Bioresorption and Degradation of Biomaterials - Tissue Engineering: Cell-Surface Interactions for Tissue Culture - page 328

collagen-like structures [ 106 ] as well as composite structures between ceramics
and polymers that mimic bone or teeth [ 107 ]. It is probably only a matter of time
before the properties of artificial materials surpass those of their natural prototype.
At present resorbable biomaterials are mostly used for the repair of diseased or
injured tissues, but other applications are already under discussion, such as drug
delivery nano-systems, biodegradable nano-robots, multi-functional particles,
biogalvanic batteries, and electronic components like sensors that dissolve and
disappear [ 108 - 114 ].
One of the next challenges will probably be to better understand the interface
between cell and material and to use this knowledge for the design of materials
tailored to specific cellular environments. So far, most of the research has con-
centrated on understanding how the physiological environment changes the
material. It seems at least as important to understand how the surrounding cells
react to the degrading material. It has long been known that cells react to the
surface properties of the materials they are attached to by changing their shape or
movement [ 115 ]. Recently it has also been shown that the differentiation of stem
cells is dependent on the elastic modulus of the material on which they are
cultivated [ 116 ]. At present, when a material is introduced into the body, an
unwanted foreign body reaction is principally expected. It can be envisioned,
however, that the right combination of materials combined with advanced 3D
design may one day lead to ''intelligent'' materials that can instruct stem cells to
build specific tissue geometries and degrade in the process, leaving only materials
that the cells can use to regenerate. To reach this distant goal a close collaboration
of cellular and molecular biologists with engineers, doctors and entrepreneurs will
be necessary.
Acknowledgments T.W. was supported by a grant from the German Federal Ministry of
Education and Science (BMBF, 16SV5057). M.M.M. is consultant to DePuy and Zimmer.
Institutional support was received from Ceramtec, Aesculap, DePuy, and Zimmer. No royalties.
A.F.S. has in the past 5 years provided consulting services to Biomet, Curasan, Eucro, Heraeus,
IPB, and Johnson & Johnson. No royalties.
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