ABSTRACT
One primary goal of current biomaterials research and development is to provide permanent or temporary scaffolding materials or implants for tissue functional regeneration. Approaches often require tissue-implant integration, with intimate cellsurface attachment, migration, and proliferation desired immediately upon implantation. This is not as simple as might be expected from a survey of the multitude of basic cellsurface adhesion studies that abound in the literature, showing cell-surface interactions. Four decades of cell culture work on various substrates (metals, ceramics, polymers) have provided a wealth of knowledge about how numerous cell types recognize, attach, and proliferate on surfaces. Proteins, surface chemistry, topology, culture conditions and cell lineages are well-studied components of classical quasi-planar, two-dimensional culture conditions. However, one look at “real” cell culture environments in vivo places the stark contrast of in vitro culture conditions versus physiological tissue-or organ-based cell culture into context. Cell adhesion, recognition, and proliferation in a physiological environment proceeds under conditions quite distinct from those typically supplied in vitro. While appreciation of these details is important, the true challenge relevant to the biomaterials field and to tissue engineering strategies in particular is associated with duplication, maintenance, and preservation of long-term cell behavior in a context of functional tissue regeneration and, typically, an array of biomaterials. Tissue engineering aspects of organ architecture, mass transport, and three-dimensional structure are coupled with preservation and control of cell phenotype, cell growth and motility, constant and dynamic cell-cell communication, coexistence of multiple cell types in coordinated spatial relationships, and, ultimately, consistent expression of distinct cell behaviors to facilitate duplication of tissue function over longterm periods-hopefully, a human lifetime.
