Bio-functionalization of Titanium (Ti) by Amine Groups for Advanced Materials Development
Project Description
Develop a multifunctional biomimetic material that exhibits damage tolerant and self-healing adhesive properties for space and terrestrial applications that is activated by a simple sugar solution. Biomimicry and biomimetic materials are enabling technologies that support journey to Mars exploration for structural applications In this case, collagen molecules are covalently bonded to a hard inert surface like titanium (Ti), this will allow for adhesion between two Ti structures, similar to how ligaments attach to bones. Self-assembly of ~100 um long collagen fibrils initiated by the covalently bonded molecules will form a microscopic brush like surface structure. When two such surfaces are brought together, the brushes will interdigitate. Subsequent exposure to a simple sugar solution (i.e. glucose in water) causes covalently crosslinking between the brushes. This new material system would rely on the robust properties of collagen fibrils to create a bio-inspired adhesive that is more resilient than cyanoacrylates, more amenable to in-situ repair, and can bond rough surfaces without the need for toxic or hazardous chemicals or solutions. In addition, the adhesive can be released using an enzyme that functions in water near neutral pH. Eliminating complex permanent adhesives will benefit robotic construction allowing parts to be repositioned if necessary in the event of misalignment. Additionally, in-situ resource utilization (ISRU) can be leveraged to provide the liquid water required for the solution, resulting in a significant reduction in launch mass. This would be accomplished by employing a multi-disciplinary process. In this low TRL proof of concept proposal, we initially create Ti surfaces with collagen fibrils oriented with their axis of symmetry perpendicular to the Ti surface. Two fibril containing surfaces will be placed into contact and the interface saturated with a sugar solution. Mechanical properties of the interface will be evaluated including tensile and shear strength and stiffness. The joined parts will then be separated and rejoined and mechanical properties re-\xad-evaluated. The goal is to demonstrate the ability to fuse two Ti substrates together via a biomimetic interface (collagen fibrils) and to evaluate robustness of the interface.
More »Anticipated Benefits
This proposal suggests a new approach to habitat and space component assembly based on a biomimetic approach that is accomplished by nano-modification of a metallic surface. Assembled structures would have high durability along with self-healing capabilities. The assembly process is predicated on the robust nature of collagen fibrils and a simple sugar solution as the prime activation ingredient. Since the glue is a sugar solution, the solution lends itself to on site fabrication by ISRU. Only the dry sugar would need to be included in the launch mass. This technique potentially allows for parts to be repositioned or repaired in the event of misalignment or damage. This approach is amenable to remote or robotic assembly. Current epoxy or cyanoacrylate methods are permanent, typically not easily repairable and result in a significant increase in launch mass. In addition, they tend to have toxic organic fumes associated with their use. Also, cyanoacrylates tend to degrade under long term exposure to water. The proposed system is biologically designed to work well under long term aqueous exposure. Future missions that are either orbiting satellites or rovers could potentially benefit from this technology. Treated surfaces are potentially either self-healing or repairable by application of additional collagen molecule and/or sugar solutions. Beyond the adhesion aspect of this proposal, this technique is of interest to the medical profession as possible method of treating implants. Loss of fixation is, statistically, the number one failure mode of total hip and knee implants. The biomimetic nature of the proposed adhesion has strong potential to solve this problem.
More »Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
Glenn Research Center
(GRC)
|
Lead Organization | NASA Center | Cleveland, Ohio |
| Case Western Reserve University | Supporting Organization | Academia | Cleveland, Ohio |
Primary U.S. Work Locations
-
Ohio
