Biomedical Engineering Reference
In-Depth Information
polyethersulfone (PES) coated with bone-like apatite also show bonding of the implant to
native bone, accompanied by remodeling and complete resorption of the apatite layer after
30 weeks (Nagano et al. 1996). Thus, a variety of biomimetically mineralized polymer scaf-
folds have utility in bone tissue engineering.
While these BLM coatings mimic the mineral component of bone, they can be altered to
include biomolecules such as proteins, growth factors, enzymes, and nucleic acids within
the biomineral layer, resulting in organic/inorganic hybrid biomaterials that have the
potential to dictate cellular events in an even more controlled manner.
Organic/InorganicHybrids
Native bone is a composite material consisting of both inorganic and organic phases. The
organic components play important roles in the nucleation and formation of mineral,
while influencing osteogenic growth and differentiation. Incorporation of organic mol-
ecules such as proteins, growth factors, and DNA into BLM coatings gives rise to a new
class of organic/inorganic hybrid materials. These composites are capable of influencing
mineral growth and are also able to enhance cell attachment and direct these adhering
cells toward osteogenic differentiation. Using different combinations of biomolecules and
mineralization regimens, it is possible to mimic physiologic spatial and temporal gradients
of bioactive molecules to modulate cellular function and bone formation during develop-
ment, repair, and regeneration. Other applications of organic/inorganic hybrids include
a) Adsorption of biomolecule on BLM coating
c) Adsorption and coprecipitation of biomolecules
Peptide/protein/DNA
BLM with protein/DNA
BLM
PLGA
b) Coprecipitation of biomolecules into BLM coating
d) Adsorption and coprecipitation with multiple
BLM layers
Peptide/protein/DNA
BLM with protein/DNA
PLGA
FIGURE 1.2
Schematic representation of cell substrate interactions with several variations of organic/inorganic hybrid con-
structs. (a, c) Cells binding to biomolecules that have been adsorbed, (b, d) demonstrate cellular interactions
with adsorbed and/or coprecipitated moieties. Peptides in panels a, c, d aim to anchor the cells to the substrate
surfaces while exposing basal surface for uptake of growth factors and DNA.
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