Stem Cell Differentiation Depending on Different Surfaces - Tissue Engineering: Cell-Surface Interactions for Tissue Culture - page 266

9000

8499

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7534

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6385

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5361

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2414

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5 1 6 6 102134 176 221 305 455 668 3 6

01244444 01 2 2 0

0

Fig. 1 Cumulative number of publications over the last two decades dealing with biomaterial
and tissue engineering (entries in PubMed with the terms ''biomaterial'' and ''tissue engineering''
until December 2010)

orientation, adhesion, contraction, maturation, and the synthesis of ECM
components. After transplantation, the main function of the matrix in vivo is to
provide mechanical support until the newly formed tissue assumes this role [ 16 ].
Therefore, it is important to adjust the biomaterial properties as precisely as
possible [ 17 ]. The biomaterial features which have a huge impact on cell differ-
entiation are the surface charge, the substructure, the mechanical properties of the
material, and the degradation kinetics [ 17 ].
In a healthy tissue, cell differentiation is controlled by various environmental
factors of the cell surroundings, such as interstitial body fluids, fibrous tissue,
muscles, and tendons as well as the skeleton, which serve together as a natural
matrix [ 18 ]. The selection of an artificial biomaterial for in vitro cultivation and
differentiation is often a critical parameter. For tissue engineering applications,
four groups of biomaterials have been studied intensively [ 19 ] (Table 1 ).
However, naturally derived biomaterials often lack the mechanical strength
required by certain tissues, such as bone [ 7 ]. Other disadvantages are the relatively
low availability of these materials and their batch-to-batch variation [ 16 ].
Synthetic inorganic materials, such as b-tricalcium phosphate and hydroxyapatite
(HAP), have often been used to engineer hard tissue matrices [ 20 ]. These materials
are considered to be osteoinductive as their surface supports osteoblastic adhesion,
growth, and differentiation [ 7 ]. But the rather brittle behavior of pure synthetic
inorganic materials led to the fabrication of composite materials [ 21 ], which
combine synthetic inorganic materials with naturally derived components [ 22 ]
( Sect. 4.5 ).