Heterogeneous Catalysis of a Copper-Coated Atomic Force Microscopy Tip for Direct-Write Click Chemistry
Heterogeneous Catalysis of a Copper-Coated Atomic Force Microscopy Tip for Direct-Write Click Chemistry
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DOI：
10.1021/ja9015974
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发表时间：
2009-05-20
影响因子：
15
通讯作者：
Stoddart, J. Fraser
中科院分区：
文献类型：
--
作者：
Paxton, Walter F.;Spruell, Jason M.;Stoddart, J. Fraser
我们报告了一种建设性扫描探针光刻方法，该方法使用异质铜涂层原子力显微镜尖端来催化溶剂化末端炔分子和硅表面叠氮封端自组装单层之间的叠氮-炔环加成反应（CuAAC）。成功地进行了空间控制的表面功能化与50 mM的乙醇溶液的小分子轴承末端炔基-炔丙胺，4-戊炔酸，和炔基-低聚环氧乙烷。我们观察到，反应只发生在与叠氮化物封端的表面接触的铜尖端，导致在50 nm的量级上的线宽的功能。通过表面形貌和侧向力显微镜测量的表面功能化程度取决于扫描力（31-350 nN）和扫描速度，即使在高达64 μ m/s的速度下也观察到显著的表面图案化。与相关的SPL技术相比，这种方法提供了一种直接写入光刻方法，以在纳米级上对表面进行结构性修改和图案化，而不需要辅助试剂。所需要的是（1）叠氮化物表面，（2）末端炔的溶液，和（3）铜涂层AFM针尖。这些优点允许在相对温和的条件下以低于100 nm的空间分辨率直接连接具有末端炔官能团的分子（包括生物分子）的潜在无限文库。
We report a constructive scanning probe lithography method that uses heterogeneous copper-coated atomic force microscopy tips to catalyze azide-alkyne cycloadditions (CuAAC) between solvated terminal alkyne molecules and azide-terminated self-assembled monolayers on silicon surfaces. Spatially controlled surface functionalization was carried out successfully with 50 mM ethanolic solutions of small molecules bearing terminal alkyne groups - propargylamine, 4-pentynoic acid, and an alkynyl-oligoethyleneoxide. We observed that reaction occurs only where the copper tip is in contact with an azide-terminated surface resulting in features with linewidths on the order of 50 nm. The extent of surface functionalization, as measured by changes in surface topography and lateral force microscopy, depends on the scanning force (31-350 nN) and scanning speed, with significant surface patterning observed even at speeds as high as 64 mu m/s. In contrast with related SPL techniques, this approach affords a direct-write lithographic approach to constructively modifying and patterning surfaces at the nanoscale without the need for auxiliary reagents. All that is required is (1) an azide surface, (2) a solution of a terminal alkyne, and (3) a copper-coated AFM tip. These advantages allow the direct attachment of a potentially limitless library of molecules that bear terminal alkyne functionalities, including biomolecules, under relatively mild conditions, with sub-100 nm spatial resolution.