BIOCERAMIC SCAFFOLD—BONE TISSUE ENGINEERING - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 90

Molecularandcellularinteractiononcalciumphosphate3Dscaf-
folds has been reviewed by several investigators. 27 - 31 They have
superior properties for the stimulation of bone formation related to
theirspecificinteractions,suchasionicexchanges,superficialmole-
cular rearrangement, and cellular activity, with extracellular fluids
andcells.Bonetissueengineeringapproachesaresuccessfulinmost
of the clinical cases; however, the supply of oxygen and nutrients
to the cells in the inner part of the implanted scaffolds remains
a major concern, requiring additional investigations. 32 It has been
concluded by one study that the extracellular Ca 2 + and inorganic
phosphate (Pi) significantly influence the growth and osteogenic
differentiation of MSCs and the cellular effect of these ions
needs to be considered when designing or constructing scaf-
folds for bone tissue engineering with calcium phosphate ceramic
scaffolds. 33
4.5 Basic Questions in Bone Tissue Engineering
As already discussed, the basic requirements for bone tissue engi-
neering are a suitable matrix or scaffold, a requirement of specific
cellsthatinteractpositivelywiththescaffold,andtheintroductionof
propergrowthfactorsataproperconcentrationthatcaninducedif-
ferentiationofcellsintooesteoblasts—themostimportantproperty
beingthebiocompatibilityofthescaffoldbesidesitsabilitytobeuti-
lizedbyclinicians,thatis,howthescaffoldcanbesterilized,etc.The
scaffold should facilitate adhesion and proliferation of cells, in addi-
tion to extracellular matrix deposition, allowing tissue ingrowth. 34
An ideal scaffold material should be a 3D porous structure with
interconnected pores. It should be biodegradable but with a con-
trolled degradation rate with adequate mechanical strength. 1 Only
inorganic materials like calcium phosphates, HA, and glass ceram-
ics, along with a natural coralline HA matrix, have been identified
as potential bioceramic scaffold materials for applications in bone
tissue engineering. 35 Although HA and bioglass matrices are con-
sidered potential scaffolds, 36 , 37 the biodegradability of these mate-
rials is relatively slow. Modifications of these materials need to be
actively considered for improving their biodegradability. Composite