Advancing Novel Rebreather Chemistry for Technology Transitioning
Abstract
Project Abstract-Approved for Public ReleaseCurrent diving operations benefit from the use of a rebreather (i) by extending the brea,thing endurance of the diver and (ii) for converting operations by eliminating the bubbles produced from exhaled gas from the diver., Modern-day rebreathers rely on reacting base, calcium hydroxide, with carbon dioxide, CO2, to precipitate calcium carbonate within,the rebreather. To enable more facile sea-land transitions, a new chemistry is being developed that allows CO2 to be removed from an, exhalant stream ?on the fly?, thus ultimately allowing for a rebreather to be eliminated. A reaction that is readily adaptable to c,urrent diving operations is to scrub CO2 from an exhalant stream to produce carbonic acid, H2CO3, which is soluble in seawater, and,may simply be dissolved as a salt at the pH of seawater. Two types of catalysts have been developed for this chemistry: a carbonic a,nhydrase (CA) enzyme and molecular catalysts that are carbonic anhydrase biomimics (CA-Bm). This proposal seeks to modify these cata,lysts so that they may be immobilized on solid supports. Surface lysines and cysteines on CA will be targeted for site-specific atta,chment of CA to the support through amidyl and sulfhydryl chemistries, respectively. Fluorescent assays will be contracted to allow,quantification of CA loading on supports. For CA-Bm catalysts, ligands will be functionalized to allow their coupling to carbon, pol,ymer and oxide supports and streptavidin beads. Each support has an associated immobilization chemistry. Long-term stability and cyc,lability assays will be performed. Experiments will be performed in seawater and under low CO2 concentrations with different support,/anchor combinations to determine which materials exhibit optimum performance under conditions relevant for rebreather applications., The materials developed from this program will be made available to those companies/research efforts interested in constructing an,engineered device. The elimination of a rebreather backpack offers new capabilities for multi-domain operations as the backpack woul,d not need to be managed during sea and land transitions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 08, 2022
- Source ID
- N000142212758
Entities
People
- Daniel G. Nocera
Organizations
- Office of Naval Research
- President and Fellows of Harvard College
- United States Navy