Organosilanes are commonly utilized to attach bioreceptors to oxide surfaces. The deposition of such silane layers is especially challenging in nanoscale or nanoconfined devices, such as in nanopipettes, since rinsing off loosely bound silanes may not be possible due to geometric constrictions and because the thickness of multilayered silanes can cover or block nanoscale features. Furthermore, in electrochemical devices, the silane layers experience additional perturbations, such as electric migration and electroosmotic force. Despite its importance, there appears to be no consensus in the current literature on the optimal methodology for nanopipette silanization, with significant variations in reported conditions. Herein, we systematically investigate the reproducibility and stability of liquid- and vapor-phase deposited silane layers inside nanopipettes. Electrochemical monitoring of the changing internal silanized surface reveals that vapor-deposited APTES generates surface modifications with the highest reproducibility, while vapor-deposited APTMS generates surface modifications of the highest stability over a 24-hour time period. Practical issues of silanizing nanoconfined systems are highlighted, and the importance of carefully chosen silanization conditions to yield stable and reproducible monolayers is emphasized as an underappreciated aspect in the development of novel nanoscale systems.

中文翻译：

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纳米电化学系统中硅烷层的再现性和稳定性

有机硅烷通常用于将生物受体附着到氧化物表面。这种硅烷层的沉积在纳米级或纳米级装置（例如纳米移液器）中尤其具有挑战性，因为由于几何收缩，并且多层硅烷的厚度可能覆盖或阻挡纳米级特征，因此可能无法冲洗掉松散结合的硅烷。此外，在电化学装置中，硅烷层会经历额外的扰动，例如电迁移和电渗力。尽管其重要性，但目前的文献中似乎没有就纳米移液器硅烷化的最佳方法达成共识，所报道的条件存在显着差异。在这里，我们系统地研究了纳米移液器内液相和气相沉积的硅烷层的再现性和稳定性。对变化的内部硅烷化表面的电化学监测表明，气相沉积 APTES 产生具有最高再现性的表面改性，而气相沉积 APTMS 则在 24 小时内产生最高稳定性的表面改性。强调了硅烷化纳米限制系统的实际问题，并强调了仔细选择硅烷化条件以产生稳定且可重复的单分子层的重要性，这是新型纳米级系统开发中一个未被充分认识的方面。