Doctor of Philosophy
Dr. François Lagugné-Labarthet
One of the major challenges in analytical and biological sciences is to develop a device to obtain unambiguous chemical and structural properties of a material or a probe biomolecule with high reproducibility and ultra-high sensitivity. Moreover, in addition to such a high sensitivity, other cases such as minimum intrusiveness, small amounts of analyte, and short acquisition time and high reproducibility are key parameters that can be valued in any analytical measurements. Among the promising methods to achieve such endeavor, plasmon-mediated surface-enhanced spectroscopic techniques, such as surface-enhanced Raman spectroscopy (SERS), are considered as suitable options. Such techniques take advantage of the interaction between an optical field and a metallic nanostructure to magnify the electromagnetic (EM) field in the proximity of the nanostructure. This results in an amplified signal of the vibrational fingerprints of the adsorbed probe molecules onto the metallic surface. Keys to obtaining ultra-sensitive SERS measurements are the development of rationally-designed plasmonic nanostructures. Besides, a major challenge for controlled and reliable sensitive measurements of probe biomolecules on biological cells gives rise due to the intrinsic random positioning and proliferation of these cells over a substrate such as a glass coverslip.
In this thesis, the rational design and development of a fluorocarbon thin film micropatterned platform is introduced for controlled programming of conventional and transfected cells proliferation over the substrate. They also provided high throughput capability of controlled neuronal network connections towards advanced imaging and sensitive detection of biomolecules of interest at nanoscale resolution. This micropatterned platform was also integrated with optimized plasmonic nanostructures fabricated by nanosphere lithography (NSL) for SERS biosensing of glycans using a Raman reporter over the positionally-controlled single cells surfaces. In addition to providing controlled plasmon-mediated measurements, the fabrications of two newly-developed 3D plasmonic nanostructures have been introduced in this thesis. These are nanopyramids arrays fabricated by NSL and arrays of nanoholes with co-registered nanocones fabricated by electron-beam lithography (EBL). These approaches have been used not only for ultra-sensitive molecular detection at the monolayer level in a variety of configurations, but also towards label-free single molecule detection at sub-femtomolar concentrations.
Tabatabaei, Mohammadali, "Design and Fabrication of Integrated Plasmonic Platforms for Ultra-sensitive Molecular and Biomolecular Detections" (2015). Electronic Thesis and Dissertation Repository. 3161.