Biomedical Engineering Reference
In-Depth Information
images is used in the design of scaffolds having anatomical correct shape and size.
Cells are cultured in vitro and encapsulated into the photopolymerizable polymer so-
lution while also growth factors are added into the mixture. With a RP technique, the
scaffold is produced under UV light. The cellular scaffold is dynamically conditioned
in vitro with a bioreactor. The tissue engineered OC construct is then implanted into
the OC defect of the patient.
In another study by Schek et al. [
113
], a biphasic poly-L-lactic acid/HAp compos-
ite scaffolds for OC tissue engineering were developed bymeans of a RPmethod with
image-based design, which resulted in scaffolds with a matched articular shape and
load bearing features. The polymeric phase was seeded with chondrocytes whereas
fibroblasts transduced with an adenovirus expressing BMP-7 was introduced into the
HAp part. The subcutaneous implantation of the constructs into mice demonstrated
the potential of this strategy for OC tissue regeneration.
Lima et al. [
114
] used finite element modelling to study the biophysical stimuli
occurring within the structure under dynamic deformational loading. They developed
bilayered OC constructs composed of a cell-seeded agarose gel on the top and a bone
part at the bottom where in the middle an interface region of gel/bone was formed.
The results showed that relatively more inhomogeneous mechanical signals, such as
strain, fluid flowor fluid pressure, occurredwithin the gel region of theOC composite,
compared to the structures only made of gel. That study showed that the cells in the
gel may sense these radially and axially varied signals, and it may be beneficial to
achieve an inhomogeneity in engineered OC constructs.
2.6 Final Remarks
TERM is a truly multidisciplinary field with the ultimate goal of regenerating dam-
aged/diseased tissues. Several strategies are available for cartilage and bone tissue
regeneration. However, the gold standard does not exist. Many factors affect the out-
come of the strategies: the type and manufacturing technique of biomaterials, source,
type and culturing conditions of cells, employment of growth factors and bioreactors,
and their cumulative effect when used in combination. It is also noteworthy that the
depth and size of the lesion, and the patient's age and condition affect the repair re-
sponse. As herein discussed, many options exist for each of the components of tissue
engineering. Each strategy has its own advantages and disadvantages. Nevertheless,
the new generation strategies of TERM show the trend to be patient-specific and to be
built on a multiscale approach, specially benefiting from basic science, engineering,
and medical imaging and modelling.
Acknowledgments
The authors thank the financial support of the MultiScaleHuman project (Con-
tract number: MRTN-CT-2011-289897) in the Marie Curie Actions—Initial Training Networks.
