Synthesis, Characterizations, and Medical Applications of Bioelastic Materials

Abstract

Bioelastic materials are elastomeric polypeptides composed of repeating sequences. They are a relatively new class of polymers that may also be called elastic protein-based polymers, having their origins in repeating sequences found in the mammalian elastic protein, elastin. The most striking and longest sequence between cross-links in pig and cow is the polypentapeptide-(PPP), poly(VPGVG) or (Val¹-Pro²-Gly³-Val⁴-Gly⁵)n, where n is 11 (Sandberg et al., 1985; Yeh et al, 1987). Another repeat first found in porcine elastin is a polytetrapeptide-(PTP), poly(VPGG) or (Val¹-Pro²-Gly³-Gly⁴)n, but this repeat has not been found to occur with n greater than 2 without substitution (Sandberg et al., 1981). The next most common recurring sequence in mammalian elastin is a polyhexapeptide-(PHP), poly(APGVGV) or (Ala¹-Pro²-Gly³-Val⁴-Gly⁵-Val⁶)n where, with but a couple of isomorphous hydrophobic residue replacements such as Val by He or Leu, n is 8 in man (Indik et al., 1987). The monomers, oligomers, and high polymers of these repeats have been synthesized and conformationally characterized (Urry and Long, 1976). The high polymers of these repeating sequences have been cross-linked into sheets, rods, and tubes, and the PPP and PTP have been found to be elastomeric with the former being capable of an elastic modulus similar to that of the natural elastic fiber (Urry et al., 1976, 1981, 1982).