Duleba Dominik, Denuga Shekemi, Johnson Robert P
School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
Phys Chem Chem Phys. 2024 May 29;26(21):15452-15460. doi: 10.1039/d4cp01181c.
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.
有机硅烷通常用于将生物受体连接到氧化物表面。在纳米级或纳米受限器件中，如纳米吸管中，沉积此类硅烷层尤其具有挑战性，因为由于几何限制，冲洗掉松散结合的硅烷可能是不可能的，而且多层硅烷的厚度可能会覆盖或阻挡纳米级特征。此外，在电化学器件中，硅烷层会受到额外的扰动，如电迁移和电渗力。尽管其很重要，但目前文献中对于纳米吸管硅烷化的最佳方法似乎没有达成共识，报道的条件存在很大差异。在此，我们系统地研究了纳米吸管内液相和气相沉积的硅烷层的可重复性和稳定性。对内部硅烷化表面变化的电化学监测表明，气相沉积的APTES产生的表面修饰具有最高的可重复性，而气相沉积的APTMS在24小时内产生的表面修饰具有最高的稳定性。强调了纳米受限系统硅烷化的实际问题，并强调了精心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，这在新型纳米级系统的开发中是一个未得到充分重视的方面。
