Biomaterials to Promote Tissue Regeneration

Part 3 of the Handbook, the domain of materials engineering, contains six chapters. Three deal with classes of biomaterials—biopolymers, composite biomaterials, and bioceramics—and three deal with using biomaterials, in cardiovascular and orthopedic applications, and to promote tissue regeneration. 

Electrical Stimuli. Electrically active materials have also been used to encourage tissue growth. The use of piezoelectric materials made of vinyUdene fluoride-trifluoroethylene copolymer [P(VDF-TrFE)] enhanced peripheral nerve regeneration in vivo (Fine et al., 1991), and when PC12 cells were cultured on oxidized polypyrrole, the application of an electrical stimulus resulted in enhanced neurite extension (Schmidt et al., 1997), as shown in Fig. 16.3. Implant vascularization was enhanced when bilayer films of polypyrrole-hyaluronic acid and polypyrrole-poly(styrenesulfonate) were implanted subcutaneously (Collier et al., 2000). These types of electrical stimuli can be used in conjunction with a biomaterial to promote tissue regrowth. 

These biomaterials should guide cells, promote their local proliferation, and improve the environmental to permit tissue regeneration in the lesion site aimed at replacement of the natural tissue. The scaffolds can be used for regenerating the spinal cord, peripheral nerves, skin, cartilage, vessels, bone, as well as other tissue. 

Composites made with carbon nanostructures have demonstrated their high performance as biomaterials, basically applied in the field of tissue regeneration with excellent results. For example, P.R. Supronowicz et al. demonstrated that nanocomposites fabricated with polylactic acid and CNTs can be used to expose cells to electrical stimulation, thus promoting osteoblast functions that are responsible for the chemical composition of the organic and inorganic phases of bone [277]. MacDonald et al. prepared composites containing a collagen matrix CNTs and found that CNTs do not affect the cell viability or cell proliferation [278]. 

In addition to promoting periodontal tissue regeneration, a study published in 2014 has shown that EMD promoted in vitro biomimetic mineralization and facilitated enamel prism-like tissue formation on demineralized human enamel. Thus, using EMD in biomimetic mineralization may serve as a biomaterial for enamel repair (Cao et al., 2014). So far, several brands based on EMD have been marketed the first to be commercially available of those is Emdogain. 

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