Living organisms are green chemist masters, producing multi-functional materials under benign environmental conditions, with a limited amount of building blocks. Thus, they constitute important biomimetic model systems for eco-friendly and multi-scale processing of materials.
Proteins constitute either the structural components of biological materials or the templates that control the growth and self-assembly of inorganic components into complex hierarchical biocomposites.
In this talk, our pioneer efforts in establishing Next-Generation sequencing (RNA-Seq) in the context of biomimetic materials engineering will be described. I will specifically illustrate our efforts in deploying this platform towards the intriguing squid Sucker Ring Teeth (SRT), which are remarkable protein-based materials that can compete with the best structural synthetic polymers in terms of mechanical performance. Despite these unusual properties, inter-chain chemical crosslinking is absent and the teeth are fully stabilized by a network of hydrogen bonds. We have shown that SRT are entirely made of modular suckerin proteins, which assemble into a supramolecular network reinforced by nano-confined β-sheets. Because of their supra-molecular assembly, SRTs exhibit thermoplastic properties (an unusual feature for a protein-based material), which can be exploited to re-process and mold the proteins into complex shapes by simple lithographic techniques and make SRT a promising material as bio-ink for 3D bioprinting.
We have also established recombinant expression systems that allow us to readily express full-length suckerins in large quantities. The specific molecular architecture of suckerins can be exploited to prepare biomaterials spanning 7-orders of magnitude of elasticity, from soft gels matching the elasticity of liver to stiff films with a Youngs modulus approaching that of bone. The ease of processability and redox activity of suckerins can also be used to induce the growth of metallic nanoparticles without reducing agents, including from redox-active nano-structured solid substrates.
I will also describe our recent efforts in engineering suckerins for nanomedicine applications. Suckerins can be prepared into nanoparticles with a controlled particle size in the 100-200 nm size range, and we have successfully used these nanoparticles for efficient drug delivery and gene transfection in vitro and in vivo. Notably, suckerin nanoparticles are able to encapsulate hydrophobic drugs for pH-dependent release in vitro, and can also effectively inhibit tumor growth in vivo. Suckerins can also complex and stabilize plasmid DNA, with the complexes stabilized by hydrophobic interactions of the β-sheet domains as opposed to electrostatic interactions commonly achieved with cationic polymers, thus lowering cytotoxicity traditionally associated with such polymers.
Prof. Miserez did his PhD in MSE at EPFL, a post-doc at UC Santa Barbara, and joined NTU in 2009.