Artificial ECMs

Lutolf MP (2009) Integration column artificial ECM expanding the cell biology toolbox in 3D. Integr Biol 1 235-241... 

In order to functionalize scaffolds to mimic the native cell environment, different strategies are available. Recombinant DNA technology can be used to design artificial ECM proteins to avoid the aforementioned complications that can arise with naturally derived materials [60], However, there is little known about the long-term... 

Fig. 1 Cellular (top left) and acellular (bottom left) tissue engineering approaches. Matrix materials are implanted into patient and act as an artificial ECM for cells to infiltrate, adhere, proliferate, and differentiate, and finally to guide repair and regeneration (modified from [5])...

Wang, J.L., Wang, L., Li, X., Mao, C.B., 2013a. Virus activated artificial ECM induces the osteoblastic differentiation of mesenchymal stem cells without osteogenic supplements. Sci. Rep. 3. 

The design of natural polymer-based artificial ECMs for liver tissue engineering is very important because the liver plays important roles in our body, such as metabolism, storage, and synthesis and release of carbohydrates, vitamins, lipids, proteins, and detoxification, inactivation of endogenous and exogenous substances and activation of precursor molecules (Zakim and Boyer, 1990). Also, hepatocytes as the parenchymal cells among liver cells are anchorage-dependent cells and the hepatocytes lose their fiver-specific functions and viability without an optimal artificial ECM (Chan et al., 2004). 

Seo et al. (2005) added xyloglucan (XG) as an artificial ECM into hepatocyte-encapsulated alginate MCs as the XG obtained from tamarind seed has galactose residues in the side chain. More than 70% of cultured hepatocytes in the alginate/XG scaffolds participated in spheroid formation after 2 days, whereas most hepatocytes in alginate MCs remained as a few aggregates even after 3 days as shown in Figure 6.7. 

Many research groups are attempting to construct artificial ECMs. The scaffolding for these matrices has taken the form of polymer materials that can be surface modified for desired functionalities. In some cases they are designed to be biodegradable allowing the cells to replace this material with its natural counterpart as they estabhsh themselves and their tissue function. The major obstacle is that the properties of this matrix are difficult to specify since the properties of natural ECMs are complex and not fuUy known. Furthermore, two-way communication between cells is difficult to mimic since the information contained within these conversations is also not fuUy known. At this time, the full spectrum of ECM functionahties can only be provided by the cells themselves. 

Scheme 1 Major aspects of the design of bio-artificial ECM mimics... 

The structure and composition of peptide amphiphiles are more flexible than those of amphiphilic-peptide. Designed to function as artificial ECM, peptide amphiphiles were in close connection with markers such as RGD in regenerative medicine. RGD is a peptide motif located on the chain of proteins present in the ECM and has been conjugated to a number of gelators to make synthetic and... 

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