Nano-Hydroxyapatite/Collagen/PLLA Reinforced by Chitin Fibers
In addition to using chitin as the scaffold matrix, it is also possible to use chitin fibers for reinforcing other biocompatible matrix materials. One such example are nano-hydroxyapatite/collagen (nHAC)/Poly-l-lactic acid (PLLA) scaffolds. PLLA is promising for biomedical applications as it is biocompatible, biodegradable and non-toxic. However, it has poor mechanical properties, it is hydrophobic and the products it is decomposed to during degradation by hydrolization are acidic. The existence of such acidic products increases the hydrolization rate and therefore degradation occurs faster. PLLA is therefore commonly combined with other materials, such as chitin fibers since they are alkalescent and can neutralize the acidity, decreasing hence the degradation rate. Furthermore, such fibers increase its mechanical strength. In this section the properties for porous nHAC/PLLA materials reinforced chitin fibers are described, as presented in . To increase the strength of the interfacial bonding the chitin fibers were first linked with PLLA and then added to the nHAC/PLLA solution. The chitin fibers had a diameter of 12.5 |rm and tensile strength of 550 MPa. To examine the effect of fiber content samples were prepared at separate chitin volume % of 10, 20, 30, 40 and 50.
Fig. 4.6 Scanning electron micrograph of: (a) the samples in which chitin was not Linked with PLLA; (b) the samples in which chitin was linked with PLLA (Reproduced with permission from Ref. )