Polymer-based tissue engineering

The aim of this chapter is to give a brief selective overview of typical biomedical areas where cationic polymers can be employed. The use of cationic polymers in tissue engineering is a high priority topic in this chapter and several aspects on this phenomenon are given related to this is the potential of cationic hydrogels for medical and pharmaceutical applications. The importance of cationic polymers and copolymers as non-viral vectors in gene therapy is described, as well as how micelles and vesicles based on cationic polypeptides can form nanostructures by self-assembly. The potential of cationic polymers for drug delivery applications is also elucidated. 

Although the polymer coating-based TRCS is inexpensive and convenient method as described above, there are some issues related to contamination by (1) the desorption of the coated polymer during cell culture and/or by lowering temperature as mentioned above and (2) difficulty in fabricating cell sheet without a defect. The issues may be problems in cell sheet-based tissue engineering. 

Guilbert, S. (2002) Protein-based Bio-Plastics formulation, thermoplastic processing and main applications International Congress Trade Show The Industrial Applications of Bioplastics, 3rd, 4th and 5th February Gunatillake P.A. and Adhikari R. (2003) Biodegradable synthetic polymers for tissue engineering , European Cells and Materials, 5, 1-16. 

Pego AP, Siebum SB, Luyn MJAV, et al. Preparation of degradable porous structures based on 1,3-trimethylene carbonate and D,L-lactide(co)polymers for heart tissue engineering. Tissue Eng, 2003, 9, 981 994. 

PGA was one of the very first degradable polymers ever investigated for biomedical use. PGA found favor as a degradable suture, and has been actively used since 1970 [45 -7]. Because PGA is poorly soluble in many common solvents, limited research has been conducted with PGA-based drug delivery devices. Instead, most recent research has focused on short-term tissue engineering scaffolds. PGA is often fabricated into a mesh network and has been used as a scaffold for bone [48-51], cartilage [52-54], tendon [55, 56], and tooth [57]. 

The polymer/SWCNT composites can be used as Scaffolds in tissue engineering. The donor-acceptor interactions can be used to assemble thin polymer/SWCNT films stepwise. This method also can be expended to more thermally and oxidatively stable polymer systems. For example, the P4VP/SWCNT films can be used as scaffolds for the synthesis of novel hybrid structures (Correa-Duaite et al., 2004). The polyethyl-enimine (PEI)-SWCNTs composites were used as a substrate for cultured neurons, and promoted neurite outgrowth and branching (Rouse et al., 2004). Correa-Duarte et al. (2004 Landi et al., 2005) reported that 3D-MWCNT-based networks are ideal candidates for scaffolds/matrices in tissue engineering. 

Silva et al. (2006) studied starch-based microparticles as a novel strategy for tissue engineering applications. They developed starch-based microparticles, and evaluated them for bioactivity, cytotoxicity, ability to serve as substrates for cell adhesion, as well as their potential to be used as delivery systems either for anti-inflammatory agents or growth factors. Two starch-based materials were used for the development of starch-based particulate systems (1) a blend of starch and polylactic acid (SPLA) (50 50 w/w) and (2) a chemically modifled potato starch, Paselli II (Pa). Both materials enabled the synthesis of particulate systems, both polymer and composite (with BG 45S5). A simple solvent extraction method was employed for the synthesis of SPLA and SPLA/BG microparticles, while for Pa and Pa/BG... 

Torres et al. (2006) reported a novel microwave processing technique to produce biodegradable scaffolds for tissue engineering from different types of starch-based polymers. Potato, sweet potato, com starch, and non-isolated amaranth and quinoa starch were used along with water and glycerol as plasticizers to produce porous stmctures. Figure 16.1 shows the manufacturing procedure of microwaved starch scaffolds. 

Zang et al. developed a peptide-based polyurethane scaffold for tissue engineering. LDI was reacted with glycerol and upon reaction with water produced a porous sponge due to liberation of CO2. Initial cell growth studies with rabbit bone marrow stromal cells showed that the polymer supported cell growth. 

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