Protein-based materials, toward a new level of structural control

Abstract

Through billions of years of evolution nature has created and refined structural proteins for a wide variety of specific purposes. Amino acid sequences and their associated folding patterns combine to create elastic, rigid or tough materials. In many respects, nature's intricately designed products provide challenging examples for materials scientists, but translation of natural structural concepts into bio-inspired materials requires a level of control of macromolecular architecture far higher than that afforded by conventional polymerization processes. An increasingly important approach to this problem has been to use biological systems for production of materials. Through protein engineering, artificial genes can be developed that encode protein-based materials with desired features. Structural elements found in nature, such as b-sheets and a-helices, can be combined with great flexibility, and can be outfitted with functional elements such as cell binding sites or enzymatic domains. The possibility of incorporating non-natural amino acids increases the versatility of protein engineering still

Controlling the crystalline three-dimensional order in bulk materials by single-wall carbon nanotubes

“…As we have recently reported, exTTF is a versatile building block towards driving the construction and stabilization of well-ordered nanostructures at different length scales 45,46 . The presence of short peptides enables the organization of chiral b-sheets as secondary structures 47,48 , which ensures the efficient stabilization of a supramolecular order onto SWCNTs. In addition, such organization allows the delocalization of positive charges through stacks of exTTFs.…”

Growth factor delivery for oral and periodontal tissue engineering

“…Extracellular matrix-derived macromolecules such as collagen have been used for many years in biomaterial application [53], and it is now possible to create artificial analogues of extracellular matrix proteins using recombinant DNA technology [54]. Collagen is degraded by cells within regenerating tissue as it develops, and biodegradable synthetic polymers such as poly(lactide-co-glycolide) are hydrolysed into natural metabolites, lactic acid and glycolic acid by the action of water at regenerated sites.…”

Peptide-based biopolymers in biomedicine and biotechnology

“…The coiled coil domain is based on a heptad repeat unit abcdefg, where a and d are typically hydrophobic amino acids (leucine), and e and g are charged (glutamic acid) [179]. Helical stability is maintained by electrostatic interactions between e and g [180]. Coiled coil motifs intended for drug delivery utilize the reversible hydrophobic association of α-helices within the core as well as the electrostatic interaction from the outer charged residues.…”

“…Biological materials such as elastin-based polypeptides, collagens derived from extracellular matrices, fibrins, and spider silk proteins [59,62,153,[183][184][185][186][187] are useful for tissue engineering because they have good chemical compatibility in aqueous solutions, good in vivo biocompatibility, a controllable degradation rate in vivo, the ability to break down into natural amino acids that can be metabolized by the body, and minimal cytotoxicity, immune response, and inflammation [174,[188][189][190][191][192][193][194]. In addition, biopolymers can be easily functionalized to enhance their interactions with cells and provide an optimal platform for cellular activities and tissue functions.…”