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tissue engineering

Saturday 23 April 2005

Tissue engineering was once categorized as a sub-field of biomaterials, but having grown in scope and importance it can be considered as a field in its own right.

Tissue engineering is the use of a combination of cells, engineering and materials methods, and suitable biochemical and physio-chemical factors to improve or replace biological functions.

While most definitions of tissue engineering cover a broad range of applications, in practice the term is closely associated with applications that repair or replace portions of or whole tissues (i.e., bone, cartilage, blood vessels, bladder, skin etc.).

Often, the tissues involved require certain mechanical and structural properties for proper functioning.

The term has also been applied to efforts to perform specific biochemical functions using cells within an artificially-created support system (e.g. an artificial pancreas, or a bioartificial liver).

The term regenerative medicine is often used synonymously with tissue engineering, although those involved in regenerative medicine place more emphasis on the use of stem cells to produce tissues.

A commonly applied definition of tissue engineering, as stated by Langer and Vacanti, is "an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ".

Tissue engineering has also been defined as "understanding the principles of tissue growth, and applying this to produce functional replacement tissue for clinical use."

A further description goes on to say that an "underlying supposition of tissue engineering is that the employment of natural biology of the system will allow for greater success in developing therapeutic strategies aimed at the replacement, repair, maintenance, and/or enhancement of tissue function."

Powerful developments in the multidisciplinary field of tissue engineering have yielded a novel set of tissue replacement parts and implementation strategies.

Scientific advances in biomaterials, stem cells, growth and differentiation factors, and biomimetic environments have created unique opportunities to fabricate tissues in the laboratory from combinations of engineered extracellular matrices ("scaffolds"), cells, and biologically active molecules.

Among the major challenges now facing tissue engineering is the need for more complex functionality, as well as both functional and biomechanical stability in laboratory-grown tissues destined for transplantation.

The continued success of tissue engineering, and the eventual development of true human replacement parts, will grow from the convergence of engineering and basic research advances in tissue, matrix, growth factor, stem cell, and developmental biology, as well as materials science and bio informatics.

Bottom-up tissue engineering technologies address two of the main limitations of top-down tissue engineering approaches: the control of mass transfer and the fabrication of a controlled and functional histoarchitecture.

These emerging technologies encompass mesoscale (e.g. cell sheets, cell-laden hydrogels and 3D printing) and microscale technologies (e.g. inkjet printing and laser-assisted bioprinting), which are used to manipulate and assemble cell-laden building blocks whose thicknesses correspond to the diffusion limit of metabolites, and present the capacity for cell patterning with microscale precision, respectively.

Reports

In 2003, the NSF published a report entitled "The Emergence of Tissue Engineering as a Research Field", which gives a thorough description of the history of this field.

Links

- UMIST

Open references

- Tissue engineering tools for modulation of the immune response. Boehler RM, Graham JG, Shea LD. Biotechniques. 2011 Oct;51(4):239-54. PMID: 21988690 [Free]

- Tissue engineering of the urinary bladder: current concepts and future perspectives. Petrovic V, Stankovic J, Stefanovic V. ScientificWorldJournal. 2011 Jul 28;11:1479-88. PMID: 21805017 [Free]

References

- Griffith LG, Swartz MA. Capturing complex 3D tissue physiology in vitro. Nat Rev Mol Cell Biol. 2006 Mar;7(3):211-24. PMID: 16496023

- Bioconjugation of hydrogels for tissue engineering. Jabbari E. Curr Opin Biotechnol. 2011 Oct;22(5):655-60. PMID: 21306888