Engineered in vitro

A new pathway was recently engineered in vitro employing purified His6-tag-ged PhaCl and PhaC2 from P. aeruginosa plus a commercially available acyl-CoA synthetase allowing in vitro de novo PHA granules and in vitro synthesis of poly(3HD) from 3-hydroxydecanoate [74]. 

Freed, L.E., Martin, I., and Vunjak-Novakovic, G. (1999) Frontiers in tissue engineering In vitro modulation of chondrogenesis. Clin. Orthop. Relat. Res. 367S, S46-S58... 

An alternative approach to broaden the availability of immunocompatible cells is to use stem cells that have the potential to differentiate into various cell types and also can be genetically manipulated because of their inherent self-renewal property. Thus, one could hope for the availability of functionally replaceable tissues off the shelf. Efficacy of using stem cells has been clinically proven beneficial in treating a variety of blood-related disorders. Furthermore, plasticity of stem cells has also been demonstrated in various animal models, suggesting that stem cells from one tissue type can be converted into cells of other tissues as well for example, when bone marrow cells were transplanted into liver-injured animals, these cells restored the liver by differentiating into liver cells. However, there is a need to engineer in vitro systems that can provide various microenvironments conducive to drive stem cells to defined cell types and then colonize them to generate needed tissue parts. 

Weber, K. S., Donermeyer, D. L., Allen, P. M. and Kranz, D. M. (2005) Class II-restricted T cell receptor engineered in vitro for higher affinity retains peptide specificity and function. Proc Natl Acad Sci U S A 102, 19033-19038... 

Figure 4.1 Comparison of traditional and cell-free metabolic engineering, (a) Desired biochemical pathway, (b) Methodology for metabolic engineering in vivo, (c) Methodology for metabolic engineering in vitro.

M.S. Peach, et al., Polyphosphazene functionalized polyester fiber matrices for tendon tissue engineering in vitro evaluation with human mesenchymal stem cells, Biomed. Mater. 7 (4) (2012) 045016. 

Isenberg BC, Williams C, Tranquillo RT, Small-diameter artificial arteries engineered in vitro. Circ Res, 2006, 98, 25-35. 

Thus, delivery of veaors encoding for spedfic proteins dther alone or in combination guiding cellular behavior represents a very promising tool to further enhance tissue regeneration/engineering in vitro as well as in vivo. 

Larkin, L.M., Calve, S., Koshominova, T.Y., Arruda, E.M. Structure and functional evaluation of tendon-skeletal muscle constructs engineered in vitro. Tissue Engineering 12, 3149-3158 (2006)... 

Amadori, S., Torricelli, P., Panzavolta, S., ParriUi, A., Fini, M., Bigi, A., 2015. Multi-layered scaffolds for osteochondral tissue engineering in vitro response of co-cultured human mesenchymal stem cells. Macromol. Biosci. 15 (11), 1535—1545. 

Larkin, L.M., Van DerMeulen, J.H., Dennis, R.G., Keimedy, J.B., 2006. Functional evaluation of nerve-skeletal muscle constructs engineered in vitro. In Vitro Cell Dev. Biol. Anim. 42, 75-82. 

Park, H., Radisic, M., Lim, J. O. et al. 2005. A novel composite scaffold for cardiac tissue engineering. In Vitro Cell Dev Biol Anim 41 188-96. 

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