Tissue Transplantation Research Paper

Immense progress has been made in recent years in organ transplantation, surgical re-establishment and the use of artificial materials to treat the loss or defects of an organ or tissue. However, the drawbacks associated with these types of treatments have led to the consideration of tissue engineering approach using cells and materials based three dimensional scaffolds. Polymers, ceramics and metals have been extensively used as materials in the construction of three-dimensional scaffolds for tissue regeneration [1-10]. These scaffolds should provide the necessary support as artificial extracellular matrices, allowing cells to proliferate and maintain their differentiated functions without any inflammation and serve as a template to guide

It is soluble in hexafluroisopropanol, hexafluroacetone and chloroalcohols. Whereas, chitosan is deacetylated product of chitin, is soluble in acetic acid and formic acid. The nitrogen content of chitin is mostly acetylated group, whereas, nitrogen in chitosan is mostly in the form of primary aliphatic amino group. Preparative procedure of chitin and chitosan are shown in Fig, 2 (a) Chitin and chitosan are excellent functional materials for biomedical applications because of their high biocompatibility, biodegradability, antibacterial activity, non-antigenicity and high adsorption properties that makes them appropriate for tissue engineering (Fig. 2 (b))[15-18]. Chitin and chitosan have also been shown to support cell attachment and proliferation well due to their hydrophilic nature.

Fig. 2

The main advantage of chitin and chitosan is the ease with which they can be processed into different forms like beads, gels, microparticles, nanoparticles, nanofibers, scaffolds etc. (Fig. 3). Other advantages of chitin and chitosan scaffolds for tissue engineering include the formation of highly porous scaffolds with interconnected pores, osteoconductivity and ability to enhance bone formation both in vitro and in vivo.

Fig.

In addition, the mineralization effect of chitosan-nHAp increases in the stimulated body fluid solution as compared to chitosan scaffold only. Similar response was seen by the addition of nHAp in membranes [75, 90, 100, 105,107,108] . Liu et al have incorporated nHAp in chitosan nanofibers by co-preipitation method. This scaffold tend to show compositional and structural feature similarity to natural bone ECM and thus showed enhanced BMSCs adhesion, spreading and cell viability and proliferation. Furthermore, this scaffold induced osteogenic differentiation of BMSC both in vitro and in vivo by activating integrin and BMP/Smad signaling pathway. Calvarial defect healing was also significantly enhanced in the nanocomposite group [90]. Although chitosan-nHAp composite biomaterials have proven their worth as potential scaffold systems, ternary composite systems have also been widely prepared employing chitosan/nanoHAp with β-glycerophosphate [44,45,46], polyamide-6,6 [42], collagen [103], starch [104], gelatin [104,105,113], zinc oxide [56], poly(galacturonic acid) [94], poly(lactide-co-glycolide) [99], cellulose [100], collagen gels [49], hyaluronic acid [83], Cu-Zn alloy nanoparticles (nCu-Zn) [74], sodium carboxymethyl cellulose [51, 57, 58,