UNS: Enhancing charge transport in enzymatic bio-electrodes using an iron-sulfur-based synthetic electron-transport-chain

UNS：使用铁硫基合成电子传输链增强酶生物电极中的电荷传输

• 批准号: 1511303
• 负责人: Sandun Fernando
• 金额: $ 30.2万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1511303&HistoricalAwards=false
• 关键词: UNS; Enhancing; charge; transport; enzymatic

Fernando, 1511303Enzymatic biofuel cells work on the same general principles as all fuel cells, they use a catalyst to separate electrons from a parent molecule and force it to go around an electrolyte barrier through a wire to generate an electric current. The enzymatic biofuel cell uses enzymes derived from living cells. The enzymes that allow the fuel cell to operate must be "immobilized" (attached) near the anode and cathode in order to work properly; if not immobilized, the enzymes will diffuse into the cell's fuel and most of the liberated electrons will not reach the electrodes, compromising its effectiveness. The overall effectiveness of all enzyme-based electrochemical devices is dependent on the ability of the molecules that attach enzymes to the electrode to successfully harvest and transport charges from the outer oxidizing point (enzyme active-site) to the inner electrode surface. Redox enzymes are naturally-occurring sensing devices that can act as power plants due to their ability to generate an electron stream in the presence of the enzyme-specific analyte. When these enzymes are wired to electrodes (outside a living cell or ex vivo), their ability to harness these electrons (or electricity) diminishes significantly due to the thermodynamic limitations associated with the coenzymes (that are essential for proper functioning of the enzyme). The common coenzymes, nicotinamide-adenine-dinucleotide (NAD) and Flavin-adinie-dinucleotide (FAD), are resistant to cyclic oxidation and reduction ex vivo; and require special molecules known as electron mediators to help extract electrons from the cofactor to transfer to the final target. Long molecular wires help eliminate the thermodynamic issue but themselves create electron transport (kinetic) issues due to increased resistance. Nature has found a way to circumvent the thermodynamic and kinetic electron transport issues associated with redox enzymes by using an array of unique molecules, the iron-sulfur complexes ([Fe-S]), to wire the enzyme (apoenzyme and coenzyme) complex to the supporting surfaces (like those found in biological electron transport chains). [Fe-S] complexes seem to have a unique combination of properties that facilitate unimpeded electron transport in biological systems.The objective of this project is to evaluate the reaction and electron transport kinetics of enzymatic electrodes of which NAD and FAD based enzyme systems are directly attached using common iron sulfides and select [Fe-S] complexes (mimicking the critical iron-sulfur link(s) in biological electron transport chains). The PI will evaluate the possibility of fabricating a highly effective molecular wire for transporting electrons ex vivo.A major educational objective is to integrate research into education via an undergraduate course and a graduate level course. Research Experience for Academic Change (REACH) is a program in which students who are academically at risk will be paired with academically successful students and provided with research opportunities early in their undergraduate program. The PI plans to evaluate whether their early exposure to practical research helps resuscitate their excitement and confidence concerning their engineering education and degree programs.

费尔南多，1511303酶生物燃料电池的工作原理与所有燃料电池相同，它们使用催化剂将电子从母体分子中分离出来，并迫使其通过电线绕过电解质屏障产生电流。酶生物燃料电池使用来自活细胞的酶。允许燃料电池运行的酶必须“固定”（附着）在阳极和阴极附近，以便正常工作;如果不固定，酶将扩散到电池的燃料中，大多数释放的电子将无法到达电极，从而影响其有效性。所有基于酶的电化学装置的总体有效性取决于将酶附着到电极的分子成功地从外氧化点（酶活性位点）收集和运输电荷到内电极表面的能力。氧化还原酶是天然存在的传感装置，由于其在酶特异性分析物存在下产生电子流的能力，其可以充当发电厂。当这些酶连接到电极（活细胞外或离体）时，由于与辅酶相关的热力学限制（对于酶的正常功能至关重要），它们利用这些电子（或电）的能力显着降低。常见的辅酶，烟酰胺腺嘌呤二核苷酸（NAD）和黄素腺嘌呤二核苷酸（FAD），对体外循环氧化和还原有抗性;并且需要称为电子介体的特殊分子来帮助从辅因子中提取电子以转移到最终靶标。长分子线有助于消除热力学问题，但由于电阻增加，其本身会产生电子传输（动力学）问题。自然界已经找到了一种方法来规避与氧化还原酶相关的热力学和动力学电子传递问题，通过使用一系列独特的分子，铁-硫复合物（[Fe-S]），将酶（脱辅基酶和辅酶）复合物连接到支持表面（如生物电子传递链中发现的那些）。[Fe-S]复合物似乎具有独特的特性组合，可促进生物系统中电子传递的不受阻碍。本项目的目的是评估酶电极的反应和电子传递动力学，其中NAD和FAD基酶系统使用常见的硫化铁直接连接，并选择[Fe-S]复合物（模拟生物电子传递链中的关键铁-硫连接）。PI将评估制造用于传输电子的高效分子导线的可能性。一个主要的教育目标是通过本科课程和研究生课程将研究融入教育。学术变革的研究经验（REACH）是一项计划，在该计划中，学术上有风险的学生将与学术上成功的学生配对，并在本科课程的早期提供研究机会。PI计划评估他们早期接触实际研究是否有助于恢复他们对工程教育和学位课程的兴奋和信心。