Biomedical Engineering Reference
In-Depth Information
Nano-HA/collagen based scaffolds have now been successfully
used for thousands of cases in clinical applications, including all
the various types of hard-tissue repair. Yu
et al
.havereported64
cases of posterolateral fusion in patients from 46 to 79 years old.
In all cases the wound healed and no abnormity was found in local
and systematic examinations during long-term follow-up.
61
Neither
pseudoarthrosisnorcomplicationsofthepediclescrewsystemwere
found.Thesafetyofnano-HA/collagen/PLAcompositesusedinlum-
bar posterolateral fusion has already been proven. This study fur-
ther shows that use of this composite, combined with autologous
boneinposterolaterallumbarfusion,leadstoresultssimilartothose
found for autologous bone. The composites can thus be used as a
supplement to autologousbone.
22
CollagensusedintheseHA-collagencompositesarederivedfrom
animal tissues. They carry the risk of transmission of infectious
agents.
62
The recent development of recombinant protein expres-
sion technology provides a reliable, predictable, and chemically
defined source of purified, humanlike collagen multipeptide that is
free of animal components. Recombinant collagens have been pro-
duced by transfected cells.
63
-
71
Purified recombinant collagens are
capable of undergoing spontaneous alignment to form collagen fib-
rils and defined features that are characteristic of collagen. Recent
studies
72
,
73
haverevealedthatrecombinant,humanlikecollagenhas
thesamecharacteristicsintheinitialmineralizationstageasnatural
collagen. Additionally it also can induce the deposition and direct
the growth of HA nanocrystals
in vitro
in the form of self-assembly
of nanofibrils of mineralized collagen resembling an extracellular
matrix.
74
Theresearchonthenano-HA/recombinanthumanlikecol-
lagen/PLA(nHA/RHLC/PLA)scaffoldalsorevealedthatthescaffold
possessed good biocompatibility, biodegradation, and osteoconduc-
tivepropertyandthescaffoldmaintainedtheadvantagesofmineral-
izedanimal-sourcedcollagen,whileavoidingpotentialtransmission
of infection.
75
It is a promising material for bone tissue engineering
in the clinicalrepair of large bonydefects.
With the development of nano-HA/collagen scaffolds for bone
repair and regeneration, some advanced technologies and strate-
gie, such as electrospinning and stem cell technologies, are also
being introduced for the fabrication of bone-resembling material.
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