that can be injected as an ECM-rich slurry or molded into microchanneled structures. These particles provide an ideal carrier for different cell- or drug-delivery strategies. The particles can also be used for different aesthetic applications, for example, to provide a non-inflammatory, durable dermal filler.