Controlling the Morphology of Photosystem I Assembly on Thiol-Activated Au Substrates
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- 作者：Dibyendu Mukherjee ; Mark May ; Michael Vaughn ; Barry D. Bruce ; Bamin Khomami
- 刊名：Langmuir
- 出版年：2010
- 出版时间：October 19, 2010
- 年：2010
- 卷：26
- 期：20
- 页码：16048-16054
- 全文大小：1030K
- 年卷期：v.26,no.20(October 19, 2010)
- ISSN：1520-5827
文摘
Morphological variations of Photosystem I (PS I) assembly on hydroxyl-terminated alkanethiolate self-assembled monolayer (SAM)/Au substrates with various deposition techniques is presented. Our studies indicate that deposition conditions such as PS I concentration and driving force play a central role in determining organization of immobilized PS I on thiol-activated Au surfaces. Specifically, atomic force microscopy (AFM) and ellipsometry analyses indicate that gravity-driven deposition from concentrated PS I solutions results in a large number of columnar PS I aggregates, which assemble perpendicular to the Au surface. PS I deposition yields much more uniform layers when deposited at lower concentrations, suggesting preassembly of the aggregate formation in the solution phase. Moreover, in electric-field assisted deposition at high field strengths, columnar self-assembly is largely prevented, thereby allowing a uniform, monolayer-like deposition even at very high PS I concentrations. In situ dynamic light scattering (DLS) studies of solution-phase aggregation dynamics of PS I suspensions in both the presence and absence of an applied electric field support these observations and clearly demonstrate that the externally imposed electric field effectively fragments large PS I aggregates in the solution phase, thereby permitting a uniform deposition of PS I trimers on SAM/Au substrates.