Fabricating tissues: Analysis of farming versus engineering strategies
- 103 Downloads
Tissue Engineering has expanded rapidly towards target applications of tissue repair and regeneration, whilst generating surprisingly novel models to study tissue modelling. However, clinical success in producing effective engineered tissues such as bone, skin, cartilage, and tendon, have been rare and limited. Problems tend to focus on how to stimulate the replacement of initial scaffold with mechanically functional, native extracellular matrix (principally collagen). Typical approaches have been to develop perfused and mechanically active bioreactors, with the use of native collagen itself as the initial scaffold, though the idea remains that cells do the fabrication (i.e. a cultivation process). We have developed a new, engineering approach, in which the final collagen template is fabricatedwithout cell involvement. The first part of this biomimetic engineering involves a plastic compression of cellular native collagen gels to form dense, strong, collagenous neotissues (in minutes). Further steps can be used to orientate and increase collagen fibril diameter, again by non-cell dependent engineering. This allows operator control of cell or matrix density and material properties (influencing biological half life and fate). In addition, this (non-cultivation) approach can incorporate techniques to generate localised 3D structures and zones at a meso-scale. In conclusion, the use of biomimetic engineering based on native collagen, rather than cell-cultivation approaches for bulk matrix fabrication, produces huge benefits. These include speed of fabrication (minutes instead of weeks and months), possibility of fine control of composition and 3D nano-micro scale structure and biomimetic complexity.
Keywordscollagen deposition plastic compression 3D meso-structure cell density fibril density biomimetic fabrication gel behaviour
Unable to display preview. Download preview PDF.
- 3.Bell, E., S. Sher, and B. Hull (1984) The living skin-equivalent as a structural and immunological model in skin grafting.Scan. Electron Microsc. 4: 1957–1962.Google Scholar
- 5.Foroughi, F. and R. A. Brown, Collagen incorporation rates into bulk tissue engineering scaffolds: the rate limiting step. (in prep).Google Scholar
- 6.Ahsan, T., A. C. Chen, L. Chin, V. W. Wong, R. A. Bank, N. Verzijl, R. L. Sah, and A. Ratcliffe (2003) Effects of long term growth on tissue engineered cartilage.49th Annual Meeting of the Orthopaedic Research Society. Paper #0309.Google Scholar
- 13.Cheema, U., C.-B. Chuo, P. Sarathchandra, S. N. Nazhat, and R. A. Brown, Engineering collagen scaffolds: Cyclical loading increases material strength and fibril aggregation. (submitted).Google Scholar
- 15.Frank, C., S. Woo, T. Andriacchi,et al. (1991) Normal ligament: structure, function and composition. pp. 45–101. In:Injury and Repair of the Musculoskeletal Soft Tissue, 2nd ed., American Academy of Orthopaedic Surgeons, Park Ridge, IL, USA.Google Scholar