DNA enabled biobattery seeking to address the limitations of portable power supply
Abstract
Enzymatic biofuel cells are a type of fuel cell that utilizes enzymes as the electrocatalysts to catalyze the oxidation of fuel and/or the reduction of oxygen or peroxide to convert chemical energy into electricity. These reactions can convert complex fuels, e.g. alcohols, carbohydrates, fatty acids, etc. into energy. The benefit of being able to generate electricity from these fuels is that they are abundant, renewable and inexpensive, and they also have very high energy densities, e.g. lactate = 3041 Wh/L. A biobattery is a device that contains both the enzymatic pathways to oxidize a fuel, such as in an enzymatic biofuel cell, as well as a store of the fuel itself. Significant advancements have been made in biobatteries and biofuel cells from when they were first proposed in 1960 to today where the best published systems are realizing 1000wh/L densities. Excitement around these devices comes from their relative potential energy density compared with current state of the art lithium ion batters (e.g. those in smart phones) which have a density of 300-400Wh/L. Further improvements in efficiency are available through the optimization of various battery elements, but enzyme cascade design/evolution for further oxidation of fuels, as well as enzyme immobilization/stability are two major variables that have the potential to improve biobattery efficiency. Immobilizing enzymes on the electrode surface while retaining their activity and allowing good electrical connection to the electrode is critical for the development of biobatteries and biofuel cells. Various strategies have been investigated for enzyme immobilization, ranging from physical adsorption to covalent binding to the electrode and encapsulation or entrapment of enzymes in polymers. Enzyme immobilization within hydrogels is probably the most widely used strategy, as it keeps enzymes from leaching off the electrode, while still allowing free diffusion of small molecules such as substrates, products, and enzyme cofactors. The hydrogel polymer can also be functionalized and modified with redox molecules to mediate electron transfer between enzyme active site and the electrode. DNA hydrogels have been investigated due to their numerous proposed benefits; they are formed under physiological conditions so allow encapsulation in situ. The unique, double helical structure and negatively charged backbone of DNA offers a potential immobilization strategy for enzymes, organocatalysts, and mediators, resulting in a dense, regular matrix of enzymatic cascade reagents. DNA has received limited attention, in part due to the cost/scale-quality trade off issues associated with supply.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 30, 2019
- Source ID
- N629091912125
Entities
People
- Sarah Milsom
Organizations
- Office of Naval Research
- United States Navy