Epitaxial Growth of Structural Proteins into Hierarchical Mesostructured Materials
Abstract
There is a compelling need to establish new fabrication techniques that seamlessly blend top-down and bottom-up approaches to simultaneously operate at the nano-, micro-, and macro-scale, ultimately allowing for the fabrication of hierarchical mesostructured materials. This manufacturing approach is very similar to biofabrication, where living organism precisely organize structural proteins across several scales (from nano to macro) by combining bottom-up and top-down fabrication principles. However, a poor understanding of the coordination of forces and fields involved in proteins assembly and the technological gap between top-down and bottom-up fabrication methods have limited the reproduction of the complex hierarchical mesostructures found in the biotic world and the engineering of new ones. Several fabrication techniques have been successfully developed to engineer well-ordered nanoporous materials. These methodologies involve complex time- and energy-consuming steps, can generally be controlled only on relatively small dimensions (mm2 to few cm2) and require a meticulous regulation of the assembly environment. Thus, a simple, fast, energy efficient and robust processes to fabricate at scale (tens of cm2 to meters2) hierarchical mesostructured materials has still to be developed. TECHNICAL APPROACHES. The aim of this program is to address this need by focusing on a set of interrelated scientific issues that underpins the assembly of structural proteins and their pick and place fabrication to enable the formation of hierarchical mesostructured materials. We hypothesize that polypeptides of defined amino acidic sequence and structures can act as seeds to template folding and assembly of structural proteins and to enable their homo- or hetero-epitaxial growth. The obtained mesostructured materials possess finely-controlled physical and biochemical properties and can be used in bulk materials to impart complex mesostructures and hierarchical features by modulating their sacrificial decomposition and spatial localization. We will test our central hypothesis by pursuing the following tasks: Task 1: Homoepitaxial growth of silk fibroin materials; Task 2: Heteroepitaxial growth of silk fibroin materials; Task 3: Fabrication of hierarchical, mesostructured silk materials. ANTICIPATED OUTCOME. We anticipate the following program outcomes: (i) Mechanistic understanding of structural protein assembly in hierarchically-organized architectures by the definition of universal rules that regulate the formation of stable configurations based on epitaxial growth; (ii) A novel biofabrication strategy that allows to engineer mesoparticles of complex geometry and defined physical properties; (iii) Rational inclusion of functional amino acid sequences that impart orthogonal functions (adhesiveness, biomineralization) to hierarchically-organized materials; (iv) The validation of an unprecedented fabrication strategy that blend top-down and bottom-up approaches. IMPACT ON DOD CAPABILITIES. The completion of research tasks 1-3 will be ancillary for the definition of unprecedented fabrication rules to engineer hierarchical mesostructured materials with foreseen applications in: 1) shock-absorbing materials, 2) underwater adhesive, 3) self-healing in seawater and 4) fractionated material, which could impact a wide range of applications of interest to the ONR. Reduction of friction, augmented mechanical properties, under-water adhesives, and material controlled-decomposition could improve the performance of ships and vessels as well as open new doors to close-in ISR systems for situation awareness and programmed-degradation upon distribution in the environment. APPROVED FOR PUBLIC RELEASE.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812258
Entities
People
- Benedetto Marelli
Organizations
- Massachusetts Institute of Technology
- Office of Naval Research
- United States Navy