| dc.description.abstract | Nanotechnology is a rapidly growing technology with applications that affect many
industries in the global economy. Two such industries are optoelectronics and
healthcare.
With the increased demand for smaller, more efficient, and more affordable device,
there is also an increased need for smaller optoelectronic components. In this work,
fabrication of metasurfaces using a solution-based nanoimprint lithography process is
investigated. The properties of silver nanoparticle ink grating and planar samples, with
and without a PMMA layers, are compared with thermally evaporated silver on a
nanoimprinted PMMA layers. The grating pattern is successfully fabricated using
nanoimprint lithography with the silver nanoparticle ink directly on a glass substrate
and on a PMMA layer. The use of PMMA was found to adversely affect the structural,
optical and electrical properties of the silver nanoparticle planar surfaces and gratings.
Gratings nanoimprinted directly into silver nanoparticle ink on a glass substrate were
found to have similar performance to gratings produced by thermal evaporation of
silver on nanoimprinted PMMA and benefit from an easier fabrication process. The
silver nanoparticle ink shows promise for the fabrication of patterned silver thin films
and may be useful for upscaling and roll-to-roll processes.
The application of nanotechnology in medicine, nanomedicine, is an area of technology
where there have been significant breakthroughs. Nanobiomaterials (NBM) are
studied extensively within nanomedicine with applications in drug delivery, contact
tracing, deep-tissue imaging, and the detection and treatment of diseases. Pre-clinical
assessment is an important step in the development of new NBMs to examine the
toxicity of the NBMs. The current state-of-the-art to assess toxicity is to use two-
dimensional (2D) cell cultures. These in vitro 2D assays lack the physiological process
present in in vivo models. However, toxicity observed in in vivo animal models is not
always observed in humans, and can make predicting possible interactions difficult.
Three-dimensional (3D) in vitro models are currently being investigated as possible
alternatives to 2D in vitro and in vivo animal models. These 3D models, or spheroids,
are more biological relevant than their 2D predecessors, with some studies using them
in pre-clinical investigations to examine dosing effects of nanoparticles.
In this work, two NBMs, LipImage™815,a liposome loaded with a near infrared dye
(IR780), and PACA(NR668), a polymeric shell loaded with far red dye (NR668), are
investigated. Using confocal microscopy, a powerful fluorescence imaging modality,
the translocation and penetration of the NBMs into the spheroid is assessed. The initial
work is carried out over a 72 h period using one concentration for each NBM.
Fluorescence intensity is observed decreasing at treatments times of up to 72 h, for
both NBMs. However, the rate at which they penetrate to the core, and become
homogenous differs for both NBMs. Fluorescence Lifetime Imaging Microscopy (FLIM)
also showed that concentration, treatment time and translocation have no affect on the
lifetime of the NBMs, suggesting the decrease in intensity observed at longer treatment
times is due to degradation of the liposome or polymeric shell, and quenching of the
encapsulated dyes. | en |
