Abstract：
Nanowires have substantial potential as the sensor component in electronic sensing devices. However, surface functionalization of traditional nanowire and nanotube materials with short peptides that increase sensor selectivity and sensitivity requires complex chemistries with toxic reagents. In contrast, microorganisms can assemble pilin monomers into protein nanowires with intrinsic conductivity from renewable feedstocks, yielding an electronic material that is robust and stable in applications, but also biodegradable. Here we report that the sensitivity and selectivity of protein nanowire-based sensors can be modified with a simple plug and play genetic approach in which a short peptide sequence, designed to bind the analyte of interest, is incorporated into the pilin protein that is microbially assembled into nanowires. We employed a scalable Escherichia coli chassis to fabricate protein nanowires that displayed either a peptide previously demonstrated to effectively bind ammonia, or a peptide known to bind acetic acid. Sensors comprised of thin films of the nanowires amended with the ammonia-specific peptide had a ca. 100-fold greater response to ammonia than sensors made with unmodified protein nanowires. Protein nanowires with the peptide that binds acetic acid yielded a 4-fold higher response than nanowires without the peptide. The protein nanowire-based sensors had greater responses than previously reported sensors fabricated with other nanomaterials. The results demonstrate that protein nanowires with enhanced sensor response for analytes of interest can be fabricated with a flexible genetic strategy that sustainably eliminates the energy, environmental, and health concerns associated with other common nanomaterials.
摘要：
纳米线作为电子感测装置中的传感器组件具有相当大的潜力。然而,用增加传感器选择性和灵敏度的短肽对传统纳米线和纳米管材料进行表面官能化需要使用有毒试剂进行复杂的化学处理。相比之下,微生物可以从可再生原料中将菌毛单体组装成具有固有导电性的蛋白质纳米线，产生一种在应用中坚固稳定的电子材料，但也可生物降解。在这里，我们报告了基于蛋白质纳米线的传感器的灵敏度和选择性可以通过简单的即插即用遗传方法进行修改，其中短肽序列，旨在结合感兴趣的分析物，结合到微生物组装成纳米线的菌毛蛋白中。我们采用了可扩展的大肠杆菌底盘来制造蛋白质纳米线，该纳米线展示了先前证明可以有效结合氨的肽，或已知与乙酸结合的肽。由用氨特异性肽修饰的纳米线薄膜组成的传感器具有约对氨的响应比使用未修饰的蛋白质纳米线制成的传感器高100倍。具有结合乙酸的肽的蛋白质纳米线产生比没有肽的纳米线高4倍的响应。基于蛋白质纳米线的传感器比以前报道的用其他纳米材料制造的传感器具有更大的响应。结果表明，对于感兴趣的分析物，具有增强的传感器响应的蛋白质纳米线可以通过可持续消除能量的灵活遗传策略来制造，环境,以及与其他常见纳米材料相关的健康问题。
