NANOSCALE PATTERNING AND 3D ASSEMBLY FOR BIOMEDICAL APPLICATIONS

self-assembly;3D nanostructures;nano-origami;Chemical & Biomolecular Engineering

James, TeenaGracias, David H. ;

Johns Hopkins University

关键词: self-assembly;    3D nanostructures;    nano-origami;    Chemical & Biomolecular Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39292/JAMES-DISSERTATION-2014.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Due to the inherent planarity of nanoscale patterning, there is a pressing need to develop novel approaches for parallel and cost-effective three dimensional (3D) patterning and assembly at the nanoscale. The 3D devices formed by such approaches are important for chem-bio sensing, nanoelectronics and photonics, nanorobotics, and nanobiotechnology. The body of work presented in this thesis is focused on developing scalable and manufacturable processes to create curved and foldable 3D nanostructures with precise surface patterns, in a highly parallel and cost-efficient method. Specifically, two new approaches were developed which include the spontaneous curving of nanostructures using grain reflow and creation of nanopatterned channels, wells, and semiconducting conical nanopores using metal assisted plasma etching process.During plasma etching of silicon with carbon tetraflouride and oxygen, it was discovered that certain metals present during the process undergo characteristic changes. In the grain reflow process, tin grains were found to undergo grain coalescence, resulting in the spontaneous curving of structures with tight radii of curvature of the order of a few nanometers. Another approach presented in the thesis for the large scale parallel patterning in the nanoscale involves using catalytic etching of silicon, assisted by lithographically patterned noble metal geometries. Using this method, three dimensional structures such as nanopore arrays and gold (Au) nanoparticles (NPs) coated micro or nano wells and channels can be fabricated in silicon in a highly parallel fashion. I also investigated the applications of the 3D nanostructures formed by the aforementioned processes. Conical nanopore arrays were used for voltage gated biomolecular sensing and separations. Ionic transport through these pores was investigated and it was found that the rectification ratios could be enhanced by a factor of 100 by voltage gating on the semiconducting substrate alone, and that these pores could function as ionic switches with high on-off ratios. Further, multifunctional 3D nanostructures were also combined with bacteria to create a nanoscale bionic system that can be remotely controlled using a laser. Overall, these results present important advancements in the development of nanoscale patterning and 3D assembly of curved and porous nanostructures with applications in biomedical sciences and microorganism robotics.