Biomimetic Polysaccharides and Derivatives for Cartilage Tissue Regeneration - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 15

penetrating the scaffolds pores [103]. It was observed that the fi ber mesh
network for support of cell growth and development presents good inter-
connectivity. The fi ber network structure and an extensive porous area
(approximately 75% as estimated by m CT) is an advantage with regard to
the cells penetration into the bulk of the scaffold while at the same time
enhancing nutrient diffusion and removal of metabolic wastes. Sa-Lima
et al. [104] evaluated the starch-CS hydrogels induced chondrocytic dif-
ferentiation and cartilage matrix accumulation and also the infl uence of
starch in the chondrogenesis of encapsulated adipose derived stromal
(ADSC) cells. The ADSC were found to be homogeneously encapsulated,
viable, proliferating and maintaining the expression of typical chondro-
genic markers genes, and depositing cartilage ECM molecules.
1.4.5 Cellulose-basedMaterials
Cellulose is the most abundant natural and renewable resource polysac-
charide, available worldwide. This polymer exists in lignocellulosic mate-
rial in forest and plants. Other sources are algae, bacteria biosynthesis,
and chemosynthesis [105]. Among all celluloses, the bacterial cellulose
(BC) has unique properties including high purity, a nanofi brous struc-
ture, high crystallinity, high tensile strength and good biocompatibility
[106-110]. Thus, many researchers have focused on BC-based materials
for various biomedical applications, including blood vessel engineering
[111] and wound healing [112], which exhibited good in vivo biocompati-
bility after 12 weeks of subcutaneous implantation in rats, and were found
to be well integrated into the host tissue without any chronic infl amma-
tory responses [113]. Svensson et al. [114] have demonstrated that BC is a
potential scaffolding material for cartilage regeneration, and investigated
the native and chemically modifi ed BC (by phosphorylation and sufation)
materials using bovine chondrocytes. The results indicate that unmodi-
fi ed BC supports chondrocyte proliferation at levels of approximately 50%
of the collagen type II substrate, while providing signifi cant advantages
in order to improve mechanical properties. Compared to tissue culture
plastic and calcium alginate, unmodifi ed BC showed signifi cantly higher
levels of chondrocyte growth. Even though chemically modifi ed BC was
able to mimic the glucosaminoglycans of native cartilage it did not signifi -
cantly enhance chondrocyte growth. However, the porosity of the mate-
rial was found to affect the chondrocyte viability.
For cartilage tissue engineering application, the delivery of cells by an
injectable hydrogel scaffold as a noninvasive surgery procedure is a prom-
ising approach. In this application the desired cell-based construct must be
retained at the repair site after being injected [115]. To achieve this require-
ment, researchers have focused on the development of a hydrophilic
polymer able to exhibit self-reticulation properties [116]. An interesting