Nanomedikal uygulamalar odaklı plazmonik nanoparçacık mühendisliği

Localized surface plasmon resonances grant plasmonic nanoparticles rich features that attract the attention of numerous researchers from wide ranging disciplines. Remotely triggered nanoscale heat production and strong optical contrast generation are the key attributes that render gold nanoparticles (AuNPs) widely popular especially in nanomedical applications such as photothermal cancer therapy and diagnosis. AuNPs are programmable via surface modifications to selectively target cancer cells facilitating the implementation of non-invasive cancer diagnosis and treatment at a cellular level. The variability of cancer types and the corresponding unpredictability in the structuring of the tumor tissue across individual patients represent one of the greatest challenges for the nonspecific approaches in the diagnosis and treatment of cancer. Personalized treatment strategies have been attracting special attention due to the highly irregular nature of cancer. The main motivation of this thesis is to address the increasing need for identifying the optimum AuNP morphology in the dynamic application landscape that is consistently transformed by technological developments and continuously varying demands of the changing implementation environment. The scope of this thesis covers a progressively evolving approach based on numerical simulations to establish an understanding of the interaction between the morphological features and the resulting optical properties of a plasmonic nanoparticle. Plasmonic nanoparticles of various geometries are simulated via the Lumerical and MNPBEM package for MATLAB within the 500-3000 nm spectrum spanning the entire range of biological transparency windows available. The simulations generate data pertaining to the optical properties of plasmonic nanoparticles including absorption, scattering and extinction cross-sections per individual particle; transmission, reflection and absorption for periodic array of nanoparticles; electric field in the near vicinity of the nanoparticles; and the electric current density flowing through the nanoparticle under the localized surface plasmon resonance condition. The scope of nanoparticle geometries explored in this thesis ranges from cartesian particles such as nanobars to elementary NP geometries, i.e. spherical, disk-shaped, and cylindrical nanoparticles both as monolithic, standalone structures and as self-assembling complex nanoplatforms. Engineering of large absorber silver nanobars resonant beyond 1500 nm, a wavelength range strongly dominated by scattering nanoparticles, is one of the key novelties of this thesis work. The contour design approach generates a significant change in the optical characteristics by enhancing absorption while simultaneously suppressing scattering in plasmonic nanoparticles. Another key contribution of this thesis work, building on top of the contour design approach, is the theoretical demonstration of the viability of implementing AuNP mediated cancer diagnosis and treatments in the lately discovered long wavelength transparency windows (1600-2400 nm) for the first time in literature. The design framework for engineering AuNPs constructed through a deductive analysis of an extensive dataset of fundamental AuNPs based on a data scientific perspective, represents the final key contribution of the thesis with the objective to provide guidance for future researchers working on implementations of AuNPs in a wide range of applications.