Wiring enzymes to electrodes using biomimetic membranes
Open Access
- Author:
- Saboe, Patrick Owen
- Graduate Program:
- Chemical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 27, 2016
- Committee Members:
- Manish Kumar, Dissertation Advisor/Co-Advisor
Manish Kumar, Committee Chair/Co-Chair
Andrew Zydney, Committee Member
Phillip E Savage, Committee Member
John H Golbeck, Outside Member - Keywords:
- Bio-inspired membranes for energy and the environment
- Abstract:
- Biomimetic membranes incorporate elements or paradigms inspired by biological membranes or incorporate biological elements themselves. Interest in these membranes has grown rapidly in recent years, from being a science-based inquiry to larger commercialization efforts. My motivation stems from the fact that there are many effective biological elements and mechanisms that provide elegant solutions to current engineering challenges. The ultimate goal of my dissertation research was to design a biomimetic membrane that seamlessly integrates biological and synthetic electronic circuits. The first chapter of the dissertation is a comprehensive review that provides a guide to understand, design and improve electrode interfaces for redox enzyme electron transfer processes in devices. I aimed to understand wiring techniques by finding a biological equivalent system to each engineering system introduced. The biological examples provide the framework to understand electron transfer mechanisms, kinetics, and scalability of redox enzyme bioelectronics for environmental, biomedical and energy applications. The design of state-of-the-art devices is put in context of biological architectures and processes. The biocompatibility of devices is clearly defined in respect to biological environments. I seek to improve electrode interfaces by presenting and innovating effective biological systems and biomimetic approach suggestions to engineering challenges. The research chapters that follow provide unique solutions to existing problems of wiring enzymes to electrodes (chapters 2 and 3) and more generally to the field of biomimetic membranes (chapter 4). I introduce an innovative electrode interface for the utilization of redox proteins, specifically photosynthetic membrane proteins. Electrodes were modified with lipids, biomimetic block copolymers, and conjugated oligoelectrolytes (COEs). The optimized design interface essentially consists of a block copolymer bilayer on electrodes with intercalated COEs. Stability requirements, for both the interface and interacting proteins, were satisfied by the use of hydrated, crosslinkable, lipid-like block copolymers (BCPs) as the matrix of electrode protein interfaces. I have shown that these block copolymers become mobile in the presence of detergent molecules for application of incorporation of membrane proteins. I used this finding optimize integration of photosynthetic membrane proteins into block copolymer membranes, which stabilizes the protein function. This design generated a maximum photocurrent of 35.0 ± 3.5 µA/cm2 upon illumination of the assembled devices with photosynthetically active radiation (PAR), among the highest and most stable photocurrents reported so far for such systems. The work in this dissertation is applicable to many fields including environmental and medical biosensors, enzymatic fuel cells and bioelectrosynthesis.