Application of Chitosan-Based Biomaterials in Tissue Engineering - Chitosan Based Hydrogels: Functions and Applications - page 407

250

200 nm

200

103

150

83

60

100

50

0 0

1 2 3 4

Solution concentration (wt.-%)

5 6 7 8 9

Figure 9.5
Relationship between the concentrations of the prespun chitosan/TFA solutions and the mean diameters of the
electrospun chitosan fibers. Numbers with arrows indicate the mean fiber diameter in the optimized spinning
condition, giving the relatively homogeneous fiber networks. (From Ohkawa, K. et al. 2006. Biomacromolecules
7:3291-3294. With permission.)

9.2.3 Chitosan-based Microsphere Scaffolds

Recently, microspheres have also been assessed as scaffolds for tissue engineering, and
new strategies, such as sintering and fusion methods, have been investigated to obtain
suitable scaffolds that mimic the tissue environment for cells. Most of the concepts based
on the use of such scaffolds require the implantation kind of the hybrid constructs through
a surgical procedure. The process of scaffold fabrication consisted of the following steps.
(1) Preparation of chitosan-based microspheres: polymer dissolving, spheres production
by extrusion of the solution to the precipitating bath, pH neutralization, scaffold forma-
tion, chitosan cross-linking, rinsing, and drying. (2) Microsphere scaffold formation:

TAble 9.1
Electrospun Chitosan Composites Nanofibers

Average Fiber
Diameter (nm) Composites Solvent References

Chitosan/collagen HFP/TFA 415-810 (−) [21,22]

Chitosan/gelatin TFA/DCM 100-220 [23]

Chitosan/agarose TFA/DCM 140-1500 (+) [24]

Chitosan/PEO aq. AA 80-180 [25]

Chitosan/PLA TFA [26]

40-1200 (−)

Chitosan/PCL Formic acid/acetone 112.9-139.6 [27]

Chitosan/PVA aq. AA 20-100 [28]

Chitosan/PLGA Chloroform/DMF 272 [29]

Note: (+), diameter of composites increases with increasing chitosan content; (−), diameter
of composites decreases with increasing chitosan content.
HFP, 1,1,1,3,3,3-hexafluoroisopropanol; TFA, trifluoroacetic acid; DMF, N,N-dimethyl-
formamide; aq. AA, aqueous acetic acid solution; DCM, dichloromethane; PVA, poly(vinyl
alcohol); PEO, poly(ethylene oxide); PLA, poly(lactic acid); PLGA, poly(lactide-co-glycolide);
PCL, polycaprolactone.