329
biopolymers diffi cult to handle. One of the crucial properties of the shark collagen
solution with Td of about 30 °C (Nomura et al. 1995 ), is that the dissolution of the
fi brillar gel obtained from this type of collagen takes place at 37 °C (Nomura et al.
2000a ). Correspondingly, this gel could not be practically used at the actual physical
temperature of human medical application. Similar situation is known with unstable
chum salmon collagen with the T d of approximately 19 °C (Matsui et al. 1991 ).
The development of bio-inspired collagen fi brillar gel from salmon, that served
only as a scaffold for cell culture has been demonstrated in several works (Yunoki
et al. 2003 , 2004 ; Nagai et al. 2007 , 2008a ). However, recently a chemical crosslinking method for improving the thermal stability of collagen gel derived from
chum salmon ( Oncorhynchus keta ) using water-soluble carbodiimide during in vitro
collagen fi brillogenesis, was reported (see for review Shen et al. 2008 ). The obtaining salmon collagen fi brillar gel has a denaturation temperature of 55 °C and showed
good biological properties in numerous in vitro studies. It was reported also about
the use of cross-linking agents like 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) during fi bril formation. This led to increases of the denaturation temperature in the fi sh collagen gels up to 47 °C (Kawaguchi et al. 2011 ).
To overcome the obstacle with low level of T d in fi sh collagens, a development of
the chitosan/marine-originated collagen composite has been recently reported
(Wang et al. 2010 ). In detail: “The chitosan gel including N-3-carboxypropanoil-6O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol%
and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with
the salmon atelocollagen (SA) gel at different mixture ratios. The SA gel fi rst,
within 2 weeks, and then chitosan in the composite gel was slowly absorbed after
implantation, followed by soft tissue formation. It is expected that this composite
gel will be available as a carrier for tissue fi ller and drug delivery systems,” (Wang
et al. 2010 ).
Collagen Scaffolds For the scaffold manufacturing, collagens originated from
marine products are indispensable due to severe infection problems from animal
source; such as bovine spongiform encephalopathy, avian and swine infl uenzas, and
tooth-and-mouth disease in bovine, pig, and buffalo that occur all over the world
(Hayashi et al. 2012 ). Three scaffold-design parameters are accepted as infl uencing
tissue regeneration: (i) modifi cation of scaffold surfaces to enhance cell interaction,
(ii) controlled release of growth factors from scaffolds, and (iii) scaffold mass transport (Hollister 2009 ).
Collagen scaffolds with excellent biocompatibility which were derived from
fresh water fi sh have been reported recently by Pati et al. ( 2012 ):
“The fi sh collagen scaffolds exhibited considerable cell viability and were comparable with that of bovine collagen. SEM and fl uorescence microscopic analysis
revealed signifi cant proliferation rate of cells on the scaffolds, and within 5 days the
cells were fully confl uent. These fi ndings indicated that fi sh collagen scaffolds
derived from fresh water origin were highly biocompatible in nature,” (Pati et al.
2012 ). Marine fi sh collagens are also known as good sources for designing tissue
scaffolds.
8.2 Fish Collagen as a Biomaterial
biopolymers diffi cult to handle. One of the crucial properties of the shark collagen
solution with Td of about 30 °C (Nomura et al. 1995 ), is that the dissolution of the
fi brillar gel obtained from this type of collagen takes place at 37 °C (Nomura et al.
2000a ). Correspondingly, this gel could not be practically used at the actual physical
temperature of human medical application. Similar situation is known with unstable
chum salmon collagen with the T d of approximately 19 °C (Matsui et al. 1991 ).
The development of bio-inspired collagen fi brillar gel from salmon, that served
only as a scaffold for cell culture has been demonstrated in several works (Yunoki
et al. 2003 , 2004 ; Nagai et al. 2007 , 2008a ). However, recently a chemical crosslinking method for improving the thermal stability of collagen gel derived from
chum salmon ( Oncorhynchus keta ) using water-soluble carbodiimide during in vitro
collagen fi brillogenesis, was reported (see for review Shen et al. 2008 ). The obtaining salmon collagen fi brillar gel has a denaturation temperature of 55 °C and showed
good biological properties in numerous in vitro studies. It was reported also about
the use of cross-linking agents like 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) during fi bril formation. This led to increases of the denaturation temperature in the fi sh collagen gels up to 47 °C (Kawaguchi et al. 2011 ).
To overcome the obstacle with low level of T d in fi sh collagens, a development of
the chitosan/marine-originated collagen composite has been recently reported
(Wang et al. 2010 ). In detail: “The chitosan gel including N-3-carboxypropanoil-6O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol%
and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with
the salmon atelocollagen (SA) gel at different mixture ratios. The SA gel fi rst,
within 2 weeks, and then chitosan in the composite gel was slowly absorbed after
implantation, followed by soft tissue formation. It is expected that this composite
gel will be available as a carrier for tissue fi ller and drug delivery systems,” (Wang
et al. 2010 ).
Collagen Scaffolds For the scaffold manufacturing, collagens originated from
marine products are indispensable due to severe infection problems from animal
source; such as bovine spongiform encephalopathy, avian and swine infl uenzas, and
tooth-and-mouth disease in bovine, pig, and buffalo that occur all over the world
(Hayashi et al. 2012 ). Three scaffold-design parameters are accepted as infl uencing
tissue regeneration: (i) modifi cation of scaffold surfaces to enhance cell interaction,
(ii) controlled release of growth factors from scaffolds, and (iii) scaffold mass transport (Hollister 2009 ).
Collagen scaffolds with excellent biocompatibility which were derived from
fresh water fi sh have been reported recently by Pati et al. ( 2012 ):
“The fi sh collagen scaffolds exhibited considerable cell viability and were comparable with that of bovine collagen. SEM and fl uorescence microscopic analysis
revealed signifi cant proliferation rate of cells on the scaffolds, and within 5 days the
cells were fully confl uent. These fi ndings indicated that fi sh collagen scaffolds
derived from fresh water origin were highly biocompatible in nature,” (Pati et al.
2012 ). Marine fi sh collagens are also known as good sources for designing tissue
scaffolds.
8.2 Fish Collagen as a Biomaterial